Shorewall : Insecure temp file handling

Background

Shorewall is a high level tool for configuring Netfilter, the firewall facility included in the Linux Kernel.

Description

Shorewall uses temporary files and directories in an insecure manner. A local user could create symbolic links at specific locations, eventually overwriting other files on the filesystem with the rights of the shorewall process.

Impact

An attacker could exploit this vulnerability to overwrite arbitrary system files with root privileges, resulting in Denial of Service or further exploitation.

Workaround

There is no known workaround at this time. All users should upgrade to the latest available version of Shorewall.

Resolution

All users should upgrade to the latest available version of Shorewall, as follows:

 # emerge sync
 
 # emerge -pv ">=net-firewall/shorewall-1.4.10f"
 # emerge ">=net-firewall/shorewall-1.4.10f"