Remarkably, with the new operating system new operating system just released to business, the software giant said in effect that there is nothing it can do about the threats in question -- Stratio-Zip, Netsky-D and MyDoom-O - because they rely on social engineering to invade systems. The three threats together account for 39.7% of currently circulating malware, according to Sophos.
"Based on our initial investigation, Microsoft can confirm that these variants do not take advantage of a security vulnerability, rather they rely on social engineering to infect a user's system," Microsoft said in a statement.
While the email system built into Vista, Windows Mail Client, stops all of the top 10 viruses identified by Sophos for November, the three threats outlined can infect systems when a third-party email client is used, Sophos said last week. Stratio-Zip was November's top malware, accounting for one-third of virus traffic, Sophos said.
Sophos said that while no Vista-specific viruses have yet been detected, they are likely to appear soon. "It won't be long before cyber criminals develop Vista-specific malware or modify current threats to fit the bill," said Ron O'Brien, Sophos senior security analyst, in a statement. "The Stratio-Zip worm, for example, remains on the top ten list due to constant, minor alterations to its code that force security systems to re-identify the malware."
Few actual installations of Vista currently exist, since the operating system was only launched on 30 November. Sophos and McAfee have antivirus products ready for Vista, but Symantec, Trend Micro and CA are still working on theirs.
Microsoft congratulated itself on the "aggressive security design decisions" it took with Windows Mail Client, but said if users choose to use other, more vulnerable email programs they can configure User Account Control (UAC) to help limit the damage users can cause if they are infected.