Ubuntu Security Notice 5292-3 - USN-5292-1 fixed several vulnerabilities in snapd. This update provides the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM. 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. 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. 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. 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.
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Ubuntu Security Notice USN-5292-3
February 18, 2022
snapd vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM
Summary:
Several security issues were fixed in snapd.
Software Description:
- snapd: Daemon and tooling that enable snap packages
Details:
USN-5292-1 fixed several vulnerabilities in snapd. This update provides the
corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.
Original advisory 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 16.04 ESM:
snap-confine 2.54.3+16.04~esm2
snapd 2.54.3+16.04~esm2
Ubuntu 14.04 ESM:
snap-confine 2.54.3+14.04~esm1
snapd 2.54.3+14.04~esm1
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-5292-3
https://ubuntu.com/security/notices/USN-5292-1
CVE-2021-3155, CVE-2021-4120, CVE-2021-44730, CVE-2021-44731