According to an IDG report, users on forum boards started signaling the problem on Saturday evening. The complainants said several Windows files, and the security vendor's own program files, were identified as "Trojan.FakeAlert.5" malware after they performed an update for their BitDefender AV programs.
In an e-mail update Monday to ZDNet Asia, Vitor Souza, BitDefender's global communications director, explained that "multiple" BitDefender and Windows files which comprise .exe, .dll and other binary files, were incorrectly detected as malware and "moved to quarantine".
The faulty updates were applied to the company's home user product line as well as BitDefender Business Client and BitDefender Security for File Servers. Those using BitDefender's products from 2008 to 2010, on Windows XP, Windows Vista and Windows 7 platforms, were affected.
"By 11am PST, our team had reversed the faulty update so no additional users would be affected," Souza said, adding that the number of customers that contacted the company's support channels were "in the hundreds".
In a blog reply posted on Saturday, BitDefender had offered workarounds for BitDefender 2009 and BitDefender 2010 products, but has yet to release a patch for its 2008 version.
For more on this story, read Bad security update brings down PCs worldwide on ZDNet Asia.