Hylafax: Insecure temporary file creation in xferfaxstats script

Background

Hylafax is a client-server fax package for class 1 and 2 fax modems.

Description

Javier Fernandez-Sanguino has discovered that xferfaxstats cron script supplied by Hylafax insecurely creates temporary files with predictable filenames.

Impact

A local attacker could create symbolic links in the temporary file directory, pointing to a valid file somewhere on the filesystem. When the xferfaxstats script of Hylafax is executed, this would result in the file being overwritten with the rights of the user running the script, which typically is the root user.

Workaround

There is no known workaround at this time.

Resolution

All Hylafax users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose net-misc/hylafax