SB2022021816 - Ubuntu update for snapd

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Main Vulnerability Database SB2022021816

SB2022021816 - Ubuntu update for snapd

Published: February 18, 2022 Updated: July 10, 2023

Security Bulletin ID SB2022021816
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 4
Exploitation vector Local access
Highest impact Code execution

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 4 vulnerabilities.


1) Incorrect default permissions (CVE-ID: CVE-2021-3155)

CWE-ID: CWE-276 - Incorrect Default Permissions

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists due to snapd creates "~/snap" directories in user home directories without specifying owner-only permissions. A local user can gain access to potentially sensitive information.


2) Input validation error (CVE-ID: CVE-2021-4120)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to insufficient validation of snap content interface and layout paths. A local user can inject arbitrary AppArmor policy rules via malformed content interface and layout declarations and execute arbitrary code with elevated privileges.


3) UNIX hardlink following (CVE-ID: CVE-2021-44730)

CWE-ID: CWE-62 - UNIX Hard Link

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a hardlink following issue within the the snap-confine binary. A local user can create a hardlink to system binaries and execute them with elevated privileges.


4) Race condition (CVE-ID: CVE-2021-44731)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear


The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition in the snap-confine binary when preparing a private mount namespace for a snap.. A local user can  bind-mount their own contents inside the snap's private mount namespace and execute arbitrary code with root privileges.


Remediation

Install update from vendor's website.

References