More than two years after Blaster turned the summer of 2003 into an IT administrator’s worst nightmare, the worm is still very much alive and there are fears within Microsoft that thousands of Windows machines will never be completely dewormed.
According to statistics culled from Microsoft’s Windows malicious software removal tool, between 500 and 800 copies of Blaster are removed from Windows machines per day.
“The continued prevalence of [Blaster] is likely due to infected computers which, for one reason or another, will never be updated or disinfected. These computers will serve as eternal carriers for the worm,” says Matthew Braverman, a program manager in Microsoft’s Anti-Malware Engineering Team, the unit at Redmond responsible for updating the free worm-zapping tool.
In a case study on Blaster presented to the Virus Bulletin conference in October, Braverman said Blaster ranked in the top five of the most prevalent worms removed by the anti-malware utility, which ships on Patch Tuesday every month.
Braverman said 79 percent of the removals were made from Windows XP Gold and 21 percent from Windows XP SP1.
On Windows XP SP2, infections are almost nonexistent, Braverman said, pointing out that XP SP2 systems went through a major post-Blaster security overhaul that means those systems cannot be infected through Blaster’s main replication vector.
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