systemd DynamicUser Property access control

HistoryDiffrelatejsonxmlCTI

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.7	$0-$5k	0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in systemd. This issue affects some unknown processing of the component DynamicUser Property Handler. This manipulation causes access control. The identification of this vulnerability is CVE-2019-3843. The attack can only be executed locally. Furthermore, there is an exploit available.

Detailsinfo

A vulnerability has been found in systemd (affected version unknown) and classified as critical. Affected by this vulnerability is an unknown functionality of the component DynamicUser Property Handler. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-264. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

It was discovered that a systemd service that uses DynamicUser property can create a SUID/SGID binary that would be allowed to run as the transient service UID/GID even after the service is terminated. A local attacker may use this flaw to access resources that will be owned by a potentially different service in the future, when the UID/GID will be recycled.

The bug was discovered 02/05/2019. The weakness was shared 04/26/2019 as not defined bug report (Bugzilla). The advisory is shared at bugzilla.redhat.com. This vulnerability is known as CVE-2019-3843 since 01/03/2019. An attack has to be approached locally. The successful exploitation needs a single authentication. Technical details are unknown but a public exploit is available. MITRE ATT&CK project uses the attack technique T1068 for this issue.

A public exploit has been developed in ANSI C and been published immediately after the advisory. It is possible to download the exploit at exploit-db.com. It is declared as proof-of-concept. The vulnerability was handled as a non-public zero-day exploit for at least 80 days. During that time the estimated underground price was around $0-$5k.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at Exploit-DB (46760). The entry VDB-134150 is related to this item. If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

systemd

License

open-source

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.7

VulDB Base Score: 5.3
VulDB Temp Score: 4.8
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

CNA Base Score: 4.5
CNA Vector (Red Hat, Inc.): 🔍

CVSSv2info

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-264
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Programming Language: 🔍
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Exploit-DB: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍
Exploit Delay Time: 🔍

Timelineinfo

01/03/2019 🔍
02/05/2019 +33 days 🔍
04/26/2019 +80 days 🔍
04/26/2019 +0 days 🔍
04/26/2019 +0 days 🔍
04/27/2019 +1 days 🔍
12/23/2024 +2067 days 🔍

Sourcesinfo

Advisory: USN-4269-1
Status: Not defined
Confirmation: 🔍

CVE: CVE-2019-3843 (🔍)
GCVE (CVE): GCVE-0-2019-3843
GCVE (VulDB): GCVE-100-134149
SecurityFocus: 108116

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 04/27/2019 08:45
Updated: 12/23/2024 10:36
Changes: 04/27/2019 08:45 (63), 06/07/2020 08:11 (2), 09/07/2023 16:03 (5), 09/07/2023 16:10 (12), 12/23/2024 10:36 (18)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.