CVE-2021-33910 is a medium-severity vulnerability in Systemd, specifically in the basic/unit-name.c file, that has been identified in versions prior to 246.15, 247.8, 248.5, and 249.1. This vulnerability allows memory allocation with an excessive size value, which can lead to an operating system crash. The attack vector is local, meaning an attacker must have local access to the system to exploit this vulnerability.
The CVSS score for this vulnerability is 5.5, indicating a medium severity level. The implications of this vulnerability are significant, as it can compromise the availability of the system, potentially leading to downtime and disruption of services. Organizations relying on affected versions of Systemd should prioritize patching to mitigate potential risks.
As of now, there are no known exploits or public proof-of-concept codes available for this vulnerability. However, given the nature of the vulnerability and its capacity to cause system crashes, organizations should remain vigilant and apply patches as part of their regular security maintenance.
Organizations should address this vulnerability in their priority patch cycle to ensure continued operational integrity and security.
Vulnerability Details
The vulnerability is described as follows: basic/unit-name.c in Systemd prior to versions 246.15, 247.8, 248.5, and 249.1 has a memory allocation with an excessive size value, involving strdupa and alloca for a pathname controlled by a local attacker, resulting in an operating system crash.
The CVSS score is 5.5 (Medium) indicating that the attack vector is local, with low attack complexity and low privileges required, while user interaction is not needed. The impact on availability is high, while confidentiality and integrity are not affected.
Technical Analysis
The root cause of this vulnerability lies in the improper handling of memory allocation within the Systemd code. An attacker with local access can exploit this flaw by providing a specially crafted pathname, leading to excessive memory allocation and consequently crashing the operating system.
The attack vector for this vulnerability is local, thus requiring the attacker to have physical or logical access to the system. The complexity of this attack is low, as it does not require sophisticated techniques. Low privileges are sufficient for the attack to succeed, with no user interaction required.
In terms of impact, the vulnerability primarily affects the availability of the system, resulting in potential downtime. The confidentiality and integrity of the system are not directly compromised.
Risk & Impact Analysis
The real-world risk associated with CVE-2021-33910 is significant, particularly for organizations running affected versions of Systemd. The potential for an attacker to crash the operating system poses serious operational risks, including service disruption and potential loss of productivity.
Organizations should assess their exposure to this vulnerability, particularly if they operate critical systems running affected versions. The blast radius potential is considerable, as a successful exploitation could bring down essential services.
Given the medium severity rating and the presence of this vulnerability in widely used systems, organizations should prioritize patching immediately.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability affects the following versions of Systemd: all versions prior to 246.15, 247.8, 248.5, and 249.1. It also impacts Fedora versions 33 and 34, Debian Linux version 10.0, and products from NetApp, including HCI Management Node and SolidFire.
Mitigation & Remediation
Organizations should prioritize updating to the latest versions of Systemd to mitigate this vulnerability. The following versions are available for upgrade: 246.15 or later, 247.8 or later, 248.5 or later, and 249.1 or later. If an immediate patch cannot be applied, consider implementing configuration hardening and network controls to limit access to the affected systems.
For ongoing monitoring, organizations should implement logging to detect behavioral anomalies that may indicate exploitation attempts. Regular penetration testing can also help identify vulnerabilities and ensure security measures are effective. Organizations can validate remediation through continuous security testing to identify similar weaknesses.
Detection Guidance
Organizations should monitor logs for indicators of exploitation attempts. Specifically, look for abnormal memory allocation patterns or unexpected crashes in Systemd services. Behavioral anomalies may signal attempts to exploit this vulnerability. Additionally, network signatures that indicate local access attempts should be tracked.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-33910 lies in its illustration of how memory management issues can lead to critical system vulnerabilities. This vulnerability serves as a reminder for security teams to conduct thorough code reviews and implement best practices in memory handling.
It also highlights the importance of keeping software dependencies up to date, as vulnerabilities in foundational components can have widespread implications. Organizations are encouraged to adopt a proactive stance towards vulnerability management and to continuously assess their security posture.
Security teams should use this vulnerability as a case study for training and awareness, ensuring that developers understand the risks associated with improper memory allocation. For more information, organizations can refer to our penetration testing methodology guide to enhance their security practices.
Finally, organizations are urged to consider the implementation of rigorous security testing protocols, including regular assessments and vulnerability scanning, to identify and remediate weaknesses proactively.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
.webp)