CVE-2017-20002

Publication date 17 March 2021

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
shadow	20.10 groovy	Not affected
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected

Notes

mdeslaur

introduced in 1:4.4-2 and removed in 4.5-1

Severity score breakdown

CVSS version: CVSS v3.0

Base score 7.8 · High

Base metrics

Parameter	Value
Attack vector	Local
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	High
Availability impact	High

Scores

Parameter	Value
Base score	7.8 · High
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H