In the Linux kernel, a medium-severity vulnerability (CVE-2024-56644) has been identified, which affects several versions of the Linux kernel. This vulnerability allows for the leaking of destination (dst) objects in the function ip6_negative_advice() when executed for an expired IPv6 route located in the exception table. This leak can occur under specific conditions related to ICMPv6 packets and TCP connection timeouts.
The CVSS score assigned to this vulnerability is 5.5, indicating a medium severity level. The implications of this vulnerability are significant, as an unbalanced reference count can lead to resource leaks, particularly affecting the loopback device of a net namespace that is being destroyed. Organizations running affected versions of the Linux kernel should take this vulnerability seriously and prioritize remediation.
Currently, there is no public exploit confirmed for this vulnerability, and it is not listed in the Known Exploited Vulnerabilities (KEV) catalog. However, organizations are urged to monitor and apply relevant patches as they become available to mitigate potential risks.
Organizations should prioritize patching immediately to prevent any potential negative impact from this vulnerability.
Vulnerability Details
The vulnerability in question is primarily found within the Linux kernel, specifically in the handling of expired exception dst cached in sockets. The following conditions must be met for the leak to occur:
* An ICMPv6 packet indicating a change of the MTU for the path is received, resulting in an exception dst being created.* A TCP connection that uses the exception dst for routing packets must start timing out, which triggers TCP retransmissions.* After the exception dst expires, the FIB6 garbage collector must not run before TCP executes ip6_negative_advice() for the expired exception dst.
The root cause of the vulnerability stems from the fact that when TCP executes ip6_negative_advice() for an expired exception dst, if no other socket holds a reference to the dst, it results in an unbalanced reference count. This condition can lead to a memory leak, ultimately affecting system performance.
Technical Analysis
The attack vector for this vulnerability is local, as it requires access to the system where the Linux kernel is running. The complexity of the attack is low, meaning that an attacker with sufficient privileges can exploit this vulnerability without requiring significant effort. Privileges required for exploitation are low, and user interaction is not needed.
The impacts of this vulnerability include a high availability impact, as the leaking of resources can lead to degraded system performance or even crashes under certain conditions. There is no confidentiality or integrity impact associated with this vulnerability.
Risk & Impact Analysis
The real-world deployment risk of this vulnerability is moderate. Organizations running affected versions of the Linux kernel should assess their exposure and the potential for exploitation. The urgency for remediation is highlighted by the CVSS score of 5.5, which indicates that while the vulnerability is not critical, it still poses a significant risk.
The potential blast radius is primarily limited to systems using specific kernel versions that are affected by this vulnerability. Organizations should evaluate their network infrastructure and consider the implications of this vulnerability on their operational capabilities.
Organizations should address this vulnerability in their priority patch cycle, ensuring that they are running the latest, secure versions of the Linux kernel.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of the Linux kernel include:
• All versions prior to vendor patch for Debian Linux.
Mitigation & Remediation
To mitigate this vulnerability, it is crucial for organizations to apply patches provided by the Linux kernel maintainers. The specific patches addressing this vulnerability are available through the official repositories. Organizations should monitor and ensure that their systems are running updated versions of the Linux kernel.
In addition to patching, organizations should consider implementing configuration hardening practices and performing thorough security assessments. For deeper insights into effective security measures, organizations can refer to resources on application security assessments and continuous penetration testing to maintain robust security posture.
Detection Guidance
Organizations should implement monitoring solutions that can identify log indicators associated with this vulnerability. Key indicators to monitor include:
• Unusual network activity related to TCP connections.
• Behavior anomalies in network namespace management.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2024-56644 reflects ongoing challenges with resource management in kernel networking code. Security teams should recognize patterns that emerge from such vulnerabilities, especially those impacting availability.
Continued vigilance and proactive security measures are essential for protecting systems against evolving threats.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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