Security Response

1. A rootkit wants to be able to run without restriction on a target computer. 
2. It wants to elude being detected by the computer or an installed security product. 
3. It wants to deliver its payload, such as stealing passwords or network bandwidth, or installing other malicious software.

In late September 2011, it was reported that a previously unknown and un-patched vulnerability in Hancom Office (a word processing software predominantly used in Korea) was exploited in the wild. We often hear of new exploits targeting software used worldwide and while these incidents tend to grab all the attention, we also encounter instances of regional software, which often have a limited user base becoming an exploit target. One example of a similar regional software that was also exploited in malware attacks is Ichitaro - a word processing software mostly used in government organizations and their associates in Japan. 

The group that initially discovered the original Duqu binaries, CrySyS, has since located an installer for the Duqu threat. Thus far, no-one had been able to recover the installer for the threat and therefore no-one had any idea how Duqu was initially infecting systems. Fortunately, an installer has recently been recovered due to the great work done by the team at CrySyS.

The installer file is a Microsoft Word document (.doc) that exploits a previously unknown kernel vulnerability that allows code execution. We contacted Microsoft regarding the vulnerability and they're working diligently towards issuing a patch and advisory. When the file is opened, malicious code executes and installs the main Duqu binaries. The chart below explains how the exploit in the Word document file eventually leads to the installation of Duqu.

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In recent days, we have seen blogs about a specific type of Mass Injection campaign. We take this opportunity to publish our findings in this blog.

This particular campaign has already picked up pace and it is infecting a lot of innocent users out there. It all starts with a script that is injected into certain sites. The script itself points to one particular site: “http://[REMOVED]/urchin.js”. Throughout this blog, we will see the different exploits that this particular campaign uses in order to install malicious files on to a compromised computer.

Upon visiting a site with the injected script, the user is redirected to a malicious site. A subsequent redirection takes the user to a site that contains an obfuscated script. When the script is decoded, it reveals an embedded iFrame tag. Below is an example of the de-obfuscated iFrame tag embedded in the site.

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