SB2019021131 - Fedora 29 update for flatpak

Description

This security bulletin contains information about 2 secuirty vulnerabilities.

1) Privilege escalation (CVE-ID: CVE-2019-5736)

The vulnerability allows a remote attacker to gain elevated privileges.

The weakness exists in the runc container runtime due to file-descriptor mishandling, related to /proc/self/exe. A remote attacker can leverage the ability to execute a command as root within one of these types of containers: (1) a new container with an attacker-controlled image, or (2) an existing container, to which the attacker previously had write access, that can be attached with docker exec, overwrite the host runc binary with minimal user interaction and execute arbitrary code with root privileges.

Successful exploitation of the vulnerability may result in system compromise.

2) Privilege escalation (CVE-ID: CVE-2019-8308)

The vulnerability allows an adjacent attacker to escalate privileges on the system.

The vulnerability exists due an error when handling file descriptors related to /proc/self/exe. An adjacent attacker can trick the victim with root privileges into installing a system-wide Flatpak application that has an apply_extra script, and then run the apply_extra script in a sandbox with /proc mounted to escape sandbox protections and maliciously modify executable files as root on the host system.

Remediation

Install update from vendor's website.

References

• https://bodhi.fedoraproject.org/updates/FEDORA-2019-fd9345f44a