Funny how the article says Ken Thompson popularized the attack. There's good reason to say he invented it.
Although Ken Thompson is responsible for popularising the idea through his Turing award speech in 1984.
Edit: Ken Thompson mentions the paper in the acknowledgements of his Turing award speech.
""" Acknowledgment. I first read of the possibility of such a Trojan horse in an Air Force critique [4] of the security of an early implementation of Multics. I cannot find a more specific reference to this document. I would appreciate it if anyone who can supply this reference would let me know. """
Always neat to have lost sources show up eventually. Librarians rule.