CVE-2021-33033 is a high-severity vulnerability that affects the Linux kernel versions prior to 5.11.14. This vulnerability allows an attacker to exploit a use-after-free condition in the function cipso_v4_genopt within the file net/ipv4/cipso_ipv4.c. The mishandling of the CIPSO and CALIPSO refcounting for DOI definitions results in the potential for writing an arbitrary value.
The Common Vulnerability Scoring System (CVSS) score for this vulnerability is 7.8, categorizing it as high severity. The implications of this vulnerability can be severe, with risks to confidentiality, integrity, and availability all rated high. Given that it permits local attack vectors with low complexity and requires low privileges, the risk to organizations is considerable.
Organizations using affected versions of the Linux kernel should prioritize immediate patching to mitigate the risk. The vulnerability has been publicly disclosed, and no known exploits are currently available, but the potential for exploitation remains a significant concern.
Urgency for defenders cannot be understated, as the implications of this vulnerability could lead to unauthorized access and system compromise.
Vulnerability Details
The Linux kernel before version 5.11.14 has a use-after-free vulnerability in the function cipso_v4_genopt due to mishandled CIPSO and CALIPSO refcounting for DOI definitions. This leads to writing an arbitrary value, which could potentially compromise the integrity of the system.
The CVSS score of 7.8 reflects a high severity level, indicating that this vulnerability poses a serious threat to the security of affected systems. The vulnerability has been assigned a CWE classification of CWE-416, which denotes use-after-free vulnerabilities.
This vulnerability was published on May 14, 2021, and affects all versions of the Linux kernel prior to 5.11.14. The potential consequences of exploitation include unauthorized access, data corruption, and system instability.
Technical Analysis
The root cause of CVE-2021-33033 stems from incorrect reference counting in the Linux kernel. Specifically, when CIPSO and CALIPSO DOI definitions are processed, the system fails to properly manage memory, leading to a use-after-free condition. This mishandling can be exploited locally, allowing attackers with low privileges to leverage this flaw.
The attack vector is local, requiring the attacker to have access to the system. The complexity of the attack is low, as no special conditions or user interaction is required. The impact on confidentiality, integrity, and availability is high, as exploitation could lead to arbitrary code execution and system crashes.
Risk & Impact Analysis
The real-world risk associated with CVE-2021-33033 is significant. Organizations using vulnerable versions of the Linux kernel may face unauthorized data access, system crashes, and potential data loss. The blast radius could be extensive, impacting multiple systems if exploited in a networked environment.
Given the high CVSS score and the characteristics of this vulnerability, organizations should prioritize patching immediately. Delaying remediation could lead to serious consequences, including exploitation by attackers leveraging this flaw.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions of the Linux kernel prior to 5.11.14 are affected by this vulnerability. Organizations should ensure that their systems are updated accordingly to prevent potential exploitation.
Mitigation & Remediation
To remediate CVE-2021-33033, organizations should patch their systems to Linux kernel version 5.11.14 or later. This patch addresses the use-after-free vulnerability, thus eliminating the risk associated with the flaw. Additionally, organizations may consider implementing configuration hardening and network controls to further mitigate risks.
For further guidance on security assessment, organizations can refer to our application security assessment services, which can help identify similar vulnerabilities in your environment.
Detection Guidance
To detect potential exploitation of CVE-2021-33033, organizations should monitor their systems for unusual memory access patterns and behaviors characteristic of use-after-free vulnerabilities. Log indicators may include abnormal application crashes or unexpected access to memory regions.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-33033 highlights the importance of robust memory management practices in the development of kernel-level software. This vulnerability represents a pattern of common weaknesses that can lead to severe security issues if not addressed.
Security teams should take this incident as a lesson in proactive vulnerability management. Regular audits and implementing a vulnerability management program can significantly reduce risk exposure.
Additionally, employing a comprehensive penetration testing approach, such as penetration testing, can help uncover vulnerabilities before malicious actors can exploit them.
In conclusion, CVE-2021-33033 serves as a critical reminder of the vulnerabilities that can arise from improper memory management and the necessity for organizations to remain vigilant in their security practices.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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