Many enterprises, including police departments and hospitals in the US, were hit by a false positive from McAfee on Wednesday that labelled a core Windows file as potentially malign.
A detection update from McAfee (DAT 5958) falsely labelled the svchost.exe as the Wecorl-A virus, sending a core Windows system file into quarantine in the process. Infected computers became inoperable and went into a continuous reboot cycle. Clean up operations were further complicated by the fact that the dodgy update disabled network access.
Full story: Rogue McAfee update strikes police, hospitals and Intel -The Register