CVE-2021-20194 is a high-severity vulnerability affecting the Linux kernel, specifically in versions higher than 5.2. This vulnerability arises from specific configurations in the kernel where the BPF syscall is enabled. If the kernel is compiled with the parameters CONFIG_BPF_SYSCALL, CONFIG_BPF, CONFIG_CGROUPS, CONFIG_CGROUP_BPF enabled, and CONFIG_HARDENED_USERCOPY not set, a local user can exploit this condition. The flaw is due to a bug in the __cgroup_bpf_run_filter_getsockopt() function, which can result in a heap overflow.
The severity of this vulnerability is classified as high, with a CVSS score of 7.8. This indicates that while the attack vector is local and requires low complexity and privileges, the potential impacts are significant. Risk to organizations includes denial of service, and potentially unauthorized privilege escalation, which could have severe implications on system integrity and availability.
According to the current intelligence, there is no known public exploit for this vulnerability, and it is not actively being exploited in the wild. Nevertheless, organizations should prioritize remediation due to the high-risk nature of this vulnerability and the potential for exploitation if it becomes known.
Organizations should prioritize patching immediately. The urgency for defenders is underscored by the potential consequences this vulnerability poses to system security.
Vulnerability Details
The official description of CVE-2021-20194 highlights the conditions that lead to this vulnerability. The attack vector is local, requiring low complexity and privileges, with no user interaction required. The potential impacts on confidentiality, integrity, and availability are all rated high, making this a critical issue for any affected systems.
The CVSS score of 7.8 is indicative of a high severity level, emphasizing the importance of immediate remediation. This vulnerability affects several products, including the Linux kernel, OpenShift Container Platform, and Red Hat Enterprise Linux.
Technical Analysis
The root cause of CVE-2021-20194 is linked to the improper handling of BPF (Berkeley Packet Filter) execution, leading to a bug in the function responsible for managing socket options. The attack complexity is low, as local access is sufficient for an attacker to leverage this flaw. Privileges required for exploitation are also low, meaning that a standard user could potentially exploit this vulnerability.
No user interaction is required to exploit this vulnerability, which increases the risk significantly. The impacts on confidentiality, integrity, and availability are all rated high, indicating that a successful exploit could lead to severe disruption and unauthorized access.
Risk & Impact Analysis
The risk to organizations includes the possibility of denial of service, which can significantly disrupt operations. Additionally, the potential for privilege escalation could allow an attacker to gain unauthorized access to sensitive data or systems, leading to further exploitation. Given the nature of the Linux kernel's role in system architecture, the blast radius of such an attack could be extensive.
Organizations should assess their exposure to this vulnerability and prioritize remediation efforts based on the high CVSS score and the potential impact on their operations. The urgency for addressing this vulnerability is high, and organizations should include it in their immediate patch cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions include the Linux kernel versions higher than 5.2, specifically when compiled with certain configurations. Additionally, the following products are affected: Red Hat OpenShift Container Platform versions 4.4, 4.5, and 4.6, as well as Red Hat Enterprise Linux version 8.0.
Mitigation & Remediation
Organizations should update their systems to the latest patched versions of the affected products. For Red Hat, patches are available for OpenShift Container Platform and Enterprise Linux. In cases where immediate patching is not possible, organizations should consider implementing workarounds, such as disabling the affected BPF features or applying configuration hardening to limit exposure.
For further technical guidance and to ensure comprehensive security, organizations are encouraged to engage in penetration testing to assess their environment against this vulnerability.
Detection Guidance
Organizations should monitor logs for any unusual activity related to socket operations and BPF executions. Behavioral anomalies could indicate attempts to exploit this vulnerability. Additionally, monitoring network signatures for traffic patterns associated with the exploitation of heap overflow vulnerabilities is recommended.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-20194 underscores the importance of robust security practices surrounding kernel configurations. As attackers increasingly target kernel-level vulnerabilities, security teams must remain vigilant in monitoring and patching systems.
This vulnerability reflects a trend of escalated risks associated with improper configurations in Linux environments. Organizations should learn from these incidents and incorporate proactive measures into their security posture.
Strategic defensive takeaways include regular audits of kernel configurations, ensuring adherence to security best practices, and investing in continuous security assessments such as continuous penetration testing to identify and mitigate vulnerabilities proactively.
Organizations are encouraged to reference their vulnerability management programs and adapt to this evolving threat landscape by enhancing their security infrastructure.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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