In the Linux kernel, a vulnerability has been identified and resolved regarding the implementation of MPTCP (MultiPath TCP). The issue arises in the function subflow_finish_connect(), which utilizes four fields (backup, join_id, thmac, none) that may contain garbage unless the option OPTION_MPTCP_MPJ_SYNACK is set in the mptcp_parse_option(). This flaw is particularly significant as it can lead to unintended behavior in network communications.
The vulnerability has been classified with a CVSS score of 5.5, indicating a medium severity level. The attack vector is classified as local, meaning an attacker would need local access to exploit the vulnerability. The potential impacts include a high availability risk, which could disrupt normal operations of systems utilizing the affected kernel versions.
Organizations should prioritize patching immediately. The vulnerability affects several versions of the Linux kernel, and without remediation, systems remain at risk of performance issues. The urgency for defenders cannot be overstated, as the effects of this vulnerability can compromise system availability.
Given the nature of the vulnerability, it is crucial for system administrators to evaluate their current kernel versions against the identified vulnerable ranges and take appropriate action to ensure that systems are secured against potential exploitation.
Vulnerability Details
The vulnerability in question has been documented in CVE-2024-35840. The specific details state that the Linux kernel's handling of MPTCP subflows may lead to unexpected behavior if certain options are not correctly implemented. As a result, this can lead to high availability impacts, with the potential to disrupt normal operations.
The vulnerability was published on May 17, 2024, and marked analyzed, receiving a CVSS score of 5.5, which signifies a medium severity. This classification is due to the local attack vector and the low complexity required for exploitation, coupled with a low privilege requirement. The lack of user interaction further amplifies the risk.
Currently, no CWE classification is available for this vulnerability. The affected product is the Linux kernel, particularly versions starting from 5.7 up to but not including versions 5.15.148, 6.1.75, 6.6.14, and 6.7.2.
Technical Analysis
The root cause of this vulnerability stems from improper handling of subflow connections in the MPTCP implementation within the Linux kernel. Specifically, the fields utilized in the subflow_finish_connect() function can retain garbage values unless the OPTION_MPTCP_MPJ_SYNACK is explicitly set. This oversight can result in unpredictable network behavior, leading to potential service interruptions.
The attack vector is local, requiring an attacker to have local access to the system, which could be achieved through physical access or other local means. The complexity of the attack is low, and the privileges required are also low, meaning that even a non-privileged user could potentially exploit this flaw.
No user interaction is required to exploit this vulnerability, which increases the likelihood of it being exploited in a local environment. While there is no confidentiality or integrity impact, the availability impact is classified as high, indicating that affected systems could experience significant downtime or degraded performance.
Risk & Impact Analysis
The deployment of this vulnerability presents real-world risks for organizations utilizing the affected versions of the Linux kernel. Given its medium severity, organizations must assess their exposure to this vulnerability, particularly in environments where high availability is critical.
The potential blast radius of this vulnerability is significant, especially in local network environments where multiple systems may rely on the same kernel version. The cascading effects of a denial-of-service scenario could lead to widespread operational disruptions.
Organizations must act swiftly to patch vulnerable systems as part of their priority patch cycle. The risk to organizations includes degraded system performance and potential service interruptions due to the high availability impact.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of the Linux kernel include:
Versions from 5.7 to below 5.15.148, from 5.16 to below 6.1.75, from 6.2 to below 6.6.14, and from 6.7 to below 6.7.2 are all vulnerable. Organizations should ensure they are running patched versions to avoid exposure.
Mitigation & Remediation
Organizations must apply patches as soon as they are available to mitigate this vulnerability. The following patches are recommended for immediate application:
Penetration testing can also help identify if systems are still vulnerable post-patching.
In addition to patching, organizations should consider implementing network controls and monitoring to detect any unusual activity that may indicate attempted exploitation of this vulnerability.
Detection Guidance
To detect potential exploitation attempts, organizations should monitor for the following indicators:
Log indicators may include unusual subflow connection attempts, system performance anomalies, and any unauthorized access attempts that could be related to the exploitation of this vulnerability.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2024-35840 reflects ongoing challenges in maintaining robust kernel security, particularly with evolving network protocols like MPTCP. This vulnerability underscores the importance of rigorous testing and validation practices in the development lifecycle.
Security teams should take this incident as a lesson to implement comprehensive security assessments, including regular penetration testing and adherence to secure coding practices.
Organizations looking to enhance their security posture can explore various resources, such as the penetration testing methodology and vulnerability management program design to proactively address such risks.
As organizations continue to adapt to the changing threat landscape, understanding vulnerabilities like CVE-2024-35840 will be pivotal in safeguarding critical infrastructure.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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