CVE intelligence and bounded remediation

CVE-2017-20002 — The Debian shadow package before 1:4.5-1 for Shadow incorrectly lists pts/0 and pts/1 as physical terminals in /etc/securetty

High CVSS 7.8

The Debian shadow package before 1:4.5-1 for Shadow incorrectly lists pts/0 and pts/1 as physical terminals in /etc/securetty. This allows local users to login as password-less users even if they are connected by non-physical means such as SSH (hence bypassing PAM's nullok_secure configuration). This notably affects environments such as virtual machines automatically generated with a default blank root password, allowing all local users to escalate privileges.

Severity
High
CVSS
7.8 (3.1)
Published
2021-03-17
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-269

Affected products

  • debian / shadow / 4.4
  • debian / debian_linux / 9.0

Matched remediation archetype

Privilege escalation and unsafe privilege management

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

Check exposure

  • Map service accounts, operating-system identities, roles, capabilities, impersonation, set-user transitions, and administrative helper paths.
  • Determine whether untrusted users or lower-privilege processes can reach the affected transition or modify inputs it trusts.
  • Review file, socket, registry, device, job, container, and cloud-role permissions used before and after privilege changes.

Remediate safely

  • Apply the supported fix and redesign privileged operations as a minimal, authenticated, allowlisted interface.
  • Drop privileges before processing untrusted input, verify the drop succeeds, and remove unnecessary roles, capabilities, and write permissions.
  • Validate ownership and permissions at time of use and add explicit lower-to-higher privilege boundary tests.

Authoritative sources

Complete CVE record and remediation plan

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