"Mozilla warned Wednesday that a malicious program inserted
adware code into a Firefox plugin that has been downloaded
thousands of times over the past three months.
"Because of a virus infection, the Vietnamese language pack for
Firefox 2 was polluted with adware, Mozilla security chief Window
Snyder said in a blog posting. 'Everyone who downloaded the most
recent Vietnamese language pack since February 18, 2008 got an
infected copy,' she wrote. 'Mozilla does virus scans at upload time
but the virus scanner did not catch this issue until several months
after the upload...'"