2019-03-22 11:03:55 +00:00
<!DOCTYPE html>
2019-03-23 02:41:12 +00:00
< html class = "theme-next gemini use-motion" lang = "zh-Hans" >
2019-03-22 11:03:55 +00:00
< head > < meta name = "generator" content = "Hexo 3.8.0" >
< meta charset = "UTF-8" >
< meta http-equiv = "X-UA-Compatible" content = "IE=edge" >
< meta name = "viewport" content = "width=device-width, initial-scale=1, maximum-scale=1" >
< meta name = "theme-color" content = "#222" >
< meta http-equiv = "Cache-Control" content = "no-transform" >
< meta http-equiv = "Cache-Control" content = "no-siteapp" >
< link href = "/lib/fancybox/source/jquery.fancybox.css?v=2.1.5" rel = "stylesheet" type = "text/css" >
< link href = "/lib/font-awesome/css/font-awesome.min.css?v=4.6.2" rel = "stylesheet" type = "text/css" >
< link href = "/css/main.css?v=5.1.4" rel = "stylesheet" type = "text/css" >
< link rel = "apple-touch-icon" sizes = "180x180" href = "/images/apple-touch-icon-next.png?v=5.1.4" >
2019-03-23 01:29:50 +00:00
< link rel = "icon" type = "image/png" sizes = "32x32" href = "/images/hackerrank.png?v=5.1.4" >
2019-03-22 11:03:55 +00:00
2019-03-23 01:29:50 +00:00
< link rel = "icon" type = "image/png" sizes = "16x16" href = "/images/hackerrank.png?v=5.1.4" >
2019-03-22 11:03:55 +00:00
< link rel = "mask-icon" href = "/images/logo.svg?v=5.1.4" color = "#222" >
< meta name = "keywords" content = "侧信道攻击,wifi," >
< meta name = "description" content = "TCP侧信道分析及利用的学习报告背景知识测信道香农信息论 什么是信息？ 用来减少随机不确定的东西 什么是加密？ 类似于加噪声，增加随机不确定性 “从密码分析者来看，一个保密系统几乎就是一个通信系统。待传的消息是统计事件，加密所用的密钥按概率选出，加密结果为密报，这是分析者可以利用的，类似于受扰信号。” 侧信道随之出现 越过加密算法增加的随机不定性，从其他的渠道获取数据标签，确定信息内容。" >
< meta name = "keywords" content = "侧信道攻击,wifi" >
< meta property = "og:type" content = "article" >
< meta property = "og:title" content = "wifi半双工侧信道攻击学习笔记" >
< meta property = "og:url" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/index.html" >
< meta property = "og:site_name" content = "混元霹雳手" >
< meta property = "og:description" content = "TCP侧信道分析及利用的学习报告背景知识测信道香农信息论 什么是信息？ 用来减少随机不确定的东西 什么是加密？ 类似于加噪声，增加随机不确定性 “从密码分析者来看，一个保密系统几乎就是一个通信系统。待传的消息是统计事件，加密所用的密钥按概率选出，加密结果为密报，这是分析者可以利用的，类似于受扰信号。” 侧信道随之出现 越过加密算法增加的随机不定性，从其他的渠道获取数据标签，确定信息内容。" >
< meta property = "og:locale" content = "zh-Hans" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/1.png" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/2-Man_in_the_middle_attack.svg.png" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/3-Connection_TCP.png" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/5-攻击模型.PNG" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/4-netstat获取信息.jpg" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/6-GRL-R.png" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/7-GRL-L.png" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/8-收包原理.jpg" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/8-noTrigger.PNG" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/8-trigger.PNG" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/9-序列号推断.PNG" >
< meta property = "og:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/9-http注入.PNG" >
< meta property = "og:updated_time" content = "2019-03-22T10:00:16.256Z" >
< meta name = "twitter:card" content = "summary" >
< meta name = "twitter:title" content = "wifi半双工侧信道攻击学习笔记" >
< meta name = "twitter:description" content = "TCP侧信道分析及利用的学习报告背景知识测信道香农信息论 什么是信息？ 用来减少随机不确定的东西 什么是加密？ 类似于加噪声，增加随机不确定性 “从密码分析者来看，一个保密系统几乎就是一个通信系统。待传的消息是统计事件，加密所用的密钥按概率选出，加密结果为密报，这是分析者可以利用的，类似于受扰信号。” 侧信道随之出现 越过加密算法增加的随机不定性，从其他的渠道获取数据标签，确定信息内容。" >
< meta name = "twitter:image" content = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/1.png" >
< script type = "text/javascript" id = "hexo.configurations" >
var NexT = window.NexT || {};
var CONFIG = {
root: '/',
2019-03-23 02:41:12 +00:00
scheme: 'Gemini',
2019-03-22 11:03:55 +00:00
version: '5.1.4',
sidebar: {"position":"left","display":"post","offset":12,"b2t":false,"scrollpercent":false,"onmobile":false},
fancybox: true,
tabs: true,
motion: {"enable":true,"async":false,"transition":{"post_block":"fadeIn","post_header":"slideDownIn","post_body":"slideDownIn","coll_header":"slideLeftIn","sidebar":"slideUpIn"}},
duoshuo: {
userId: '0',
author: '博主'
},
algolia: {
applicationID: '',
apiKey: '',
indexName: '',
hits: {"per_page":10},
labels: {"input_placeholder":"Search for Posts","hits_empty":"We didn't find any results for the search: ${query}","hits_stats":"${hits} results found in ${time} ms"}
}
};
< / script >
< link rel = "canonical" href = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/" >
< title > wifi半双工侧信道攻击学习笔记 | 混元霹雳手< / title >
< / head >
< body itemscope itemtype = "http://schema.org/WebPage" lang = "zh-Hans" >
< div class = "container sidebar-position-left page-post-detail" >
< div class = "headband" > < / div >
< header id = "header" class = "header" itemscope itemtype = "http://schema.org/WPHeader" >
< div class = "header-inner" > < div class = "site-brand-wrapper" >
< div class = "site-meta " >
< div class = "custom-logo-site-title" >
< a href = "/" class = "brand" rel = "start" >
< span class = "logo-line-before" > < i > < / i > < / span >
< span class = "site-title" > 混元霹雳手< / span >
< span class = "logo-line-after" > < i > < / i > < / span >
< / a >
< / div >
< p class = "site-subtitle" > < / p >
< / div >
< div class = "site-nav-toggle" >
< button >
< span class = "btn-bar" > < / span >
< span class = "btn-bar" > < / span >
< span class = "btn-bar" > < / span >
< / button >
< / div >
< / div >
< nav class = "site-nav" >
< ul id = "menu" class = "menu" >
< li class = "menu-item menu-item-home" >
< a href = "/" rel = "section" >
< i class = "menu-item-icon fa fa-fw fa-home" > < / i > < br >
首页
< / a >
< / li >
< li class = "menu-item menu-item-about" >
< a href = "/about/" rel = "section" >
< i class = "menu-item-icon fa fa-fw fa-user" > < / i > < br >
关于
< / a >
< / li >
< li class = "menu-item menu-item-tags" >
< a href = "/tags/" rel = "section" >
< i class = "menu-item-icon fa fa-fw fa-tags" > < / i > < br >
标签
< / a >
< / li >
< li class = "menu-item menu-item-categories" >
< a href = "/categories/" rel = "section" >
< i class = "menu-item-icon fa fa-fw fa-th" > < / i > < br >
分类
< / a >
< / li >
< li class = "menu-item menu-item-archives" >
< a href = "/archives/" rel = "section" >
< i class = "menu-item-icon fa fa-fw fa-archive" > < / i > < br >
归档
< / a >
< / li >
2019-03-22 14:09:10 +00:00
< li class = "menu-item menu-item-search" >
< a href = "javascript:;" class = "popup-trigger" >
< i class = "menu-item-icon fa fa-search fa-fw" > < / i > < br >
搜索
< / a >
< / li >
2019-03-22 11:03:55 +00:00
< / ul >
2019-03-22 14:09:10 +00:00
< div class = "site-search" >
< div class = "popup search-popup local-search-popup" >
< div class = "local-search-header clearfix" >
< span class = "search-icon" >
< i class = "fa fa-search" > < / i >
< / span >
< span class = "popup-btn-close" >
< i class = "fa fa-times-circle" > < / i >
< / span >
< div class = "local-search-input-wrapper" >
< input autocomplete = "off" placeholder = "搜索..." spellcheck = "false" type = "text" id = "local-search-input" >
< / div >
< / div >
< div id = "local-search-result" > < / div >
< / div >
< / div >
2019-03-22 11:03:55 +00:00
< / nav >
< / div >
< / header >
< main id = "main" class = "main" >
< div class = "main-inner" >
< div class = "content-wrap" >
< div id = "content" class = "content" >
< div id = "posts" class = "posts-expand" >
< article class = "post post-type-normal" itemscope itemtype = "http://schema.org/Article" >
< div class = "post-block" >
< link itemprop = "mainEntityOfPage" href = "https://cool-y.github.io/2019/01/16/wifi半双工侧信道攻击学习笔记/" >
< span hidden itemprop = "author" itemscope itemtype = "http://schema.org/Person" >
< meta itemprop = "name" content = "Cool-Y" >
< meta itemprop = "description" content >
2019-03-22 13:49:21 +00:00
< meta itemprop = "image" content = "/images/avatar.png" >
2019-03-22 11:03:55 +00:00
< / span >
< span hidden itemprop = "publisher" itemscope itemtype = "http://schema.org/Organization" >
< meta itemprop = "name" content = "混元霹雳手" >
< / span >
< header class = "post-header" >
< h1 class = "post-title" itemprop = "name headline" > wifi半双工侧信道攻击学习笔记< / h1 >
< div class = "post-meta" >
< span class = "post-time" >
< span class = "post-meta-item-icon" >
< i class = "fa fa-calendar-o" > < / i >
< / span >
< span class = "post-meta-item-text" > 发表于< / span >
< time title = "创建于" itemprop = "dateCreated datePublished" datetime = "2019-01-16T15:35:27+08:00" >
2019-01-16
< / time >
< / span >
< span class = "post-category" >
< span class = "post-meta-divider" > |< / span >
< span class = "post-meta-item-icon" >
< i class = "fa fa-folder-o" > < / i >
< / span >
< span class = "post-meta-item-text" > 分类于< / span >
< span itemprop = "about" itemscope itemtype = "http://schema.org/Thing" >
< a href = "/categories/顶会论文/" itemprop = "url" rel = "index" >
< span itemprop = "name" > 顶会论文< / span >
< / a >
< / span >
< / span >
< span class = "post-comments-count" >
< span class = "post-meta-divider" > |< / span >
< span class = "post-meta-item-icon" >
< i class = "fa fa-comment-o" > < / i >
< / span >
< a href = "/2019/01/16/wifi半双工侧信道攻击学习笔记/#comments" itemprop = "discussionUrl" >
< span class = "post-comments-count gitment-comments-count" data-xid = "/2019/01/16/wifi半双工侧信道攻击学习笔记/" itemprop = "commentsCount" > < / span >
< / a >
< / span >
< span id = "/2019/01/16/wifi半双工侧信道攻击学习笔记/" class = "leancloud_visitors" data-flag-title = "wifi半双工侧信道攻击学习笔记" >
< span class = "post-meta-divider" > |< / span >
< span class = "post-meta-item-icon" >
< i class = "fa fa-eye" > < / i >
< / span >
< span class = "post-meta-item-text" > 阅读次数: < / span >
< span class = "leancloud-visitors-count" > < / span >
< / span >
< / div >
< / header >
< div class = "post-body" itemprop = "articleBody" >
< h1 id = "TCP侧信道分析及利用的学习报告" > < a href = "#TCP侧信道分析及利用的学习报告" class = "headerlink" title = "TCP侧信道分析及利用的学习报告" > < / a > TCP侧信道分析及利用的学习报告< / h1 > < h2 id = "背景知识" > < a href = "#背景知识" class = "headerlink" title = "背景知识" > < / a > 背景知识< / h2 > < h3 id = "测信道" > < a href = "#测信道" class = "headerlink" title = "测信道" > < / a > 测信道< / h3 > < p > < strong > 香农信息论< / strong > < / p >
< p > < img src = "./1.png" alt = "信息熵" > < / p >
< p > < strong > 什么是信息？< / strong > 用来减少随机不确定的东西< / p >
< p > < strong > 什么是加密？< / strong > 类似于加噪声，增加随机不确定性< / p >
< blockquote >
< p > “从密码分析者来看，一个保密系统几乎就是一个通信系统。待传的消息是统计事件，加密所用的密钥按概率选出，加密结果为密报，这是分析者可以利用的，类似于受扰信号。”< / p >
< / blockquote >
< p > < strong > 侧信道随之出现< / strong > 越过加密算法增加的随机不定性，从其他的渠道获取数据标签，确定信息内容。< / p >
< ol >
< li > 早期：采集加密电子设备在运行过程中的时间消耗、功率消耗或者电磁辐射消耗等边缘信息的差异性< / li >
< li > 而随着研究的深入， < / li >
< li > 并在Web应用交互信息传递越来越频繁时， < / li >
< / ol >
< p > < strong > 侧信道攻击的流程< / strong > 第一个就是侧信道泄露的截取，第二个是信息的恢复。< / p >
< hr >
< h3 id = "网络攻击" > < a href = "#网络攻击" class = "headerlink" title = "网络攻击" > < / a > 网络攻击< / h3 > < ol >
< li > 中间人攻击< blockquote >
< p > “指攻击者与通讯的两端分别创建独立的联系，并交换其所收到的数据，使通讯的两端认为他们正在通过一个私密的连接与对方直接对话，但事实上整个会话都被攻击者完全控制。”< / p >
< / blockquote >
< / li >
< / ol >
< p > < img src = "./2-Man_in_the_middle_attack.svg.png" alt > < / p >
< ul >
< li > 公共wifi、路由器劫持< / li >
< li > 一般使用加密来防御< / li >
< li > 加密的代价：维护密钥证书、影响功能（运营商无法做缓存）< / li >
< / ul >
< ol start = "2" >
< li > 非中间人攻击/偏离路径攻击/off-path attack< blockquote >
< p > 通信线路之外，攻击者看不到双方的消息，没办法截获和发送通信包。智能伪造成一方给另一方发消息。< / p >
< / blockquote >
< / li >
< / ol >
< ul >
< li > 攻击成功需要：消息合法+最先到达< / li >
< li > 防御措施： < br > 双方在通信前交换一个随机数，这个随机数在每次的通信中都要被附带，而中间人看不见这个随机数，因此伪造的消息被认为不合法。< / li >
< li > 攻击者如何得到这个随机数：侧信道< / li >
< / ul >
< hr >
< h3 id = "TCP三次握手" > < a href = "#TCP三次握手" class = "headerlink" title = "TCP三次握手" > < / a > TCP三次握手< / h3 > < p > < img src = "./3-Connection_TCP.png" alt > < / p >
< blockquote >
< ol >
< li > 客户端通过向服务器端发送一个SYN来创建一个主动打开， < em > 随机数A< / em > 。< / li >
< li > 服务器端应当为一个合法的SYN回送一个SYN/ACK。ACK的确认码应为A+1， < em > 随机产生的序号B< / em > 。< / li >
< li > 最后， ， ， ， < / li >
< / ol >
< / blockquote >
< p > 通过三次握手，确定对方不是非中间人< / p >
< p > < strong > < em > TCP序列号的问题< / em > < / strong > < / p >
< table >
< thead >
< tr >
< th style = "text-align:center" > 1985< / th >
< th style = "text-align:center" > 1995< / th >
< th style = "text-align:center" > 2001< / th >
< th style = "text-align:center" > 2004< / th >
< th style = "text-align:center" > 2007< / th >
< th style = "text-align:center" > 2012< / th >
< th style = "text-align:center" > 2012< / th >
< th style = "text-align:center" > 2016< / th >
< / tr >
< / thead >
< tbody >
< tr >
< td style = "text-align:center" > Morris< / td >
< td style = "text-align:center" > Mitnik< / td >
< td style = "text-align:center" > Zalewsky< / td >
< td style = "text-align:center" > Waston< / td >
< td style = "text-align:center" > kLM< / td >
< td style = "text-align:center" > Herzberg< / td >
< td style = "text-align:center" > 作者< / td >
< td style = "text-align:center" > 作者< / td >
< / tr >
< tr >
< td style = "text-align:center" > 初始序列可预测< / td >
< td style = "text-align:center" > 真实利用< / td >
< td style = "text-align:center" > 漏洞仍在< / td >
< td style = "text-align:center" > BGP DoS< / td >
< td style = "text-align:center" > Windows攻击< / td >
< td style = "text-align:center" > Puppet-assisted< / td >
< td style = "text-align:center" > Malware-assisted< / td >
< td style = "text-align:center" > off-path attack< / td >
< / tr >
< / tbody >
< / table >
< ol >
< li > 90年代时发现并不随机： < / li >
< li > 2007年在windows场景下用IDID侧信道猜出序列号： ， < / li >
< / ol >
< hr >
< h2 id = "Malware-assisted" > < a href = "#Malware-assisted" class = "headerlink" title = "Malware-assisted" > < / a > Malware-assisted< / h2 > < p > < strong > 攻击模型：< / strong > < br > 给受害者安装一个无特权的应用程序（ ） ， ， < br > < img src = "./5-攻击模型.PNG" alt > < / p >
< p > < strong > 如何劫持TCP< / strong > < / p >
< ol >
< li > < p > 需要的信息： ， ， < br > 使用netstat命令获取： < br > < img src = "./4-netstat获取信息.jpg" alt > < / p >
< / li >
< li > < p > 任务： ， < / p >
< / li >
< li > 如何验证序列号正确：通过某种侧信道，这个恶意软件在后台可以提供反馈。< / li >
< / ol >
< h3 id = "变种一：防火墙" > < a href = "#变种一：防火墙" class = "headerlink" title = "变种一：防火墙" > < / a > 变种一：防火墙< / h3 > < p > < strong > 攻击过程：< / strong > TCP三次握手之后产生A和B， ， ， ， ， < / p >
< p > < strong > 具体侧信道方案：< / strong > CPU资源使用率（ ） > TCP计数器（ ） > 低噪音计数器：包被丢掉时，一个相应的错误计数器。< / p >
< p > < strong > 解决方法：< / strong > 关闭防火墙检查序列号的功能< / p >
< h3 id = "变种二：无防火墙" > < a href = "#变种二：无防火墙" class = "headerlink" title = "变种二：无防火墙" > < / a > 变种二：无防火墙< / h3 > < p > 具体侧信道方案： ， < br > 影响范围： < / p >
< hr >
< h2 id = "Pure-off-path-无恶意软件协助" > < a href = "#Pure-off-path-无恶意软件协助" class = "headerlink" title = "Pure off-path:无恶意软件协助" > < / a > Pure off-path:无恶意软件协助< / h2 > < blockquote >
< p > 不植入恶意软件， ： ， < / p >
< / blockquote >
< h3 id = "Global-Rate-Limit" > < a href = "#Global-Rate-Limit" class = "headerlink" title = "Global Rate Limit" > < / a > Global Rate Limit< / h3 > < blockquote >
< p > USENIX 2016 : Off-Path TCP Exploits: Global Rate Limit Considered Dangerous< / p >
< / blockquote >
< p > < strong > 侧信道：< / strong > 所有的侧信道， ， < strong > < em > 服务器上< / em > < / strong > 的共享资源，< strong > < em > 限速器< / em > < / strong > （ ） （ ） < / p >
< p > < strong > 如何利用共享限速器：< / strong > < br > 先判断是否建立了连接。然后伪造TCP包， ， ， ， ， （ ） ； ， < / p >
< p > < img src = "./6-GRL-R.png" alt > < / p >
< p > < img src = "./7-GRL-L.png" alt > < / p >
< p > < strong > 评估：< / strong > 是否建立了连接：< 10s ; Seq： ； < 10s< / p >
< p > < strong > 解决方案：< / strong > 1. 加噪音， ； < / p >
< hr >
< h3 id = "Unfixable-WiFi-timing" > < a href = "#Unfixable-WiFi-timing" class = "headerlink" title = "Unfixable WiFi timing" > < / a > Unfixable WiFi timing< / h3 > < blockquote >
< p > USENIX 2018 : Off-Path TCP Exploit: How Wireless Routers< br > Can Jeopardize Your Secrets< br > 之前的漏洞无论是计数器还是限速器都属于软件，很好更正，但这篇文章的漏洞利用无法修复。< / p >
< / blockquote >
< p > < strong > TCP收包的原理： < / strong > 通常TCP收包要看这个包是否匹配了当前的某一个连接。如果连接匹配上了， ； ， ， ； ， ， ， < br > < img src = "./8-收包原理.jpg" alt > < / p >
< p > < strong > 侧信道：< / strong > 攻击者伪装成服务器给客户端发包，正确的序列号会有< strong > < em > 回复< / em > < / strong > ，错误则没有。但回复时发送给服务器的，有没有回复攻击者并不知道。那么如何去判断有没有回复，利用无线网络的 < strong > < em > 半双工< / em > < / strong > 传输。< br > 让有回包和没有回包的时间差异放大。< / p >
< p > < strong > 判断流程：< / strong > 客户端和路由器之间wifi通信。攻击者依次发送三个数据包， ， ， ， ， < br > < img src = "./8-noTrigger.PNG" alt > < / p >
< p > < img src = "./8-trigger.PNG" alt > < / p >
< p > < strong > 评估：< / strong > 在本地环境下， ， < / p >
< p > < strong > 攻击应用：< / strong > < br > < strong > 1. 攻击模型：< / strong > 受害者访问了我们的钓鱼网站， （ ） ， （ ） ， < / p >
< blockquote >
< p > 与理想情况的不同： ； < / p >
< / blockquote >
< pre > < code > Attacker -------wire----------|
Router ---------wireless-------Victim (client)
Server -------wire----------|
< / code > < / pre > < p > < strong > 2. 攻击目标：< / strong > 推断出客户端和服务器是否建立了连接； ； （ ） ， ， ， < / p >
< p > < strong > 3. 攻击过程：< / strong > 假设傀儡已经建立了连接， （ ） ， ， ， ， ， ， ， < / p >
< p > < strong > 4. 细节：< / strong > < / p >
< ul >
< li > < strong > 连接（四元组）推断：< / strong > 每一轮使用30个重复包测试一个端口， ， < strong > < em > web缓存投毒< / em > < / strong > ，还需要傀儡初始化连接来协助，根据系统不同，有不同的端口选择算法可以优化：< strong > < em > windows& macOS< / em > < / strong > 使用全局和顺序端口分配策略为其TCP连接选择短暂的端口号， ， < strong > < em > NAT< / em > < / strong > 端口保留，不需要关心外部端口被转换成不可预知的内部端口。< strong > < em > 来自同一域名的多个IP地址< / em > < / strong > ，这意味着攻击者需要付出更大的代价来推断端口号。< / li >
< li > < strong > 序列号推断：< / strong > 通过利用时序侧信道来判断是否存在相应的响应，从而将窗口序列号与窗外序列号区分开来。一旦我们得到一个 < strong > < em > 窗口内序列号< / em > < / strong > ，通过进行二分搜索进一步将序列号空间缩小到单个值 < strong > < em > RCV.NXT< / em > < / strong > 。如果还要使用傀儡建立的连接发起web缓存投毒， ： < strong > < em > 增大接收窗口的大小< / em > < / strong > ， ， ， < br > < img src = "./9-序列号推断.PNG" alt > < / li >
< li > < p > < strong > TCP劫持： < / strong > 通过劫持傀儡初始化的连接， ， < strong > < em > windows< / em > < / strong > ： ， < br > 因此， ， < strong > < em > （ ） < / em > < / strong > ， ， ， ， ， ， < / p >
< 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" > websocket.send(|wnd|*i)< / span > < br > < / pre > < / td > < / tr > < / table > < / figure >
< p > 因此， ， ， ， < br > < img src = "./9-http注入.PNG" alt > < br > < strong > < em > （ ） < / em > < / strong > ， ， ， （ ） ， < br > 此外， ， ， （ ） ， ， ， ， < / p >
< / li >
< / ul >
< hr >
< h2 id = "Discussion" > < a href = "#Discussion" class = "headerlink" title = "Discussion" > < / a > Discussion< / h2 > < p > 时序侧信道来自无线网络的半双工性质。由于无线协议中固有的冲突和回退， ， ， < br > 虽然作者只讨论威胁模型， ， （ ， ） ， （ ） < br > 此外， ， ， ， ， ， ， < / p >
< / div >
2019-03-22 12:33:24 +00:00
< div >
< div style = "padding: 10px 0; margin: 20px auto; width: 90%; text-align: center;" >
< div > 您的支持将鼓励我继续创作！< / div >
< button id = "rewardButton" disable = "enable" onclick = "var qr = document.getElementById('QR'); if (qr.style.display === 'none') {qr.style.display='block';} else {qr.style.display='none'}" >
< span > 打赏< / span >
< / button >
< div id = "QR" style = "display: none;" >
< div id = "wechat" style = "display: inline-block" >
2019-03-22 13:20:22 +00:00
< img id = "wechat_qr" src = "/images/Wechatpay.png" alt = "Cool-Y 微信支付" >
2019-03-22 12:33:24 +00:00
< p > 微信支付< / p >
< / div >
< div id = "alipay" style = "display: inline-block" >
2019-03-22 13:25:11 +00:00
< img id = "alipay_qr" src = "/images/Alipay.png" alt = "Cool-Y 支付宝" >
2019-03-22 12:33:24 +00:00
< p > 支付宝< / p >
< / div >
< / div >
< / div >
< / div >
2019-03-22 11:03:55 +00:00
< footer class = "post-footer" >
< div class = "post-tags" >
< a href = "/tags/侧信道攻击/" rel = "tag" > # 侧信道攻击< / a >
< a href = "/tags/wifi/" rel = "tag" > # wifi< / a >
< / div >
< div class = "post-nav" >
< div class = "post-nav-next post-nav-item" >
< a href = "/2018/11/16/BIBA访问控制模型实现(python)/" rel = "next" title = "利用python实现BIBA模型" >
< i class = "fa fa-chevron-left" > < / i > 利用python实现BIBA模型
< / a >
< / div >
< span class = "post-nav-divider" > < / span >
< div class = "post-nav-prev post-nav-item" >
< a href = "/2019/02/22/qq数据库的加密解密/" rel = "prev" title = "QQ数据库的加密与解密" >
QQ数据库的加密与解密 < i class = "fa fa-chevron-right" > < / i >
< / a >
< / div >
< / div >
< / footer >
< / div >
< / article >
< div class = "post-spread" >
< / div >
< / div >
< / div >
< div class = "comments" id = "comments" >
< div id = "gitment-container" > < / div >
< / div >
< / div >
< div class = "sidebar-toggle" >
< div class = "sidebar-toggle-line-wrap" >
< span class = "sidebar-toggle-line sidebar-toggle-line-first" > < / span >
< span class = "sidebar-toggle-line sidebar-toggle-line-middle" > < / span >
< span class = "sidebar-toggle-line sidebar-toggle-line-last" > < / span >
< / div >
< / div >
< aside id = "sidebar" class = "sidebar" >
< div class = "sidebar-inner" >
< ul class = "sidebar-nav motion-element" >
< li class = "sidebar-nav-toc sidebar-nav-active" data-target = "post-toc-wrap" >
文章目录
< / li >
< li class = "sidebar-nav-overview" data-target = "site-overview-wrap" >
站点概览
< / li >
< / ul >
< section class = "site-overview-wrap sidebar-panel" >
< div class = "site-overview" >
< div class = "site-author motion-element" itemprop = "author" itemscope itemtype = "http://schema.org/Person" >
2019-03-22 13:49:21 +00:00
< img class = "site-author-image" itemprop = "image" src = "/images/avatar.png" alt = "Cool-Y" >
2019-03-22 11:03:55 +00:00
< p class = "site-author-name" itemprop = "name" > Cool-Y< / p >
< p class = "site-description motion-element" itemprop = "description" > < / p >
< / div >
< nav class = "site-state motion-element" >
< div class = "site-state-item site-state-posts" >
< a href = "/archives/" >
< span class = "site-state-item-count" > 5< / span >
< span class = "site-state-item-name" > 日志< / span >
< / a >
< / div >
< div class = "site-state-item site-state-categories" >
< a href = "/categories/index.html" >
< span class = "site-state-item-count" > 4< / span >
< span class = "site-state-item-name" > 分类< / span >
< / a >
< / div >
< div class = "site-state-item site-state-tags" >
< a href = "/tags/index.html" >
< span class = "site-state-item-count" > 11< / span >
< span class = "site-state-item-name" > 标签< / span >
< / a >
< / div >
< / nav >
2019-03-22 13:39:30 +00:00
< div class = "links-of-author motion-element" >
< span class = "links-of-author-item" >
2019-03-22 13:40:50 +00:00
< a href = "https://github.com/Cool-Y" target = "_blank" title = "GitHub" >
2019-03-22 13:39:30 +00:00
< i class = "fa fa-fw fa-github" > < / i > GitHub< / a >
< / span >
< span class = "links-of-author-item" >
< a href = "http://weibo.com/HanYanOpenFire" target = "_blank" title = "Weibo" >
< i class = "fa fa-fw fa-weibo" > < / i > Weibo< / a >
< / span >
< span class = "links-of-author-item" >
< a href = "mailto:cool.yim@whu.edu.cn" target = "_blank" title = "E-Mail" >
< i class = "fa fa-fw fa-envelope" > < / i > E-Mail< / a >
< / span >
< span class = "links-of-author-item" >
< a href = "https://www.instagram.com/yan__han/" target = "_blank" title = "Instagram" >
< i class = "fa fa-fw fa-instagram" > < / i > Instagram< / a >
< / span >
< / div >
2019-03-22 11:03:55 +00:00
< / div >
< / section >
<!-- noindex -->
< section class = "post-toc-wrap motion-element sidebar-panel sidebar-panel-active" >
< div class = "post-toc" >
< div class = "post-toc-content" > < ol class = "nav" > < li class = "nav-item nav-level-1" > < a class = "nav-link" href = "#TCP侧信道分析及利用的学习报告" > < span class = "nav-number" > 1.< / span > < span class = "nav-text" > TCP侧信道分析及利用的学习报告< / span > < / a > < ol class = "nav-child" > < li class = "nav-item nav-level-2" > < a class = "nav-link" href = "#背景知识" > < span class = "nav-number" > 1.1.< / span > < span class = "nav-text" > 背景知识< / span > < / a > < ol class = "nav-child" > < li class = "nav-item nav-level-3" > < a class = "nav-link" href = "#测信道" > < span class = "nav-number" > 1.1.1.< / span > < span class = "nav-text" > 测信道< / span > < / a > < / li > < li class = "nav-item nav-level-3" > < a class = "nav-link" href = "#网络攻击" > < span class = "nav-number" > 1.1.2.< / span > < span class = "nav-text" > 网络攻击< / span > < / a > < / li > < li class = "nav-item nav-level-3" > < a class = "nav-link" href = "#TCP三次握手" > < span class = "nav-number" > 1.1.3.< / span > < span class = "nav-text" > TCP三次握手< / span > < / a > < / li > < / ol > < / li > < li class = "nav-item nav-level-2" > < a class = "nav-link" href = "#Malware-assisted" > < span class = "nav-number" > 1.2.< / span > < span class = "nav-text" > Malware-assisted< / span > < / a > < ol class = "nav-child" > < li class = "nav-item nav-level-3" > < a class = "nav-link" href = "#变种一：防火墙" > < span class = "nav-number" > 1.2.1.< / span > < span class = "nav-text" > 变种一：防火墙< / span > < / a > < / li > < li class = "nav-item nav-level-3" > < a class = "nav-link" href = "#变种二：无防火墙" > < span class = "nav-number" > 1.2.2.< / span > < span class = "nav-text" > 变种二：无防火墙< / span > < / a > < / li > < / ol > < / li > < li class = "nav-item nav-level-2" > < a class = "nav-link" href = "#Pure-off-path-无恶意软件协助" > < span class = "nav-number" > 1.3.< / span > < span class = "nav-text" > Pure off-path:无恶意软件协助< / span > < / a > < ol class = "nav-child" > < li class = "nav-item nav-level-3" > < a class = "nav-link" href = "#Global-Rate-Limit" > < span class = "nav-number" > 1.3.1.< / span > < span class = "nav-text" > Global Rate Limit< / span > < / a > < / li > < li class = "nav-item nav-level-3" > < a class = "nav-link" href = "#Unfixable-WiFi-timing" > < span class = "nav-number" > 1.3.2.< / span > < span class = "nav-text" > Unfixable WiFi timing< / span > < / a > < / li > < / ol > < / li > < li class = "nav-item nav-level-2" > < a class = "nav-link" href = "#Discussion" > < span class = "nav-number" > 1.4.< / span > < span class = "nav-text" > Discussion< / span > < / a > < / li > < / ol > < / li > < / ol > < / div >
< / div >
< / section >
<!-- /noindex -->
< / div >
< / aside >
< / div >
< / main >
< footer id = "footer" class = "footer" >
< div class = "footer-inner" >
< div class = "copyright" > © < span itemprop = "copyrightYear" > 2019< / span >
< span class = "with-love" >
< i class = "fa fa-user" > < / i >
< / span >
< span class = "author" itemprop = "copyrightHolder" > Cool-Y< / span >
< / div >
< div class = "powered-by" > 由 < a class = "theme-link" target = "_blank" href = "https://hexo.io" > Hexo< / a > 强力驱动< / div >
< span class = "post-meta-divider" > |< / span >
2019-03-23 02:41:12 +00:00
< div class = "theme-info" > 主题 — < a class = "theme-link" target = "_blank" href = "https://github.com/iissnan/hexo-theme-next" > NexT.Gemini< / a > v5.1.4< / div >
2019-03-22 11:03:55 +00:00
< / div >
< / footer >
< div class = "back-to-top" >
< i class = "fa fa-arrow-up" > < / i >
< / div >
< / div >
< script type = "text/javascript" >
if (Object.prototype.toString.call(window.Promise) !== '[object Function]') {
window.Promise = null;
}
< / script >
< script type = "text/javascript" src = "/lib/jquery/index.js?v=2.1.3" > < / script >
< script type = "text/javascript" src = "/lib/fastclick/lib/fastclick.min.js?v=1.0.6" > < / script >
< script type = "text/javascript" src = "/lib/jquery_lazyload/jquery.lazyload.js?v=1.9.7" > < / script >
< script type = "text/javascript" src = "/lib/velocity/velocity.min.js?v=1.2.1" > < / script >
< script type = "text/javascript" src = "/lib/velocity/velocity.ui.min.js?v=1.2.1" > < / script >
< script type = "text/javascript" src = "/lib/fancybox/source/jquery.fancybox.pack.js?v=2.1.5" > < / script >
< script type = "text/javascript" src = "/js/src/utils.js?v=5.1.4" > < / script >
< script type = "text/javascript" src = "/js/src/motion.js?v=5.1.4" > < / script >
2019-03-23 01:54:13 +00:00
< script type = "text/javascript" src = "/js/src/affix.js?v=5.1.4" > < / script >
< script type = "text/javascript" src = "/js/src/schemes/pisces.js?v=5.1.4" > < / script >
2019-03-22 11:03:55 +00:00
< script type = "text/javascript" src = "/js/src/scrollspy.js?v=5.1.4" > < / script >
< script type = "text/javascript" src = "/js/src/post-details.js?v=5.1.4" > < / script >
< script type = "text/javascript" src = "/js/src/bootstrap.js?v=5.1.4" > < / script >
<!-- LOCAL: You can save these files to your site and update links -->
< link rel = "stylesheet" href = "https://aimingoo.github.io/gitmint/style/default.css" >
< script src = "https://aimingoo.github.io/gitmint/dist/gitmint.browser.js" > < / script >
<!-- END LOCAL -->
< script type = "text/javascript" >
function renderGitment(){
var gitment = new Gitmint({
id: window.location.pathname,
owner: 'Cool-Y',
repo: 'gitment-comments',
lang: "" || navigator.language || navigator.systemLanguage || navigator.userLanguage,
oauth: {
client_secret: '1c5db4da72df5e6fc318d12afe5f4406f7c54343',
client_id: '180955a2c3ae3d966d9a'
}});
gitment.render('gitment-container');
}
renderGitment();
< / script >
2019-03-22 14:09:10 +00:00
< script type = "text/javascript" >
// Popup Window;
var isfetched = false;
var isXml = true;
// Search DB path;
var search_path = "search.xml";
if (search_path.length === 0) {
search_path = "search.xml";
} else if (/json$/i.test(search_path)) {
isXml = false;
}
var path = "/" + search_path;
// monitor main search box;
var onPopupClose = function (e) {
$('.popup').hide();
$('#local-search-input').val('');
$('.search-result-list').remove();
$('#no-result').remove();
$(".local-search-pop-overlay").remove();
$('body').css('overflow', '');
}
function proceedsearch() {
$("body")
.append('< div class = "search-popup-overlay local-search-pop-overlay" > < / div > ')
.css('overflow', 'hidden');
$('.search-popup-overlay').click(onPopupClose);
$('.popup').toggle();
var $localSearchInput = $('#local-search-input');
$localSearchInput.attr("autocapitalize", "none");
$localSearchInput.attr("autocorrect", "off");
$localSearchInput.focus();
}
// search function;
var searchFunc = function(path, search_id, content_id) {
'use strict';
// start loading animation
$("body")
.append('< div class = "search-popup-overlay local-search-pop-overlay" > ' +
'< div id = "search-loading-icon" > ' +
'< i class = "fa fa-spinner fa-pulse fa-5x fa-fw" > < / i > ' +
'< / div > ' +
'< / div > ')
.css('overflow', 'hidden');
$("#search-loading-icon").css('margin', '20% auto 0 auto').css('text-align', 'center');
$.ajax({
url: path,
dataType: isXml ? "xml" : "json",
async: true,
success: function(res) {
// get the contents from search data
isfetched = true;
$('.popup').detach().appendTo('.header-inner');
var datas = isXml ? $("entry", res).map(function() {
return {
title: $("title", this).text(),
content: $("content",this).text(),
url: $("url" , this).text()
};
}).get() : res;
var input = document.getElementById(search_id);
var resultContent = document.getElementById(content_id);
var inputEventFunction = function() {
var searchText = input.value.trim().toLowerCase();
var keywords = searchText.split(/[\s\-]+/);
if (keywords.length > 1) {
keywords.push(searchText);
}
var resultItems = [];
if (searchText.length > 0) {
// perform local searching
datas.forEach(function(data) {
var isMatch = false;
var hitCount = 0;
var searchTextCount = 0;
var title = data.title.trim();
var titleInLowerCase = title.toLowerCase();
var content = data.content.trim().replace(/< [^>]+>/g,"");
var contentInLowerCase = content.toLowerCase();
var articleUrl = decodeURIComponent(data.url);
var indexOfTitle = [];
var indexOfContent = [];
// only match articles with not empty titles
if(title != '') {
keywords.forEach(function(keyword) {
function getIndexByWord(word, text, caseSensitive) {
var wordLen = word.length;
if (wordLen === 0) {
return [];
}
var startPosition = 0, position = [], index = [];
if (!caseSensitive) {
text = text.toLowerCase();
word = word.toLowerCase();
}
while ((position = text.indexOf(word, startPosition)) > -1) {
index.push({position: position, word: word});
startPosition = position + wordLen;
}
return index;
}
indexOfTitle = indexOfTitle.concat(getIndexByWord(keyword, titleInLowerCase, false));
indexOfContent = indexOfContent.concat(getIndexByWord(keyword, contentInLowerCase, false));
});
if (indexOfTitle.length > 0 || indexOfContent.length > 0) {
isMatch = true;
hitCount = indexOfTitle.length + indexOfContent.length;
}
}
// show search results
if (isMatch) {
// sort index by position of keyword
[indexOfTitle, indexOfContent].forEach(function (index) {
index.sort(function (itemLeft, itemRight) {
if (itemRight.position !== itemLeft.position) {
return itemRight.position - itemLeft.position;
} else {
return itemLeft.word.length - itemRight.word.length;
}
});
});
// merge hits into slices
function mergeIntoSlice(text, start, end, index) {
var item = index[index.length - 1];
var position = item.position;
var word = item.word;
var hits = [];
var searchTextCountInSlice = 0;
while (position + word.length < = end & & index.length != 0) {
if (word === searchText) {
searchTextCountInSlice++;
}
hits.push({position: position, length: word.length});
var wordEnd = position + word.length;
// move to next position of hit
index.pop();
while (index.length != 0) {
item = index[index.length - 1];
position = item.position;
word = item.word;
if (wordEnd > position) {
index.pop();
} else {
break;
}
}
}
searchTextCount += searchTextCountInSlice;
return {
hits: hits,
start: start,
end: end,
searchTextCount: searchTextCountInSlice
};
}
var slicesOfTitle = [];
if (indexOfTitle.length != 0) {
slicesOfTitle.push(mergeIntoSlice(title, 0, title.length, indexOfTitle));
}
var slicesOfContent = [];
while (indexOfContent.length != 0) {
var item = indexOfContent[indexOfContent.length - 1];
var position = item.position;
var word = item.word;
// cut out 100 characters
var start = position - 20;
var end = position + 80;
if(start < 0 ) {
start = 0;
}
if (end < position + word . length ) {
end = position + word.length;
}
if(end > content.length){
end = content.length;
}
slicesOfContent.push(mergeIntoSlice(content, start, end, indexOfContent));
}
// sort slices in content by search text's count and hits' count
slicesOfContent.sort(function (sliceLeft, sliceRight) {
if (sliceLeft.searchTextCount !== sliceRight.searchTextCount) {
return sliceRight.searchTextCount - sliceLeft.searchTextCount;
} else if (sliceLeft.hits.length !== sliceRight.hits.length) {
return sliceRight.hits.length - sliceLeft.hits.length;
} else {
return sliceLeft.start - sliceRight.start;
}
});
// select top N slices in content
var upperBound = parseInt('1');
if (upperBound >= 0) {
slicesOfContent = slicesOfContent.slice(0, upperBound);
}
// highlight title and content
function highlightKeyword(text, slice) {
var result = '';
var prevEnd = slice.start;
slice.hits.forEach(function (hit) {
result += text.substring(prevEnd, hit.position);
var end = hit.position + hit.length;
result += '< b class = "search-keyword" > ' + text.substring(hit.position, end) + '< / b > ';
prevEnd = end;
});
result += text.substring(prevEnd, slice.end);
return result;
}
var resultItem = '';
if (slicesOfTitle.length != 0) {
resultItem += "< li > < a href = '" + articleUrl + "' class = 'search-result-title' > " + highlightKeyword(title, slicesOfTitle[0]) + "< / a > ";
} else {
resultItem += "< li > < a href = '" + articleUrl + "' class = 'search-result-title' > " + title + "< / a > ";
}
slicesOfContent.forEach(function (slice) {
resultItem += "< a href = '" + articleUrl + "' > " +
"< p class = \"search-result\" > " + highlightKeyword(content, slice) +
"...< / p > " + "< / a > ";
});
resultItem += "< / li > ";
resultItems.push({
item: resultItem,
searchTextCount: searchTextCount,
hitCount: hitCount,
id: resultItems.length
});
}
})
};
if (keywords.length === 1 & & keywords[0] === "") {
resultContent.innerHTML = '< div id = "no-result" > < i class = "fa fa-search fa-5x" / > < / div > '
} else if (resultItems.length === 0) {
resultContent.innerHTML = '< div id = "no-result" > < i class = "fa fa-frown-o fa-5x" / > < / div > '
} else {
resultItems.sort(function (resultLeft, resultRight) {
if (resultLeft.searchTextCount !== resultRight.searchTextCount) {
return resultRight.searchTextCount - resultLeft.searchTextCount;
} else if (resultLeft.hitCount !== resultRight.hitCount) {
return resultRight.hitCount - resultLeft.hitCount;
} else {
return resultRight.id - resultLeft.id;
}
});
var searchResultList = '< ul class = \"search-result-list\" > ';
resultItems.forEach(function (result) {
searchResultList += result.item;
})
searchResultList += "< / ul > ";
resultContent.innerHTML = searchResultList;
}
}
if ('auto' === 'auto') {
input.addEventListener('input', inputEventFunction);
} else {
$('.search-icon').click(inputEventFunction);
input.addEventListener('keypress', function (event) {
if (event.keyCode === 13) {
inputEventFunction();
}
});
}
// remove loading animation
$(".local-search-pop-overlay").remove();
$('body').css('overflow', '');
proceedsearch();
}
});
}
// handle and trigger popup window;
$('.popup-trigger').click(function(e) {
e.stopPropagation();
if (isfetched === false) {
searchFunc(path, 'local-search-input', 'local-search-result');
} else {
proceedsearch();
};
});
$('.popup-btn-close').click(onPopupClose);
$('.popup').click(function(e){
e.stopPropagation();
});
$(document).on('keyup', function (event) {
var shouldDismissSearchPopup = event.which === 27 & &
$('.search-popup').is(':visible');
if (shouldDismissSearchPopup) {
onPopupClose();
}
});
< / script >
2019-03-22 11:03:55 +00:00
< script src = "https://cdn1.lncld.net/static/js/av-core-mini-0.6.4.js" > < / script >
< script > AV . initialize ( "EWwoJgHNdlj6iBjiFlMcabUO-gzGzoHsz" , "x8FxDrYG79C8YFrTww9ljo8K" ) ; < / script >
< script >
function showTime(Counter) {
var query = new AV.Query(Counter);
var entries = [];
var $visitors = $(".leancloud_visitors");
$visitors.each(function () {
entries.push( $(this).attr("id").trim() );
});
query.containedIn('url', entries);
query.find()
.done(function (results) {
var COUNT_CONTAINER_REF = '.leancloud-visitors-count';
if (results.length === 0) {
$visitors.find(COUNT_CONTAINER_REF).text(0);
return;
}
for (var i = 0; i < results.length ; i + + ) {
var item = results[i];
var url = item.get('url');
var time = item.get('time');
var element = document.getElementById(url);
$(element).find(COUNT_CONTAINER_REF).text(time);
}
for(var i = 0; i < entries.length ; i + + ) {
var url = entries[i];
var element = document.getElementById(url);
var countSpan = $(element).find(COUNT_CONTAINER_REF);
if( countSpan.text() == '') {
countSpan.text(0);
}
}
})
.fail(function (object, error) {
console.log("Error: " + error.code + " " + error.message);
});
}
function addCount(Counter) {
var $visitors = $(".leancloud_visitors");
var url = $visitors.attr('id').trim();
var title = $visitors.attr('data-flag-title').trim();
var query = new AV.Query(Counter);
query.equalTo("url", url);
query.find({
success: function(results) {
if (results.length > 0) {
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 >
< / body >
< / html >
