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Archive for July, 2010

The Microsoft LNK / USB worm / rootkit ‘issue’ will kill WIN XP SP2 and WIN2000 earlier…

Just recently, reports were released about a new kind of malware propagating through removable drives. The said malware exploits a newly-discovered vulnerability in shortcut files, which allows random code to be executed on the user’s system. Microsoft has officially acknowledged the vulnerability and released a security advisory.

The malware some of the AV industry detects as Win32/Stuxnet, unfortunately, is a worm (and rootkit) of a slightly different colour. It can propagate making use of a 0-day vulnerability described here and also listed by CVE as CVE-2010-2568.
The biggest problem is that Windows (specifically, the Windows Shell) can be tricked into executing malicious code presented in a specially-crafted shortcut (.LNK) file linking, in turn, to a malicious DLL (Dynamic Link Library).

The problem is in the way that Windows Shell fails to parse the shortcut correctly when it loads the icon, it isn’t necessary to click the icon for the malicious code to be executed! The code will be executed without any action on the part of the user once that folder is opened to access whatever legitimate files are on the device.