In the Linux kernel, a medium-severity vulnerability has been identified related to the netfilter component, specifically in nft_set_rbtree. This vulnerability allows for an overlap expiration walk, leading to failures in removing timed-out entries. The lazy garbage collection mechanism fails to release the remaining half of the interval, which can lead to potential denial of service.
The impact of this vulnerability is classified as high on availability, with a CVSS score of 5.5. This indicates that a local attacker with low privileges may exploit this vulnerability with low complexity and no user interaction required. Organizations operating affected Linux kernel versions are at risk if timely action is not taken.
Given the potential impact, organizations should prioritize patching immediately. The vulnerability is present in various versions of the Linux kernel, and failure to apply the necessary updates could result in service disruptions.
The vulnerability details can be reproduced using specific test cases in the nftables.git repository, which further emphasizes the importance of addressing this issue promptly.
Vulnerability Details
The specific vulnerability description states: 'In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_set_rbtree: fix overlap expiration walk. The lazy gc on insert that should remove timed-out entries fails to release the other half of the interval, if any.' Additionally, the use of rbe_prev vs. prev pointer introduces further issues if not handled correctly.
The CVSS score of 5.5 categorizes this vulnerability as medium severity, with an attack vector classified as local. The attack complexity is low, which means that an attacker does not need significant resources to exploit this vulnerability. The privileges required are also low, meaning that a standard user could potentially exploit the vulnerability.
Organizations should note that the vulnerability is listed under CWE-476, which pertains to NULL Pointer Dereference vulnerabilities. Given the vulnerability's nature, it is essential to ensure that proper checks are in place to mitigate this risk.
Technical Analysis
The root cause of this vulnerability lies in the improper handling of memory management within the Linux kernel's netfilter component. Specifically, the garbage collection mechanism fails to free memory associated with timed-out entries correctly, leading to potential denial of service conditions.
The attack vector is classified as local, indicating that an attacker must have local access to the system to exploit this vulnerability. The attack complexity is low, meaning attackers can exploit it with minimal effort. In this case, no user interaction is required to trigger the vulnerability.
The availability impact is high, as successful exploitation can lead to service outages. However, there is no confidentiality or integrity impact associated with this vulnerability, making it focused solely on availability.
Risk & Impact Analysis
Risk to organizations includes potential denial of service, which can disrupt services and impact operational continuity. The availability impact is particularly concerning as it can lead to significant downtime and affect user trust.
Organizations should assess their exposure based on the versions of the Linux kernel they are running. The vulnerability affects multiple versions, and the lack of public exploits indicates a somewhat lower immediate threat, but this should not lead to complacency.
Urgency for defenders must be high, given the potential for service disruption. Organizations should address this vulnerability in their priority patch cycle to safeguard against possible exploitation.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The following versions of the Linux kernel are affected by this vulnerability:
• All versions from 5.10.166 to 5.10.190 (exclusive) • All versions from 5.15.91 to 5.15.124 (exclusive) • All versions from 6.1.9 to 6.1.43 (exclusive) • All versions from 6.2.1 to 6.4.8 (exclusive) • Specific releases 6.2: rc6, rc7, rc8 and 6.5: rc1, rc2, rc3.
Mitigation & Remediation
Organizations should apply patches as soon as they become available. Continuous monitoring and regular updates to the Linux kernel can significantly reduce exposure to this vulnerability.
If patches are not available, organizations should implement workarounds to mitigate risks. It is recommended to restrict access to the kernel and monitor for any unusual activities that may indicate exploitation attempts.
For more information on effective security measures, organizations can refer to the following resources for guidance on penetration testing and best practices.
Detection Guidance
Organizations should monitor logs for any indicators of unauthorized access or anomalies that may suggest attempts to exploit this vulnerability. Behavioral anomalies, such as unexpected kernel behavior or crashes, should be investigated promptly.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability highlights the importance of robust memory management in software development. It serves as a reminder for security teams to ensure thorough testing and validation processes are in place.
This vulnerability represents a pattern of memory management flaws that can lead to severe consequences if left unaddressed. Security teams should invest in proactive measures to identify and remediate similar vulnerabilities.
As a strategic defensive takeaway, organizations should strengthen their security posture by ensuring all components of their systems are maintained and updated regularly. For further insights on vulnerability management, consider exploring our vulnerability management program and best practices.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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