, like many big programs written for multi-user computers, was partially developed at a university, with little faculty supervision.
Programmers also had to modify the electronic mail program and the Berkeley Unix
4.3's other affected features to thwart future attacks, enabling network links to be made again.
We want Berkeley UNIX." So we looked at Berkeley UNIX and what some other companies had done with it and we realized that there is a fundamental problem with some of the UNIX architectures out there.
It's totally compatible with Berkeley UNIX. And, again, Mach came from the university research communities.
We couldn't have built the operating system team we did if we were doing standard Berkeley UNIX like some other people.
The user-level networking features in Berkeley UNIX are formulated around the concepts of remote execution and trusted host.
On most Berkeley UNIX systems, it is routine for an experienced programmer to be able to trick a privileged system program into executing nonstandard versions of system commands.
On the distribution tape of 4.2BSD (a version of Berkeley UNIX), it happens that the directory named "/usr/spool/at" is universally writeable by all users; it also happens that it is fairly easy to trick the operating system into executing privileged commands by storing them in that directory.
Joy received the 1986 ACM Grace Murray Hopper Award for his work on the Berkeley UNIX