The SANS Institute warned IT system administrators to be wary of an update to CA's anti-virus software that causes the software to classify an element of Windows 2003 as malware.
Experts with SANS warned last week that administrators were experiencing Windows 2003 server crashes after updating with a defective signature for CA's eTrust software that identifies Lsass.exe files as the Lassrv-B Trojan.
The crashes were caused by the deletion of the LSASS Windows Service component by the software, which also prevented administrators from rebooting.
"It seems that CA accidentally flagged Lsass.exe as a bad file," wrote Joel Esler of SANS. "(It is) reminiscent of the McAfee .xls debacle of not too long ago."
CA issued a fixed update, but some businesses are still dealing with systems disabled by the initial problem. Both CA and Microsoft have published advisories with instructions to restore Windows 2003 systems.