CVE-2022-49892 is a high-severity vulnerability affecting the Linux kernel, specifically concerning the ftrace functionality. This vulnerability allows for a use-after-free condition which could be exploited if not addressed. The CVSS score for this vulnerability is 7.8, indicating significant risk potential due to its local attack vector, low complexity, and the requirement for low privileges to exploit. Risk to organizations includes unauthorized access to system resources, which could lead to further exploitation.
The urgency for defenders is high; organizations should prioritize patching immediately to prevent potential exploitation. As the vulnerability has been analyzed and patched, timely remediation is critical to mitigate associated risks.
The root cause of this vulnerability stems from improper management of dynamic ftrace operations, where unregistering one operation while another remains active can lead to a use-after-free scenario. This highlights the importance of rigorous synchronization in system-level code.
Given the nature of this vulnerability, organizations utilizing the affected versions of the Linux kernel may face significant operational risks. Immediate patching is essential to safeguard systems against potential threats.
Vulnerability Details
In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix use-after-free for dynamic ftrace_ops. KASAN reported a use-after-free with ftrace ops. It was found from vmcore that perf had registered two ops with the same content successively, both dynamic. After unregistering the second ops, a use-after-free occurred.
In ftrace_shutdown(), when the second ops is unregistered, the FTRACE_UPDATE_CALLS command is not set because there is another enabled ops with the same content. Also, both ops are dynamic and the ftrace callback function is ftrace_ops_list_func, so the FTRACE_UPDATE_TRACE_FUNC command will not be set. Eventually the value of 'command' will be 0 and ftrace_shutdown() will skip the rcu synchronization.
However, ftrace may be activated. When the ops is released, another CPU may be accessing the ops. Add the missing synchronization to fix this problem.
Technical Analysis
The root cause of CVE-2022-49892 is a use-after-free vulnerability due to inadequate synchronization when managing dynamic ftrace operations. Attackers may leverage this vulnerability through local attack vectors, exploiting the low complexity and low privileges required for execution.
The attack complexity is classified as low, as it does not require specialized knowledge or advanced skills to exploit. The exploitability score indicates that the vulnerability has a moderate likelihood of being successfully exploited when targeted, especially in systems where multiple ftrace operations are registered.
The confidentiality, integrity, and availability impacts are all rated as high due to the potential for unauthorized access to sensitive information and system resources, leading to significant operational disruptions.
Risk & Impact Analysis
Organizations running the affected Linux kernel versions face substantial risks, including potential unauthorized access and disruptions to critical services. Given the high CVSS score of 7.8, this vulnerability represents a serious threat to operational security.
The blast radius is considerable, as many systems rely on the Linux kernel across various environments, including servers and embedded devices. Organizations should assess their exposure and implement necessary patches to mitigate risk.
The urgency assessment based on the CVSS score necessitates immediate action. Organizations should address this vulnerability in their priority patch cycle to avoid exploitation.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerable versions of the Linux kernel include:
1. All versions from 4.1.45 to below 4.2.
2. All versions from 4.4.89 to below 4.5.
3. All versions from 4.9.52 to below 4.10.
4. All versions from 4.13.4 to below 5.10.154.
5. All versions from 5.11 to below 5.15.78.
6. All versions from 5.16 to below 6.0.8.
7. Versions 6.1:rc1, 6.1:rc2, 6.1:rc3 are also vulnerable.
Mitigation & Remediation
To mitigate this vulnerability, organizations should ensure they update to patched versions of the Linux kernel. The following patches are recommended:
1. Patch from https://git.kernel.org/stable/c/0e792b89e6800cd9cb4757a76a96f7ef3e8b6294.
2. Patch from https://git.kernel.org/stable/c/88561a66777e7a2fe06638c6dcb22a9fae0b6733.
3. Patch from https://git.kernel.org/stable/c/cc1b9961a0ceb70f6ca4e2f4b8bb71c87c7a495c.
4. Patch from https://git.kernel.org/stable/c/ea5f2fd4640ecbb9df969bf8bb27733ae2183169.
Detection Guidance
To detect potential exploitation attempts related to CVE-2022-49892, organizations should monitor for the following indicators:
1. Log entries related to ftrace operations that indicate abnormal behavior.
2. Behavioral anomalies in kernel performance, especially when managing dynamic ftrace operations.
3. Network signatures that align with unauthorized access attempts to kernel resources.
4. System changes that correlate with known exploitation patterns related to use-after-free vulnerabilities.
AppSecure Threat Intelligence Insight
CVE-2022-49892 represents a significant vulnerability within the Linux kernel, particularly due to its potential for exploitation in local environments. The patterns observed in this incident reflect a broader trend of use-after-free vulnerabilities that can lead to severe security implications.
Security teams should focus on enhancing their kernel management practices and ensuring that all relevant patches are applied promptly. The lessons from this vulnerability highlight the importance of thorough testing and validation of dynamic operations within kernel code.
Establishing a robust vulnerability management program is essential for proactive risk mitigation.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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