Full Disclosure mailing list archives
Re: /bin/rm file access vulnerability
From: Jörg Eschke <joerg () eschke net>
Date: Thu, 30 Dec 2004 12:44:59 +0100
Sure, a user with admin rights is able to access/delete every local file, regardless of the specific filepermissions. Your 'exploit' will work with e.g. /bin/cat as well. But i can't see a vulnerability anyway. Am i missunderstanding something ? Am Do, den 30.12.2004 schrieb Lennart Hansen um 2:18:
/bin/rm file access vulnerability Affected Products: /bin/rm (all versions, tested on FreeBSD and linux) (http://www.freebsd.org http://www.kernel.org) Author: Xenzeo (Ablazed, Ultralaser, Lennart A. Hansen) xenzeo at blackhat dot dk /bin/rm is a program that removes the named file arguments on unix systems. When /bin/rm is called it checks the file's permissions and the id of the user trying to remove the file. If the user does not have the required permissions to delete the file, /bin/rm will simply reject and exit. However, it is possible for a person with admin rights (root) to delete _any_ file on the system regardless of who has created it and what it's permissions are. Proof of concepts: $ touch /home/xenzeo/file $ ls -l /home/xenzeo/file -rw-r--r-- 1 xenzeo none 0 Dec 30 2004 /home/xenzeo/file $ id uid=1000(xenzeo) gid=513(none) groups=513(none),545(users) $ su -c 'rm -f /home/xenzeo/file' $ ls -l /home/xenzeo/file ls: file: No such file or directory #!/usr/bin/perl if ($#ARGV != 0) { die "usage: rm-exploit.pl file\r\n"; } else { $file = $ARGV[0]; print "*** CMD: [ /bin/rm -f $file ]\r\n"; print "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\r\n"; if ($> == 0) { print "[-] EXECUTING CMD\r\n"; system("/bin/rm -f $file"); print "[-] DONE\r\n"; print "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\r\n"; exit(); } else { print "[-] EXPLOIT FAILED\r\n"; print "[-] YOU ARE NOT ROOT\r\n"; print "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\r\n"; } } Vender status: Neither FreeBSD nor Linux developers have been contacted yet! -Xenzeo
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Current thread:
- /bin/rm file access vulnerability Lennart Hansen (Dec 30)
- Re: /bin/rm file access vulnerability Eric Romang / ZATAZ (Dec 30)
- Re: /bin/rm file access vulnerability Michal Zalewski (Dec 30)
- Re: /bin/rm file access vulnerability Jörg Eschke (Dec 30)
- Re: /bin/rm file access vulnerability shane milton (Dec 30)
- Re: /bin/rm file access vulnerability Raymond Morsman (Dec 31)