CVE-2017-20002

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-03-17 · updated 2026-06-17
Weakness: CWE-269

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.

Affected products

Debian Linux: 9.0
Debian Shadow: 4.4

References

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=877374
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914957
https://lists.debian.org/debian-lts-announce/2021/03/msg00020.html
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=877374
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914957
https://lists.debian.org/debian-lts-announce/2021/03/msg00020.html

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