am-utils: Insecure temporary file creation

Background

am-utils is a collection of utilities for use with the Berkeley Automounter.

Description

Tavis Ormandy discovered that, when creating temporary files, the ‘expn’ utility does not check whether the file already exists.

Impact

A local attacker could exploit the vulnerability via a symlink attack to overwrite arbitrary files.

Workaround

There is no known workaround at this time.

Resolution

All am-utils users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-fs/am-utils-6.1.5"