CVE-2021-38300 is a high-severity vulnerability affecting the Linux kernel prior to version 5.4.10. This vulnerability allows execution of arbitrary code within the kernel context due to the generation of undesirable machine code when transforming unprivileged cBPF programs. The issue arises from the fact that conditional branches can exceed the 128 KB limit of the MIPS architecture, leading to potential exploitation.
The CVSS base score for this vulnerability is 7.8, indicating a high severity level. The attack vector is local, which means that an attacker must have access to the vulnerable system. The attack complexity is low, and only low privileges are required to exploit the vulnerability. This combination of factors highlights the real-world risk posed by this vulnerability to organizations.
Organizations should prioritize patching immediately to address this vulnerability and protect against potential exploits. The implications of a successful attack could lead to significant impacts on confidentiality, integrity, and availability.
Currently, there are no known public exploits or proof of concept available for CVE-2021-38300. However, the potential for exploitation exists, and organizations must remain vigilant.
Vulnerability Details
This vulnerability allows execution of arbitrary code within the kernel context due to improper handling of conditional branches in the MIPS architecture. The affected product is the Linux kernel, with a CVSS score of 7.8, indicating a high severity level. The vulnerability was published on September 20, 2021, and has been classified as modified.
Technical Analysis
The root cause of CVE-2021-38300 lies in the kernel's handling of the cBPF JIT compiler for MIPS. When transforming unprivileged cBPF programs, the compiler can generate machine code that exceeds the architecture's limits, leading to arbitrary code execution.
The attack vector is local, requiring an attacker to have access to the vulnerable system. The complexity of the attack is low, as it does not require significant skill or resources. The privileges required are also low, making it easier for an attacker to exploit the vulnerability.
Risk & Impact Analysis
Risk to organizations includes the potential for arbitrary code execution, leading to unauthorized access and control over affected systems. The blast radius could be significant, especially in environments where the Linux kernel is extensively used. Given the high CVSS score and the nature of the vulnerability, organizations should address this vulnerability in their priority patch cycle.
Organizations should schedule remediation promptly to avoid the risks associated with this vulnerability. The low attack complexity combined with the potential for high impact necessitates quick action.
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 versions from 3.16 to below 4.14.251, 4.15 to below 4.19.211, 4.20 to below 5.4.153, 5.5 to below 5.10.71, and 5.11 to below 5.14.10. Additionally, several NetApp firmware versions and Debian distributions are also affected.
Mitigation & Remediation
Organizations should ensure that they apply the necessary patches to remediate CVE-2021-38300. The versions to upgrade to include Linux kernel version 5.4.10 or later. If patches are unavailable, organizations should consider implementing configuration hardening and network controls to mitigate potential exploitation until the patch can be applied.
For further guidance on vulnerability management, organizations can refer to our comprehensive vulnerability management program design.
Detection Guidance
Monitoring for logs that indicate the execution of unprivileged cBPF programs could provide early warning signs of exploitation attempts. Additionally, organizations should look for any behavioral anomalies that could signal unauthorized code execution within the kernel context.
AppSecure Threat Intelligence Insight
CVE-2021-38300 represents a significant risk to systems using affected versions of the Linux kernel. Its potential for arbitrary code execution within the kernel context highlights the importance of maintaining updated software. Security teams should prioritize regular patching and vulnerability assessments to mitigate such risks.
Organizations can benefit from conducting regular penetration testing to identify potential vulnerabilities before they can be exploited.
Additionally, organizations should consider implementing a comprehensive continuous penetration testing strategy to ensure ongoing security effectiveness.
In conclusion, CVE-2021-38300 serves as a reminder of the importance of maintaining timely updates and proactive security measures to protect 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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