Ouch, indeed. We ended up getting lucky and found a workstation where someone had left themselves at a root prompt on another machine that had a shared NFS mount. This was before protection from this kind of attack, so we were able to create a setuid root script and run it on the main server to get root access to fix the broken passwd file.

Our next step was going to be rebooting the server. We were pretty sure that faced with a corrupt passwd file, SunOS would drop to single user mode. Never tested that theory. Glad we didn't have to, the server in question was a hack job as it was. Copied over (literally, as files) from a previous server, it wasn't even 100% in agreement with itself on its own hostname, so I always kinda wondered how it would react to any big changes.

I've seen it written *nix to grab Linux and Unix.