Famous Trojan (Score 1)

Back in the seventies, Dennis Ritchie (father of "C") created a Trojan Horse that he slipped into one of the early UNIX releases at Bell Labs. It involved the C compiler recognizing that it was compiling login.c (the kernel routine for user logon) and added code to it to allow a back-door entry. But this was just a bootstrap. The real cleverness was to create a binary of the compiler that recogognized it was building the compiler, in which it inserted code to recognize login.c (and, of course, to insert itself in the new binary). Now despite a source distribution, the Trojan Horse was able to be distributed in a "source" distribution.