unp: Arbitrary command execution

Background

unp is a script for unpacking various file formats.

Description

Erich Schubert from Debian discovered that unp does not escape file names properly before passing them to calls of the shell.

Impact

A remote attacker could entice a user or automated system to unpack a compressed archive with a specially crafted file name, leading to the execution of shell commands from within the filename. That code will be executed with the privileges of the user running unp.

Workaround

There is no known workaround at this time.

Resolution

All unp users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=app-arch/unp-1.0.14"