Bugtraq mailing list archives
Re: bin owned system files
From: wam () fedex com (William McVey)
Date: Fri, 26 Jul 1996 13:48:04 -0500
"Robert E. Adams" wrote:
Are there any known problems/bugs/etc. with "root" executing system binaries owned by "bin" as long as the "bin" account is disabled in /etc/passwd. (i.e. * for password and /bin/false for the shell).
In addition to the problems with bin ownership as it relates to NFS, there are some other issues as well. It all boils down to the principle that under UNIX, the system has a single privileged account. To protect this account the system designers have placed features into UNIX to better protect the root account. These features do not exist for other "system accounts" such as sys, bin, lp, and the like. By having files that root runs owned by the 'bin' owner, you are basically putting the security of the privileged but better protected root account at the mercy of not as protected account. Some of these extra protections include: NFS mapping of uid 0 to nobody (already mentioned) special handling in ruserok() (hosts.equiv doesn't apply to root) secure tty login restrictions (root logins restricted to console) must be a member of group 0 to su to root (on some systems) Various systems have other additional protections for root. A very good tool for detecting what executables, shared libraries, and config files are being executed by root but not owned by root is the check_embedded script in the tiger distribution. Tiger can be found on net.tamu.edu and I'm sure a mirror exists at coast.cs.purdue.edu (thanks Spaf). -- William McVey Federal Express
Current thread:
- bin owned system files Robert E. Adams (Jul 25)
- ? Trojan /usr/bin/false ? Jeremy Brinkley (Jul 25)
- Re: ? Trojan /usr/bin/false ? Elliot Lee (Jul 25)
- Re: bin owned system files Gene Spafford (Jul 25)
- Re: bin owned system files Colin Jenkins (Jul 26)
- Re: bin owned system files Gene Spafford (Jul 26)
- Re: bin owned system files Jungseok Roh (Jul 26)
- <Possible follow-ups>
- Re: bin owned system files William McVey (Jul 26)
- Re: bin owned system files dsiebert () icaen uiowa edu (Jul 26)
- Re: bin owned system files Bruce Barnett (Jul 26)
- ? Trojan /usr/bin/false ? Jeremy Brinkley (Jul 25)