runC: Privilege escalation

Background

RunC is a CLI tool for spawning and running containers according to the OCI specification.

Description

A vulnerability was discovered in runC that allows additional container processes via ‘runc exec’ to be ptraced by the pid 1 of the container. This allows the main processes of the container, if running as root, to gain access to file-descriptors of these new processes.

Impact

An attacker, who is able to successfully escape the container or modify runC’s state before process initialization, could escalate privileges.

Workaround

There is no known workaround at this time.

Resolution

All runC users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=app-emulation/runc-1.0.0_rc2-r2"