AutoRun. Reloaded

Recent months have produced little of interest among worms written in Java and script languages such as JavaScript and VBScript. The main reason behind this was the limited proficiency of the virus writers, whose creations were anything but remarkable. However, a couple of malware samples grabbed our attention; their complexity is testimony to the fact that professionals sometimes get involved as well.

Kaspersky Lab’s products detect these special worms as Worm.JS.AutoRun and Worm.Java.AutoRun. They are also detected by heuristic methods as HEUR:Worm.Script.Generic and HEUR:Worm.Java.Generic respectively.

These two worms have three key features in common: heavy obfuscation, backdoor-type essential payloads, and similar methods of propagation. Both worms spread by copying themselves and the configuration file autorun.inf into the root folders of logical volumes of removable storage media and network disks. If these infected storages are opened on other computers, the infection can spread. Having infected the operating system and established a foothold on the victim computer, the malicious programs deploy their principal payload.

For months, the number of AutoRun worms detected on Kaspersky Lab users’ computers remained essentially unchanged. According to Kaspersky Security Network data, half of all script worms spread themselves this way. As for Java worms, this is not their usual method of propagation. However, in the last three months we have seen a dramatic rise in the number of new Worm.Java.AutoRun modifications.

Detection levels for unique script worms, AutoRun script worms, and heuristically detected AutoRun script worms April 2012 – May 2013

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Story added 13. June 2013, content source with full text you can find at link above.