CVE-2019-3843
Description
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.
Statement
This issue did not affect the versions of systemd as shipped with Red Hat Enterprise Linux 7 as they did not include support for DynamicUser property.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.5 | 7.8 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | High | N/A |
| Integrity Impact | Low | High | N/A |
| Availability Impact | Low | High | N/A |
Vector
Red Hat: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Access Control
Technical Impact: Gain Privileges or Assume Identity
A user can access restricted functionality and/or sensitive information that may include administrative functionality and user accounts.
Acknowledgements
Red Hat would like to thank Jann Horn (Google Project Zero) for reporting this issue.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
