Original URL: http://www.theregister.co.uk/2012/07/16/symantec_update_snafu/

Symantec update killed biz PCs in three-way software prang

Encryption, cache and antivirus in head-on crash

By John Leyden

Posted in Security, 16th July 2012 14:34 GMT

Symantec has apologised after an update to its security software sparked repeated crashes on enterprise Windows XP machines.

The antivirus giant withdrew the misfiring definition update, issued on 11 July, hours after problems first appeared, releasing a revised update the next day. No new issues have been reported since this signature rollback was applied.

Subsequent analysis has revealed that a three-way clash between third-party encryption drivers, Symantec's own security software and the Windows XP Cache manager resulted in the infamous Blue Screen of Death (BSOD) on vulnerable machines, as this advisory explains:

The root cause of the issue was an incompatibility due to a three-way interaction between some third-party software that implements a file system driver using kernel stack based file objects – typical of encryption drivers, the SONAR signature and the Windows XP Cache manager.  The SONAR signature update caused new file operations that create the conflict and led to the system crash.

The glitch is specific to the Symantec Endpoint Protection Small Business Edition (SEP SBE) 12.1, Symantec Endpoint Protection (SEP) 12.1 and Symantec Endpoint Protection.cloud (SEP.cloud). Corporate users of other version of Symantec’s Enterprise security products weren't affected - nor were ordinary punters.

Symantec is reviewing its quality-assurance process to improve compatibility testing, a move it hopes will safeguard against similar snafus in future.

Bugs involving antivirus signature updates crop up from time to time regardless of the vendor. Even though testing processes are improving, the sheer volume of updates software makers are obliged to push out means that testing isn't exhaustive as one might hope, and problems are almost certain to occur.

Release managers can only make sure these cock-ups happen as infrequently as possible rather than expending huge amounts of effort trying to prevent them entirely. ®