Ubuntu Security Notice USN-2455-1
7th January, 2015
bsd-mailx vulnerability
A security issue affects these releases of Ubuntu and its
derivatives:
- Ubuntu 14.10
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS
- Ubuntu 10.04 LTS
Summary
bsd-mailx could be made to run programs if it parsed a specially crafted
email address.
Software description
- bsd-mailx
– simple mail user agent
Details
It was discovered that bsd-mailx contained a feature that allowed
syntactically valid email addresses to be treated as shell commands. A
remote attacker could possibly use this issue with a valid email address to
execute arbitrary commands.
This functionality has now been disabled by default, and can be re-enabled
with the “expandaddr” configuration option. This update alone does not
remove all possibilities of command execution. In environments where
scripts use mailx to process arbitrary email addresses, it is recommended
to modify them to use a “–” separator before the address to properly
handle those that begin with “-“.
Update instructions
The problem can be corrected by updating your system to the following
package version:
- Ubuntu 14.10:
-
bsd-mailx
8.1.2-0.20131005cvs-1ubuntu0.14.10.1
- Ubuntu 14.04 LTS:
-
bsd-mailx
8.1.2-0.20131005cvs-1ubuntu0.14.04.1
- Ubuntu 12.04 LTS:
-
bsd-mailx
8.1.2-0.20111106cvs-1ubuntu0.1
- Ubuntu 10.04 LTS:
-
bsd-mailx
8.1.2-0.20090911cvs-2ubuntu1.1
To update your system, please follow these instructions:
https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system update will make all the necessary changes.