CVE-2021-3715 is a high-severity vulnerability found in the "Routing decision" classifier within the Linux kernel's Traffic Control networking subsystem. This flaw occurs due to an improper handling of changing classification filters, resulting in a use-after-free condition. The impact of this vulnerability is significant as it allows unprivileged local users to escalate their privileges on the system, posing a serious threat to confidentiality, integrity, and availability.
The CVSS score for this vulnerability is 7.8, indicating a high level of risk that organizations should not underestimate. Given the potential for privilege escalation, it is essential for defenders to act promptly, as the implications of non-remediation can be severe, leading to unauthorized access and potential system compromise.
As of now, there is a known exploit for this vulnerability, which increases the urgency for organizations to address it. The exploitation status is critical, and defenders should prioritize remediation to protect their systems from potential attacks.
Organizations should prioritize patching immediately to mitigate risks associated with CVE-2021-3715 and ensure their systems remain secure.
Vulnerability Details
The vulnerability allows unprivileged local users to escalate their privileges due to a flaw in the Linux kernel's Traffic Control subsystem. The flaw is categorized as a use-after-free condition, which is a critical type of vulnerability that can lead to severe security issues.
The CVSS 3.1 score for this vulnerability is 7.8, indicating high severity. The breakdown of the CVSS vector indicates that the attack vector is local, the attack complexity is low, and the privileges required are minimal. The impacts on confidentiality, integrity, and availability are all rated as high.
The vulnerability affects the Linux kernel versions from 3.18 up to but not including 4.4.218, as well as several other ranges up to version 5.5.14. The flaw was published on March 2, 2022.
Technical Analysis
The root cause of CVE-2021-3715 is related to the improper handling of classification filters, which leads to a use-after-free condition. This vulnerability arises when the kernel fails to properly manage memory during the filtering process, allowing an attacker to exploit this oversight.
The attack vector for this vulnerability is local, meaning that an attacker must have access to the target system. The attack complexity is classified as low, which implies that exploitation requires minimal technical skills. Additionally, the privileges required to exploit this vulnerability are low, meaning that unauthorized users can potentially escalate their privileges without needing elevated permissions.
User interaction is not required for exploitation, making this vulnerability particularly dangerous, as it can be exploited without any involvement from the targeted user. The impacts on confidentiality, integrity, and availability are all rated as high, highlighting the potential for severe damage if exploited.
Risk & Impact Analysis
The risk to organizations includes unauthorized privilege escalation, which can lead to data breaches and significant disruptions. This vulnerability has the potential to affect a wide range of systems, especially those running vulnerable versions of the Linux kernel.
The blast radius is extensive, as the kernel is a core component of many Linux-based systems. Failure to address this vulnerability could result in widespread exploitation, thereby compromising the integrity of entire networks.
Given the CVSS score of 7.8 and the presence of known exploits, organizations should assess this vulnerability's urgency as critical. Immediate action is required to mitigate the risks associated with CVE-2021-3715.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerable versions of the Linux kernel include all versions from 3.18 up to but not including 4.4.218, as well as specific ranges up to 5.5.14. Organizations should ensure that they are running patched versions to avoid exposure to this vulnerability.
Mitigation & Remediation
Organizations should prioritize patching the Linux kernel to versions that contain fixes for CVE-2021-3715. If immediate patching is not feasible, consider applying workarounds such as restricting access to systems running vulnerable kernel versions.
For comprehensive security, organizations may also engage in penetration testing to validate remediation efforts and identify other potential vulnerabilities.
Detection Guidance
Monitoring logs for unauthorized access attempts and unusual privilege escalation events can aid in the detection of exploitation attempts related to this vulnerability. Additionally, organizations should implement behavioral anomaly detection to identify potential exploitation.
AppSecure Threat Intelligence Insight
CVE-2021-3715 represents a critical vulnerability within the Linux ecosystem that underscores the importance of proactive vulnerability management. Security teams should leverage insights from this incident to enhance their defensive strategies.
Organizations should incorporate lessons learned from this vulnerability into their vulnerability management program to improve their overall security posture.
Moreover, continuous monitoring and regular security assessments, including penetration testing, can help organizations stay ahead of emerging threats and vulnerabilities.
To further enhance defensive capabilities, organizations should consider leveraging continuous penetration testing methodologies to ensure ongoing security validation.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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