CVE-2021-26708 is a high-severity vulnerability discovered in the Linux kernel before version 5.10.13. This vulnerability allows for local privilege escalation due to multiple race conditions in the AF_VSOCK implementation. The underlying cause of these race conditions is improper locking in the source file net/vmw_vsock/af_vsock.c. These issues were implicitly introduced in the commits that added support for VSOCK multi-transport.
The CVSS score for this vulnerability is 7, indicating a high severity level. This score reflects the potential impact on confidentiality, integrity, and availability, all rated as high. The presence of multiple race conditions makes it crucial for organizations to address this vulnerability promptly.
Risk to organizations includes unauthorized access to sensitive information and systems through local exploitations. Attackers may leverage this vulnerability to gain elevated privileges, compromising system integrity and potentially allowing for further attacks.
Organizations should prioritize patching immediately. The vulnerability has been documented, and patches are available for affected systems. It is crucial to validate that all systems are updated to mitigate the associated risks.
Vulnerability Details
The official CVE description states that this vulnerability allows for local privilege escalation in the Linux kernel versions before 5.10.13. The CVSS version 3.1 score includes an attack vector of 'LOCAL,' indicating that an attacker must have local access to exploit the vulnerability. The attack complexity is rated as 'HIGH,' and only low privileges are required to execute the exploit.
The vulnerability affects several components, notably the Linux kernel itself and various NetApp products such as the aff_baseboard_management_controller and cloud_backup. The vulnerability was published on February 5, 2021, and has been classified under CWE-667, which pertains to improper locking.
Technical Analysis
The root cause of CVE-2021-26708 is a series of race conditions stemming from incorrect locking mechanisms in the AF_VSOCK implementation of the Linux kernel. The attack vector is local, requiring an attacker to have physical or shell access to the targeted system. The attack complexity is rated as high due to the specific conditions needed to exploit the race conditions effectively.
To exploit this vulnerability, the attacker requires low-level privileges, and user interaction is not necessary. The impacts on confidentiality, integrity, and availability are all rated high. This means that the successful exploitation of the vulnerability could lead to significant data leaks, unauthorized modifications, and disruptions in service availability.
Risk & Impact Analysis
The real-world deployment risk associated with CVE-2021-26708 is significant. Organizations using affected versions of the Linux kernel or NetApp products face potential exploitations that could lead to unauthorized access and control over their systems. The blast radius is considerable, especially in environments where sensitive data is processed or stored.
Given the high CVSS score and the potential for exploitation, organizations should assess the urgency of addressing this vulnerability. Patching should be a priority in the upcoming patch cycle to minimize exposure to attacks.
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects all versions of the Linux kernel prior to 5.10.13. Additionally, various NetApp products, including the aff_baseboard_management_controller and cloud_backup, are also impacted. Organizations should ensure that their systems are updated to the latest versions to mitigate these risks.
Mitigation & Remediation
To remediate this vulnerability, organizations should apply patches and updates provided by the Linux kernel maintainers and NetApp. Specific updates addressing CVE-2021-26708 can be found in the ChangeLog for version 5.10.13 and subsequent releases.
If patches are not immediately available, organizations should implement workarounds such as restricting access to vulnerable components, enhancing monitoring for unusual activity, and considering configuration hardening to reduce exposure.
Organizations should validate remediation through penetration testing to identify similar weaknesses.
Detection Guidance
Organizations should monitor logs for indicators of exploitation, including unusual access patterns and unauthorized privilege escalations. Behavioral anomalies in user accounts should also be closely scrutinized, particularly for accounts that have access to sensitive systems.
Network signatures corresponding to the exploitation attempts should be developed and monitored. Additionally, any changes to system configurations or files should be logged and reviewed.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-26708 lies in its demonstration of vulnerabilities in the Linux kernel's handling of local security. This incident highlights the importance of robust security practices in kernel development, especially regarding multi-transport features.
Security teams should take this as a lesson to enhance testing and validation processes for kernel updates. Continuous monitoring for vulnerabilities and a proactive approach to security will help mitigate similar risks in the future.
For further insights on securing your Linux environments, organizations can refer to our Linux security best practices blog post, which provides guidelines on maintaining a secure infrastructure.
Additionally, organizations should consider engaging in penetration testing methodology to ensure their defenses are robust against emerging threats.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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