Concerned about recent PAN-OS and other firewall/VPN CVEs? Take advantage of Zscaler’s special offer today

Zscaler Blog

Get the latest Zscaler blog updates in your inbox

Security Research

Mass Compromise Includes ComputerWorld MX

July 02, 2012 - 2 min read

We were alerted to this from a customer reporting that Zscaler was blocking pages on

And as evidence of this, was our Zulu report - which when we looked at it showed that the page itself did not have any malicious content / reason
But the site's own internal JS files were being flagged as malicious, e.g., tabber.js as a result of Zscaler's threat fingerprinting.
Looking at the JS files, there was the addition of obfuscated JS at the end of the flagged files:
The JS makes use of the DOM to avoid automated deobfuscation, e.g., JSUnpack failed for me.  Deobfuscating, shows a number of things
  • For one, the author of the malware used Windows (you can see the carriage-return newlines as ctrl-v ctrl-M in my vi editor)
  • The malicious JS utilizes the setTimeout function, so that the malicious injection only occurs after being on the page for 500 miiliseconds - which can help evade rapid, automated analysis of pages
  • The malicious JS injects an IFrame using a domain generation algorithm (DGA) based on time (changes about every 40,000 milliseconds or so)
Looping through the DGA, these are some of the domains:
Many of the pages are already blocked by Google SafeBrowsing:
Looks like this is all tied to an on-going campaign from mid/late June (e.g., Pastebin paste with some of the domains on June 21) and an earlier blogpost suggesting that these compromises came from the Plesk File Manager.
form submtited
Thank you for reading

Was this post useful?

dots pattern

Get the latest Zscaler blog updates in your inbox

By submitting the form, you are agreeing to our privacy policy.