In the Linux kernel, a high-severity vulnerability has been identified, specifically a use-after-free issue within the GPIO chip device file management. This vulnerability allows for a race condition that could lead to unintended GPIO line events being generated for userspace applications when they should not be. This could potentially allow attackers to exploit this flaw, although it is important to note that user-space applications would not have the opportunity to read those events if the chrdev is closed.
The vulnerability has been classified with a CVSS score of 7, indicating high severity. The impact includes high confidentiality, integrity, and availability risks, making it critical for organizations that utilize the Linux kernel in their operations to address this vulnerability promptly. The vulnerability was officially published on May 30, 2024, and has been categorized under CWE-362 and CWE-416.
Organizations should prioritize patching immediately to mitigate risks associated with this vulnerability. Currently, there are no known public exploits or proof-of-concept code available, suggesting that while the vulnerability is severe, it may not yet be actively exploited in the wild.
Defenders are advised to monitor their systems and apply necessary updates to avoid potential exploitation. The urgency for remediation is high, given the potential impact this vulnerability could have on system integrity and availability.
Vulnerability Details
The vulnerability is located in the GPIO library of the Linux kernel, specifically in the management of device files. The issue arises due to a use-after-free condition where the 'watched_lines' bitmap is freed before the unregistration of the notifier chain. This results in a race condition that could allow unintended event notifications to be generated for user space.
The CVSS score of 7 indicates a high severity level, reflecting the significant impact this vulnerability could have on affected systems. It is critical that organizations identify all instances of the Linux kernel that may be running vulnerable versions and take appropriate actions to update them.
The vulnerability affects Linux kernel versions from 5.7 to 6.6.31 and also includes specific release candidates for version 6.9. Organizations should ensure they are not running any of these vulnerable versions.
Technical Analysis
The root cause of this vulnerability stems from improper synchronization during the device file closure process in the Linux kernel. When the GPIO chip device file is closed, the GPIO lines associated with it are being freed while the notifier chain unregistration is still pending, leading to a use-after-free condition. This allows for race conditions where an event notification can be triggered after the associated resources have already been released.
The attack vector is local, meaning that an attacker would need local access to the system to exploit this vulnerability. The attack complexity is classified as high, requiring specific conditions to be met for the exploit to be successful.
Given that the privileges required to exploit this vulnerability are low, and no user interaction is needed, it poses a significant risk to systems where local access can be obtained. The impacts on confidentiality, integrity, and availability are all rated high, making it critical for organizations to implement necessary controls and updates.
Risk & Impact Analysis
The risk to organizations includes potential unauthorized access to GPIO line events, which can lead to unintended behaviors in applications relying on these events. The blast radius for this vulnerability can be significant, especially in critical infrastructure that depends on GPIO for hardware interaction.
Organizations should assess the potential impact of this vulnerability on their specific environments. With the CVSS score indicating high severity, the urgency to address this vulnerability is paramount as attackers may leverage it to disrupt operations or gain unauthorized access.
The EPSS score indicates a low likelihood of exploitation at this time; however, the status can change, and vigilance is necessary. Continuous monitoring for vulnerabilities and patch management should be integral parts of security operations.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability affects all versions of the Linux kernel from 5.7 to 6.6.31, as well as specific release candidates for version 6.9 (rc1 through rc7). Organizations should ensure they update to the latest version of the kernel that addresses this vulnerability.
Mitigation & Remediation
To mitigate this vulnerability, organizations are advised to apply the latest patches provided by the Linux kernel maintainers. It is crucial to ensure that the bitmap_free() function is called after unregistering the notifier chain to prevent the use-after-free condition.
In the absence of a patch, organizations should consider implementing workarounds that limit access to the GPIO lines while the device files are being managed. Proper configuration hardening and monitoring for unusual activity involving GPIO lines should also be implemented to detect any potential exploitation attempts.
For comprehensive remediation, organizations should consider utilizing penetration testing to assess their environment for similar vulnerabilities.
Detection Guidance
Organizations should monitor logs for indicators associated with GPIO line state changes. Additionally, any unauthorized access attempts or anomalies in GPIO line usage should be flagged for further investigation. Behavioral anomalies that deviate from normal patterns should also be closely monitored.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2024-36899 lies in the potential for similar vulnerabilities to be introduced in the future through improper management of shared resources in multi-threaded environments. This incident highlights the importance of robust development practices, including proper synchronization and resource management, to prevent vulnerabilities from arising.
Organizations should learn from this vulnerability to enhance their security posture. Regular security assessments, including penetration testing methodology, should be integrated into development lifecycles.
Additionally, organizations should consider adopting proactive security measures, such as regular code reviews and threat modeling, to identify potential weaknesses early in the development process. Continuous training for developers on secure coding practices is also essential to mitigate risks associated with vulnerabilities.
For further insights, organizations may benefit from exploring vulnerability management program design and implementing a comprehensive approach to vulnerability remediation.
By staying informed and proactive, organizations can significantly reduce their risk of falling victim to similar vulnerabilities in the future.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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