Stefan BohacekHm, #TIL about the "most widespread security incident in the history of the Web", when in 1999 a security flaw in Hotmail was revealed that permitted anybody to log in to any Hotmail account using the password "eh".
From the original source archived at https://web.archive.org/web/20140408200533/https://archive.wired.com/science/discoveries/news/1999/08/21503
"After examining that code early Monday, outside security experts suggested that the problem might have been a backdoor inadvertently left open on Hotmail servers by Microsoft engineers.
Microsoft vehemently denied the backdoor suggestions, and instead described the problem as "an unknown security issue.""
Dante@stefan "an unknown security issue."
"It's not a backdoor. Actually, we have no idea what it is." Great publicity!