CVE-2021-3923 is a low-severity vulnerability found in the Linux kernel's implementation of RDMA over InfiniBand. This vulnerability allows an attacker with a privileged local account to leak kernel stack information by issuing commands to the /dev/infiniband/rdma_cm device node. Although this access is unlikely to leak sensitive user information, it can potentially be exploited to bypass existing kernel protection mechanisms. The CVSS score for this vulnerability is 2.3, indicating a low severity level.
Risk to organizations includes the potential for attackers to gain insights into kernel operations. This could lead to further vulnerabilities being exploited within the kernel environment. The urgency for defenders is moderate, as this vulnerability does not currently have any known exploits in the wild, but organizations should remain vigilant.
Organizations should prioritize monitoring for any unusual access patterns to the /dev/infiniband/rdma_cm device node and consider applying available patches to mitigate this risk.
The vulnerability was published on March 27, 2023, and has undergone modifications since its initial disclosure. Continuous monitoring and timely patching are essential to maintaining the security of systems affected by this vulnerability.
Vulnerability Details
The vulnerability allows an attacker with a privileged local account to leak kernel stack information. The affected systems include various versions of the Linux kernel, Red Hat Enterprise Linux, and Fedora, specifically versions prior to 5.15.14 for the Linux kernel and versions 6.0 through 8.0 for Red Hat. The CWE classification for this vulnerability is CWE-200, which corresponds to information exposure.
Technical Analysis
The root cause of the vulnerability lies in the kernel's implementation of RDMA over InfiniBand. Attackers may leverage local access to exploit this flaw with low complexity. The attack vector is local, requiring high privileges, and does not necessitate user interaction. Although the confidentiality impact is rated as low, there are no integrity or availability impacts associated with this vulnerability.
Risk & Impact Analysis
The deployment risk for this vulnerability is primarily associated with environments where privileged accounts are used. Given the low CVSS score, the urgency to address this vulnerability is moderate. Organizations should evaluate the potential blast radius of this vulnerability, especially in environments where sensitive data is processed or protected by the kernel.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The following versions are affected by this vulnerability: all versions of the Linux kernel prior to 5.15.14, and Red Hat Enterprise Linux versions 6.0 to 8.0, as well as Fedora version 37.
Mitigation & Remediation
Organizations should prioritize patching the affected systems. If a patch is not immediately available, consider implementing network controls to limit access to the vulnerable device. Regularly monitor logs for unusual access patterns to the /dev/infiniband/rdma_cm device node. For more comprehensive security practices, organizations may also benefit from penetration testing to identify and remediate similar vulnerabilities.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor logs for any commands issued to the /dev/infiniband/rdma_cm device node. Look for abnormal patterns or repeated access attempts that may indicate an attempt to exploit the vulnerability.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-3923 lies in the potential for similar vulnerabilities to be discovered in other kernel implementations. Security teams should conduct regular assessments and keep abreast of emerging trends in kernel security to preemptively address potential threats. For further reading on securing Linux environments, organizations may find value in our comprehensive guides on Linux security best practices and continuous security testing strategies.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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