Ed Felten of Freedom to Tinker comments:
Josh wrote recently about a serious security bug that appeared in Debian Linux back in 2006, and whether it was really a back door inserted by the NSA. (He concluded that it probably was not.)
Today I want to write about another incident, in 2003, in which someone tried to backdoor the Linux kernel. This one was definitely an attempt to insert a backdoor. But we don’t know who it was that made the attempt–and we probably never will.
A fascinating look at how a backdoor might be introduced into a source tree branch. And the power of open source. Visibility kept this from happening a decade ago. What to say it didn’t happen elsewhere?
Read more at: The Linux Backdoor Attempt of 2003