Google has blamed human error for a bug that found every search result was malware.
From 6:30AM until 7:25AM PST last Saturday, every Google search result was accompanied by the message "this site may harm your computer".
The error was caused when a Google employee accidentally added a URL of "/" to Google's list of sites suspected of spreading malware, which is maintained in collaboration with the non-profit organization StopBadware.org, states a post on the official Google blog. The character "/" acts as a wildcard.
"This was clearly an error, and we are very sorry for the inconvenience caused to our users," wrote Marissa Mayer, Google's VP of search products. "Fortunately, our on-call site reliability team found the problem quickly and reverted the file."
Due to Google's practice of staggering updates, each user was affected for around 40 minutes, Mayer said.
Each "attack site" message linked to a page on StopBadware.org containing more information on the blacklist. Millions of users clicked on that link, crashing the non-profit's servers in what was the accidental equivalent of a DDoS attack, the StopBadware blog states.
The snafu cost Google around $2-$3 million in lost advertising revenue and has left the world's top search engine red-faced, one expert toldthe Guardian.