CVE-2020-13776

systemd: Mishandles numerical usernames beginning with decimal digits or 0x followed by hexadecimal digits

Severity Score

6.7

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

systemd through v245 mishandles numerical usernames such as ones composed of decimal digits or 0x followed by hex digits, as demonstrated by use of root privileges when privileges of the 0x0 user account were intended. NOTE: this issue exists because of an incomplete fix for CVE-2017-1000082.

systemd versiones hasta v245 maneja inapropiadamente los nombres de usuario numéricos, tales como los compuestos por dígitos decimales o 0x seguidos de dígitos hexadecimales, como es demostrado por el uso de privilegios root cuando era previsto privilegios de la cuenta de usuario 0x0. NOTA: este problema se presenta debido a una corrección incompleta para CVE-2017-1000082.

A flaw was found in systemd, where it mishandles numerical usernames beginning with decimal digits, or "0x" followed by hexadecimal digits. When the usernames are used by systemd, for example in service units, an unexpected user may be used instead. In some particular configurations, this flaw allows local attackers to elevate their privileges.

*Credits: N/A

Attack Vector

Local

Attack Complexity

High

Privileges Required

Low

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Local

Attack Complexity

High

Authentication

None

Confidentiality

Complete

Integrity

Complete

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-06-03 CVE Reserved
2020-06-03 CVE Published
2023-03-08 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-269: Improper Privilege Management
CWE-440: Expected Behavior Violation

CAPEC

References (5)

URL	Tag	Source
https://security.netapp.com/advisory/ntap-20200611-0003	Third Party Advisory

URL	Date	SRC

URL	Date	SRC
https://github.com/systemd/systemd/issues/15985	2023-11-07

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IYGLFEKG45EYBJ7TPQMLWROWPTZBEU63	2023-11-07
https://access.redhat.com/security/cve/CVE-2020-13776	2021-10-19
https://bugzilla.redhat.com/show_bug.cgi?id=1845534	2021-10-19

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Systemd Project Search vendor "Systemd Project"		Systemd Search vendor "Systemd Project" for product "Systemd"				<= 245 Search vendor "Systemd Project" for product "Systemd" and version " <= 245"		-		Affected
Netapp Search vendor "Netapp"		Active Iq Unified Manager Search vendor "Netapp" for product "Active Iq Unified Manager"				-		vmware_vsphere		Affected
Netapp Search vendor "Netapp"		Solidfire \& Hci Management Node Search vendor "Netapp" for product "Solidfire \& Hci Management Node"				-		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				32 Search vendor "Fedoraproject" for product "Fedora" and version "32"		-		Affected