Debian update for flatpak

1) Privilege escalation

EUVDB-ID: #VU17726

Risk: Low

CVSSv3.1: 6.6 [CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2019-8308

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

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.

Mitigation

Update the affected package to version: 0.8.9-0+deb9u2.

Vulnerable software versions

flatpak (Debian package): 0.8.9-0+deb9u1 - 0.8.9-0+deb9u1~bpo8+1

External links

http://www.debian.org/security/2019/dsa-4390

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.