CVE-2021-22600 is classified as a double free vulnerability in the Linux Kernel's packet socket implementation. This flaw allows local users to exploit the vulnerability through crafted syscalls, potentially leading to privilege escalation or denial of service. The CVSS score for this vulnerability is 6.6, indicating a medium severity level, which necessitates prompt attention from affected organizations.
Risk to organizations includes the possibility of unauthorized access and service disruption. This vulnerability primarily affects local users and requires low privileges and user interaction for exploitation. Organizations should be aware that failure to remediate this issue can lead to significant operational impacts.
Given the potential implications of this vulnerability, organizations are urged to address this issue in their patch management cycles. Upgrading the kernel past the affected versions is strongly recommended to ensure systems are protected from this vulnerability.
The vulnerability was published on January 26, 2022, and is actively tracked as part of the Known Exploited Vulnerabilities (KEV) catalog. Organizations should prioritize patching immediately to mitigate risks associated with this vulnerability.
Vulnerability Details
The vulnerability allows for a double free bug in the function packet_set_ring() located in the file net/packet/af_packet.c. The CVE description notes that local users can exploit this issue to escalate privileges or cause denial of service. The recommended action is to upgrade the kernel beyond the impacted versions or to rebuild it past commit ec6af094ea28f0f2dda1a6a33b14cd57e36a9755.
The vulnerability's CVSS score is 6.6, with a high attack complexity and low privileges required for exploitation. The confidentiality and integrity impacts are classified as low, while the availability impact is high. This means that although it may be challenging to exploit, if successful, it can severely disrupt service availability.
This vulnerability affects multiple products including various firmware versions from NetApp and the Linux kernel itself. Organizations using Debian versions 9.0 and 10.0 are particularly at risk and should ensure they are on the latest versions.
Technical Analysis
The root cause of CVE-2021-22600 is a flaw in memory management within the Linux kernel's packet socket implementation. Specifically, the double free vulnerability arises when memory is incorrectly freed, leading to potential exploitation by local users.
The attack vector is local, meaning that an attacker must have access to the system to exploit this vulnerability. The attack complexity is classified as high, implying that significant effort may be required to successfully exploit the vulnerability.
Privileges required for exploitation are low, and while user interaction is required, the potential impacts include unauthorized elevation of privileges, which can allow attackers to execute arbitrary code at a higher privilege level.
The confidentiality impact is low, as the vulnerability does not directly expose sensitive information. However, the integrity and availability impacts are classified as high, indicating that successful exploitation could corrupt or deny access to resources.
Risk & Impact Analysis
Real-world deployment risk is significant, particularly for organizations utilizing the affected Debian kernel versions. The blast radius encompasses local systems where the kernel is deployed, and the potential for service disruption raises urgent concerns.
The urgency for remediation is critical due to the vulnerability's inclusion in the KEV catalog, indicating that it is actively exploited in the wild. Organizations should prioritize patching immediately to mitigate potential risks.
This vulnerability's low EPSS score of approximately 0.0011 suggests that while the risk of exploitation exists, it is relatively low compared to other vulnerabilities. Nonetheless, due to the high availability impact, organizations must be vigilant.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | Yes |
Ransomware Use | No |
Affected Versions
The following versions are affected by CVE-2021-22600: Linux Kernel versions 4.14.175 to 4.14.259, 4.19.114 to 4.19.222, 5.4.29 to 5.4.168, 5.5.14 to 5.10.88, and 5.11 to 5.15.11, along with Debian versions 9.0 and 10.0.
Mitigation & Remediation
Organizations should apply updates per vendor instructions to mitigate the risks associated with this vulnerability. Upgrading to the latest kernel version is crucial.
If a patch is not yet available, organizations should consider implementing workarounds, such as configuring network controls to limit access to vulnerable components. Regular monitoring for unusual behavior can also help identify potential exploitation attempts.
For additional guidance on security practices, organizations can refer to our penetration testing services.
Detection Guidance
To detect potential exploitation of CVE-2021-22600, organizations should monitor logs for indicators of unusual behavior related to privilege escalation attempts. Specific behavioral anomalies may include unexpected changes to user privileges or service disruptions.
Network signatures that detect abnormal packet behavior could also provide crucial insights into attempted exploits. System changes that deviate from baseline configurations should be investigated immediately.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-22600 lies in its representation of vulnerabilities in memory management within the Linux kernel, highlighting the ongoing need for robust testing and validation in software development.
This incident reflects a broader trend of privilege escalation vulnerabilities being exploited in local environments. Security teams need to ensure that their systems are resilient against such vulnerabilities by implementing best practices in secure coding.
The strategic defensive takeaway is to prioritize continuous security assessments and ensure that all components are kept up to date with the latest patches.
For further reading on secure development practices, organizations can explore our penetration testing methodology.
Additionally, understanding the importance of a vulnerability management program can further bolster defenses against such vulnerabilities.
Organizations should also remain informed of emerging threats through our 2025 vulnerability exposure severity trends.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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