Arbitrary file deletion in flatpak

1) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU66718

Risk: Low

CVSSv3.1: 2.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: N/A

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

Exploit availability: No

Description

The vulnerability allows a local user to delete arbitrary files on the system.

The vulnerability exists due to usage of an old version of libostree, which lacks filtration of ref (branch) names. A local user can force the latpak-system-helper service to delete arbitrary files by requesting deletion of a crafted ref (branch) name.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Flatpak: 0.2.1 - 0.10.1

ostree: 2017.1 - 2017.12

External links

http://github.com/flatpak/flatpak/security/advisories/GHSA-45jq-5658-v38x
http://github.com/ostreedev/ostree/pull/1286

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.