CVE intelligence and bounded remediation

CVE-2020-5202 — apt-cacher-ng through 3.3 allows local users to obtain sensitive information by hijacking the hardcoded TCP port

Medium CVSS 5.5

apt-cacher-ng through 3.3 allows local users to obtain sensitive information by hijacking the hardcoded TCP port. The /usr/lib/apt-cacher-ng/acngtool program attempts to connect to apt-cacher-ng via TCP on localhost port 3142, even if the explicit SocketPath=/var/run/apt-cacher-ng/socket command-line option is passed. The cron job /etc/cron.daily/apt-cacher-ng (which is active by default) attempts this periodically. Because 3142 is an unprivileged port, any local user can try to bind to this port and will receive requests from acngtool. There can be sensitive data in these requests, e.g., if AdminAuth is enabled in /etc/apt-cacher-ng/security.conf. This sensitive data can leak to unprivileged local users that manage to bind to this port before the apt-cacher-ng daemon can.

Severity
Medium
CVSS
5.5 (3.1)
Published
2020-01-21
CISA KEV
Not currently listed
Ecosystem
software/application

Affected products

  • apt-cacher-ng_project / apt-cacher-ng
  • debian / debian_linux / 8.0
  • debian / debian_linux / 9.0
  • debian / debian_linux / 10.0
  • opensuse / backports / sle-15
  • opensuse / leap / 15.1

Matched remediation archetype

Information disclosure and sensitive data exposure

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace sensitive data through responses, errors, logs, metrics, traces, caches, exports, files, backups, and client bundles.
  • Identify affected subjects, tenants, retention windows, access controls, and downstream copies without opening unnecessary sensitive records.
  • Review metadata, timing, status, length, and existence signals as well as direct content disclosure.

Remediate safely

  • Minimize collection and output, apply field-level authorization and redaction at a centralized boundary, and return generic external errors.
  • Remove secrets and sensitive data from logs, artifacts, URLs, caches, and client-side bundles; rotate credentials that may have been exposed.
  • Update the affected component and add synthetic-data tests for response, error, observability, and export paths.

Authoritative sources

Complete CVE record and remediation plan

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