4 ms·

Many years ago (decades, in fact) as a fresh new excuse for a unix admin, I needed to hide the passwd binary so that users couldn't find it and change their loc

Many years ago (decades, in fact) as a fresh new excuse for a unix admin, I needed to hide the passwd binary so that users couldn't find it and change their local password on the terminal box (this was early ISP days). SunOS 4.1.4, as I recall. Anyway, I hid that binary. In /etc, where they'd never think to look. Gosh we do some dumb things, eh? LOL. That took a while to find a solution for, and no small amount of luck. The owner of the ISP walked back in the office a couple hours later and said "I heard you had some excitement?" I said, "Oh yes, it was pretty ugly for a bit." "Is it fixed now?" "Yup." "Carry on." For sure thought my ass was fired and I'd only been on the job a month or so.

Nextgrid 5y ago
I don't get it - how would moving that binary break a running system? Is that binary somehow involved in something else beyond password changes?
- krylon 5y ago
  /etc/passwd contains the user database on most Un*x systems. GP replaced it with the executable file, thus wiping out the system's users. Ouch.
  - rootusrootus 5y ago
    > Ouch. 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.
  - unethical_ban 5y ago
    Why did you write it Un*x? Is there a Unex or Unox? I've seen it written *nix to grab Linux and Unix.
    - rootusrootus 5y ago
      That has precedent going way back, at least 34 years: https://unix.stackexchange.com/questions/2342/why-is-there-a-when-there-is-mention-of-unix-throughout-the-internet https://unix.stackexchange.com/questions/2342/why-is-there-a... Doesn't explain why exactly the asterisk was put in that particular position. Maybe someone felt like it was odd to lead the word with an asterisk. :shrug:
      - wiml 5y ago
        The asterisk is there to avoid writing the word out in full, like "G*d" or "f*ck". There was a time when Unix[1][2] was a trademarked name and if you used it you had to attribute it. If you wanted to refer to the general family of Unix/POSIX/SysV/BSD/etc systems, you might be tempted to write "Unix"[1][2], but to avoid the presumably-Sauron[3]-like eye of the trademark holders, you'd bowdlerize it a little. [1] Unix is a registered trademark of AT&T Bell Labs. [2] Unix is a registered trademark of The Open Group. [3] Sauron is a registered trademark of Tolkien Enterprises
    - luke2m 5y ago
      Linix?
  - Nextgrid 5y ago
    My bad. I somehow expected him to put it into /etc and rename it to something else. Indeed if he overwrote /etc/passwd then all hell would break loose.

Nextgrid 5y ago

I don't get it - how would moving that binary break a running system? Is that binary somehow involved in something else beyond password changes?

krylon 5y ago
/etc/passwd contains the user database on most Un*x systems. GP replaced it with the executable file, thus wiping out the system's users. Ouch.
- rootusrootus 5y ago
  > Ouch. 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.
- unethical_ban 5y ago
  Why did you write it Un*x? Is there a Unex or Unox? I've seen it written *nix to grab Linux and Unix.
  - rootusrootus 5y ago
    That has precedent going way back, at least 34 years: https://unix.stackexchange.com/questions/2342/why-is-there-a-when-there-is-mention-of-unix-throughout-the-internet https://unix.stackexchange.com/questions/2342/why-is-there-a... Doesn't explain why exactly the asterisk was put in that particular position. Maybe someone felt like it was odd to lead the word with an asterisk. :shrug:
    - wiml 5y ago
      The asterisk is there to avoid writing the word out in full, like "G*d" or "f*ck". There was a time when Unix[1][2] was a trademarked name and if you used it you had to attribute it. If you wanted to refer to the general family of Unix/POSIX/SysV/BSD/etc systems, you might be tempted to write "Unix"[1][2], but to avoid the presumably-Sauron[3]-like eye of the trademark holders, you'd bowdlerize it a little. [1] Unix is a registered trademark of AT&T Bell Labs. [2] Unix is a registered trademark of The Open Group. [3] Sauron is a registered trademark of Tolkien Enterprises
  - luke2m 5y ago
    Linix?
- Nextgrid 5y ago
  My bad. I somehow expected him to put it into /etc and rename it to something else. Indeed if he overwrote /etc/passwd then all hell would break loose.