--- title: "CVE-2017-20002\n | Ubuntu" description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/CVE-2017-20002?format=md keywords: index, follow --- # CVE-2017-20002 Publication date 17 March 2021 Last updated 25 August 2025 --- Ubuntu priority **Medium** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **7.8 · High** [Score breakdown](https://ubuntu.com/security/CVE-2017-20002?format=md#impact-score) Toggle side navigation ## 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](https://ubuntu.com/security/CVE-2017-20002?format=md#notes) ## 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 | --- * [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) * [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses) ## Notes --- ### [mdeslaur](https://launchpad.net/~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 ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-20002) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2017-20002) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2017-20002) * [Debian](https://security-tracker.debian.org/tracker/CVE-2017-20002) ### Other references * * * *