Permissions, Privileges, and Access Controls in Snapd - CVE-2019-7303

Vulnerability identifier: #VU18064

CSH Severity: Low

CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2019-7303

CWE-ID: CWE-264

Exploitation vector: Local access

Exploit availability: No public exploit available

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.

Snapd
snapd (Ubuntu package)

Install updates from vendor's website.

Snapd - update to 2.37.4
snapd (Ubuntu package) - addressed in versions 2.37.4ubuntu0.1, 2.37.4~14.04.1, 2.37.4+18.04.1, 2.37.4+18.10.1

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

• Security restrictions bypass in snapd
• Ubuntu update for snapd