More NetSky worms. So much for quitting

Two new NetSky worms appeared on the scene yesterday, despite a promise by the original author this week to refrain from releasing any more versions.

Differences in the code of NetSky-L and NetSky-M from their 11 older siblings have led anti-virus researchers to suspect that they are the work of a copycat. This suggests the source code of the virus has been leaked.

Text hidden inside NetSky-K said that it would be "the last version", but warned that the source code would be "available soon". Releasing the source code would make it far easier for other viruswriters to create new versions of the worm, such as NetSky-L.

Like previous versions, Netsky-L, spreads by email in an attachment. But it contains a number of significant differences from its predecessors.

Carole Theriault, a security consultant at AV firm Sophos, told El Reg that unlike earlier variants, Netsky-L contains no mention of 'Skynet', does not try and disinfect the Bagle worm, and contains no hidden text slagging off Bagle's author.

It could be the NetSky author is just playing games and hasn't quit at all. Theriault considers this as possible but unlikely even though she acknowledges that her tentative conclusions are based on circumstantial evidence.

Security watchers are yet to confirm the release of the source code of NetSky but if the original author has kept to his promise and released blueprints for the virus then this might result in the creation of more mutations.. And these might come at an even faster rate if more people have access to plans on how NetSky is built.

AV firms rate NetSky-L, which is spreading slowly, as low risk. NetSky-M is even rarer. Previous versions of the worm - in particular NetSky-D - remain a far more potent threat. ®

Related stories

NetSky author signs off
War of the worms turns into war of words
Netsky-D makes your PC go beep, beep, beep
MyDoom and Netsky cause chaos