CVE intelligence and bounded remediation

CVE-2018-8885 — Canonical Screen-Resolution-Extra security vulnerability

High CVSS 7

screenresolution-mechanism in screen-resolution-extra 0.17.2 does not properly use the PolicyKit D-Bus API, which allows local users to bypass intended access restrictions by leveraging a race condition via a setuid or pkexec process that is mishandled in a PolicyKitService._check_permission call.

Severity
High
CVSS
7 (3.0)
Published
2018-03-28
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-362

Affected products

  • canonical / screen-resolution-extra / 0.17.2
  • canonical / ubuntu_linux / 14.04
  • canonical / ubuntu_linux / 16.04
  • canonical / ubuntu_linux / 17.10

Matched remediation archetype

Race condition, TOCTOU, and lifecycle synchronization

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Check exposure

  • Map concurrent actors, shared state, lock boundaries, signals, callbacks, retries, and check-then-use sequences in the affected path.
  • Determine whether untrusted users can influence timing, object names, filesystem state, or repeated state transitions.
  • Identify clustered and multi-process behavior that repository-local tests may not represent.

Remediate safely

  • Make the sensitive state transition atomic or protect it with a consistently ordered synchronization primitive.
  • Perform authorization and invariant checks on the same authoritative object and transaction used for the operation.
  • Use unique private resources, safe ownership transfer, and idempotent operations; add deterministic concurrency regression tests.

Authoritative sources

Complete CVE record and remediation plan

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