Red Hat Bugzilla – Bug 23169
exmh follows symlinks when writing to /tmp/exmhErrorMsg
Last modified: 2007-03-26 23:38:47 EDT
From: "Stanley G. Bubrouski" <stan@CCS.NEU.EDU>
Subject: Advisory: exmh symlink vulnerability
Date: Sun, 31 Dec 2000 15:32:40 -0500
Author: Stan Bubrouski (firstname.lastname@example.org)
Date: December 31, 2000
Versions affected: 2.2 and probably previous versions.
Severity: A malicious local user could use a symlink attack to overwrite
any file writable by the user executing exmh.
Problem: When exmh detects a problem at startup (or possibly other times,
I don't have time to investigate) it encounters errors in its code or
configuration an error dialog comes up asking the user what happened and
giving them the option to fill in an explanation and click a button to
send the bug report via e-mail to the maintainer. If the user does
attempt to e-mail the maintainer a file named /tmp/exmhErrorMsg is created
and if the file exists and is a symlink it will follow the symlink
allowing local files to be overwritten depending on the user running exmh.
Solution: There are no known solutions at this time.
Copyright 2000 Stan Bubrouski
Stan Bubrouski email@example.com
316 Huntington Ave. Apt #676, Boston, MA 02115 (617) 377-7222
I tried this on Red Hat 6.x machines also and it produced similar bad behaviour,
following symlinks that is.