OpenAFS: Privilege escalation

Background

OpenAFS is a distributed network filesystem.

Description

Benjamin Bennett discovered that the OpenAFS client contains a design flaw where cache managers do not use authenticated server connections when performing actions not requested by a user.

Impact

If setuid is enabled on the client cells, an attacker can supply a fake FetchStatus reply that sets setuid and root ownership of a file being executed. This could provide root access on the client. Remote attacks may be possible if an attacker can entice a user to execute a known file. Note that setuid is enabled by default in versions of OpenAFS prior to 1.4.4.

Workaround

Disable the setuid functionality on all client cells. This is now the default configuration in OpenAFS.

Resolution

All OpenAFS users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-fs/openafs-1.4.4"