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Ubuntu Security Notice USN-6125-1
May 31, 2023

snapd vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

• Ubuntu 23.04
• Ubuntu 22.10
• Ubuntu 22.04 LTS
• Ubuntu 20.04 LTS
• Ubuntu 18.04 LTS
• Ubuntu 16.04 LTS (Available with Ubuntu Pro)

Summary:

An intended access restriction in snapd could be bypassed by strict mode snaps.

Software Description:

• snapd: Daemon and tooling that enable snap packages

Details:

It was discovered that the snap sandbox did not restrict the use of the
ioctl system call with a TIOCLINUX request. This could be exploited by a
malicious snap to inject commands into the controlling terminal which would
then be executed outside of the snap sandbox once the snap had exited. This
could allow an attacker to execute arbitrary commands outside of the
confined snap sandbox. Note: graphical terminal emulators like xterm,
gnome-terminal and others are not affected - this can only be exploited
when snaps are run on a virtual console.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 23.04:
snapd 2.59.1+23.04ubuntu1.1

Ubuntu 22.10:
snapd 2.58+22.10.1

Ubuntu 22.04 LTS:
snapd 2.58+22.04.1

Ubuntu 20.04 LTS:
snapd 2.58+20.04.1

Ubuntu 18.04 LTS:
snapd 2.58+18.04.1

Ubuntu 16.04 LTS (Available with Ubuntu Pro):
snapd 2.54.3+16.04.0ubuntu0.1~esm6

In general, a standard system update will make all the necessary changes.

References:
https://ubuntu.com/security/notices/USN-6125-1
CVE-2023-1523

Package Information:
https://launchpad.net/ubuntu/+source/snapd/2.59.1+23.04ubuntu1.1
https://launchpad.net/ubuntu/+source/snapd/2.58+22.10.1
https://launchpad.net/ubuntu/+source/snapd/2.58+22.04.1
https://launchpad.net/ubuntu/+source/snapd/2.58+20.04.1
https://launchpad.net/ubuntu/+source/snapd/2.58+18.04.1