Researchers at Matousec have discovered a new and particularly worrisome flaw in the Windows ecosystem that allows malware to completely bypass security software.
Anti-virus software works by standing between applications and the Windows kernel, inspecting code before it has a chance to execute. Matousec passes benign code through a security suite, thus clearing the way for a program to run, and then swaps it out for malicious code after it passes inspection. The flaw affects nearly every piece of security software on the market, including Norton, McAfee, AVG, Kaspersky and F-Secure. (The entire list of vulnerable software can be found at the end of Matousec's report here:
http://www.matousec.com/info/articles/khobe-8.0-earthquake-for-windows-desktop-security-software.php#table-of-vulnerable-software ) While researchers only tested the vulnerability against 32-bit versions of Windows XP and Vista, the company says that 64-bit versions of those operating systems, as well as Windows 7, are also at risk.
The only anti-virus tool confirmed to be immune to the attack is the appropriately named Immunet:
http://www.immunet.com/ , but that doesn't mean you should immediately jump ship to its product. For the moment, there is no known malware that exploits this security hole. Additionally, it is particularly difficult to exploit in Vista and Windows 7 PCs due to an extra layer of protection called PatchGuard. But perhaps the biggest hurdle to hackers taking advantage of what has been dubbed an "argument-switch attack" is that it can only be executed by malware that has already snuck past a computer's defenses.
The "argument-switch attack" won't give hackers some new way to steal your data, but it does give them a way to open the floodgates once they've already gained access. As always, the best defense is to keep your software up-to-date, and to avoid risky online behavior. Because the flaw is particularly serious for XP users, this is just one more reason to upgrade to Windows 7.
(Switched)
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, but I was expect that both PCs are clean 
, did you use Immunet with some other AV or it's your only protection from Malware??
I never heard for Vipre AntiVirus.