USN-5292-1: snapd vulnerabilities

Releases

• Ubuntu 21.10
• Ubuntu 20.04 LTS
• Ubuntu 18.04 ESM

Packages

• snapd - Daemon and tooling that enable snap packages

Details

James Troup discovered that snap did not properly manage the permissions for
the snap directories. A local attacker could possibly use this issue to expose
sensitive information. (CVE-2021-3155)

Ian Johnson discovered that snapd did not properly validate content interfaces
and layout paths. A local attacker could possibly use this issue to inject
arbitrary AppArmor policy rules, resulting in a bypass of intended access
restrictions. (CVE-2021-4120)

The Qualys Research Team discovered that snapd did not properly validate the
location of the snap-confine binary. A local attacker could possibly use this
issue to execute other arbitrary binaries and escalate privileges.
(CVE-2021-44730)

The Qualys Research Team discovered that a race condition existed in the snapd
snap-confine binary when preparing a private mount namespace for a snap. A
local attacker could possibly use this issue to escalate privileges and
execute arbitrary code. (CVE-2021-44731)

Update instructions

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

Ubuntu 21.10

• snap-confine - 2.54.3+21.10.1
• snapd - 2.54.3+21.10.1

Ubuntu 20.04

• snap-confine - 2.54.3+20.04
• snapd - 2.54.3+20.04

Ubuntu 18.04

• snap-confine - 2.54.3+18.04
• snapd - 2.54.3+18.04

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

References

• CVE-2021-44730
• CVE-2021-44731
• CVE-2021-4120
• CVE-2021-3155

Related notices

• USN-5292-2: snapd, snap-confine, ubuntu-core-snapd-units, golang-github-ubuntu-core-snappy-dev, snapd-xdg-open, ubuntu-core-launcher, golang-github-snapcore-snapd-dev, ubuntu-snappy, ubuntu-snappy-cli
• USN-5292-3: snapd, snap-confine, ubuntu-core-snapd-units, golang-github-ubuntu-core-snappy-dev, snapd-xdg-open, ubuntu-core-launcher, golang-github-snapcore-snapd-dev, ubuntu-snappy, ubuntu-snappy-cli