Zeus bot latches onto Windows shortcut security hole

bLNKing hell

Miscreants behind the Zeus cybercrime toolkit and other strains of malware have begun taking advantage of an unpatched shortcut handling flaws in Windows. It was first used by a sophisticated worm to target SCADA-based industrial control and power plant systems.

Isolated strains of mainstream malware that took advantage of how the zero-day Windows flaw first exploited by the sophisticated Stuxnet worm began appearing late last week. The same approach has since been applied by the dodgy sorts behind Zeus, a family of sophisticated toolkits frequently used to steal bank login credentials and the like from compromised systems.

Security firm F-Secure reports the appearance of strains of Zeus that take advantage of the same security hole exploited by the Stuxnet worm. Zeus-contaminated emails pose as security messages from Microsoft, containing contaminated ZIP file attachments laced with a malicious payload that utilises the lnk flaw to infect targeted systems.

Several additional malware families have also latched onto the same Windows shortcut trick including Sality, a popular polymorphic virus. Trend Micros confirms the appearance of the exploit vector in variants on Zeus and Sality while McAfee adds that the VXers behind the Downloader-CJX Trojan have also begun feasting off the shortcut security bug.

A greater volume of malware targeting the same Windows security hole is almost inevitable.

Fortunately virus writers are, thus far at least, using the same basic exploit method, a factor that makes it easier for security firms to block attacks.

Microsoft is advising users to apply temporary workarounds while its security researchers investigate the shortcut flaw, a process likely to eventually result in a patch.

In the meantime, security firm Sophos has developed Windows shortcut exploit protection tool, which is available at no cost to sys admins, whatever variant of anti-virus they utilise. ®

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