Vulnerability Name:

CVE-2020-27837 (CCN-194009)

Assigned:2020-12-21
Published:2020-12-21
Updated:2020-12-30
Summary:A flaw was found in GDM in versions prior to 3.38.2.1. A race condition in the handling of session shutdown makes it possible to bypass the lock screen for a user that has autologin enabled, accessing their session without authentication. This is similar to CVE-2017-12164, but requires more difficult conditions to exploit.
CVSS v3 Severity:6.4 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)
5.6 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Physical
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): High
5.3 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)
4.6 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): Low
Availibility (A): None
CVSS v2 Severity:4.4 Medium (CVSS v2 Vector: AV:L/AC:M/Au:N/C:P/I:P/A:P)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Medium
Authentication (Au): None
Impact Metrics:Confidentiality (C): Partial
Integrity (I): Partial
Availibility (A): Partial
5.0 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): Partial
Availibility (A): None
Vulnerability Type:CWE-362
Vulnerability Consequences:Bypass Security
References:Source: MITRE
Type: CNA
CVE-2020-27837

Source: CCN
Type: Red Hat Bugzilla – Bug 1906812
(CVE-2020-27837) - CVE-2020-27837 gdm: lock screen bypass when autologin is set

Source: MISC
Type: Issue Tracking, Patch, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1906812

Source: XF
Type: UNKNOWN
gdm-cve202027837-sec-bypass(194009)

Source: CCN
Type: gdm GIT Repository
session-worker: Don't switch back VTs until session is fully exited

Source: CCN
Type: WhiteSource Vulnerability Database
CVE-2020-27837

Vulnerable Configuration:Configuration 1:
  • cpe:/a:gnome:gnome_display_manager:*:*:*:*:*:*:*:* (Version < 3.38.2.1)

    • * Denotes that component is vulnerable
    Oval Definitions
    Definition IDClassTitleLast Modified
    oval:org.opensuse.security:def:7892
    P
    		gdm-41.3-150400.4.6.1 on GA media (Moderate)
    2023-06-12
    oval:org.opensuse.security:def:3274
    P
    		libusbmuxd4-1.0.10-2.3 on GA media (Moderate)
    2022-06-28
    oval:org.opensuse.security:def:94904
    P
    		gdm-41.3-150400.2.7 on GA media (Moderate)
    2022-06-22
    oval:org.opensuse.security:def:112282
    P
    		gdm-41.0-1.1 on GA media (Moderate)
    2022-01-17
    oval:org.opensuse.security:def:105807
    P
    		gdm-41.0-1.1 on GA media (Moderate)
    2021-10-01
    BACK
    gnome gnome display manager *