Security restrictions bypass in snapd

1) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU18064

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: CVE-2019-7303

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

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists due to incorrect implementation of the snapd default seccomp filter for strict mode snaps blocks on 64-bit systems that was supposed to prevent the use of the TIOCSTI ioctl. A malicious snap can bypass intended access restrictions and insert characters into the terminal’s input queue.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Snapd: 2.28 - 2.37.3

External links

http://usn.ubuntu.com/3917-1/
http://bugs.launchpad.net/snapd/+bug/1812973
http://people.canonical.com/~ubuntu-security/cve/2019/CVE-2019-7303.html

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.