CVE-2021-3864 represents a significant security vulnerability affecting the Debian Linux Kernel. This flaw allows unprivileged local users to exploit the handling of core dumps generated by certain SUID binaries. When such binaries set the real UID equal to the effective UID, and the real GID equal to the effective GID, a child process can inherit a 'dumpable' status that may lead to unauthorized privilege escalation.
The CVSS base score for this vulnerability is 7.0, categorizing it as high severity. The implications of this vulnerability are serious, as it could allow a local attacker to place core dumps in directories owned by root, thereby increasing the risk of privilege escalation. Organizations running affected systems are urged to take immediate action.
As of the last update, no public exploit has been confirmed, but the potential for exploitation is high, and organizations should prioritize remediating this vulnerability. Immediate patching is essential to minimize exposure.
Risk to organizations includes unauthorized access to sensitive data, system integrity compromise, and potential disruption of services. Organizations should prioritize patching immediately.
Vulnerability Details
The vulnerability is characterized as a privilege escalation flaw, specifically identified as CWE-284. It was published on August 26, 2022, and has been classified with a CVSS score of 7.0 indicating a high severity level. The affected products include the Debian Linux Kernel across various versions.
The vulnerability arises from improper handling of the dumpable flag for processes spawned by certain SUID binaries. When these processes crash, their core dumps may be written to unauthorized directories, allowing an unprivileged user to potentially escalate their privileges.
Technical Analysis
The root cause of CVE-2021-3864 lies in the management of core dumps for processes initiated by SUID binaries. If a descendant process of a SUID binary crashes, the core dump will be created in the current working directory, which may be root-owned. The potential for unauthorized access emerges when an unprivileged user gains access to these core dumps.
The attack vector is local, requiring the attacker to have existing access to the system. Attack complexity is high due to the specific prerequisites that must be met, including the correct configuration of SUID binaries. No user interaction is required, and the confidentiality, integrity, and availability impacts are all rated as high.
Risk & Impact Analysis
Organizations should be aware that this vulnerability poses a significant threat to their operational integrity. The blast radius could extend to sensitive data and system configurations, making it critical for affected environments to apply patches promptly. Given the high CVSS score and potential for exploitation, the urgency of remediation is high.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability affects the following systems: all versions of the Linux Kernel, Debian Linux versions 10.0 and 11.0, and Red Hat Enterprise Linux versions 6.0, 7.0, and 9.0.
Mitigation & Remediation
Organizations must apply the latest patches provided by their Linux distributions to remediate this vulnerability effectively. For systems where immediate patching is not feasible, consider implementing additional access controls and monitoring for suspicious activities. Regularly review configurations of SUID binaries to ensure they do not inadvertently expose sensitive directories.
For continuous security, organizations should engage in regular penetration testing. This can be facilitated through continuous penetration testing to identify and remediate similar vulnerabilities proactively.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor log files for unusual core dump activities and analyze behavioral anomalies related to SUID binaries. Network traffic should be inspected for unauthorized access attempts that may indicate exploitation.
AppSecure Threat Intelligence Insight
CVE-2021-3864 highlights the critical need for organizations to maintain strict controls over SUID binaries and their configurations. This vulnerability serves as a reminder of the potential risks associated with improper process management within operating systems.
Security teams should take this incident as a learning opportunity to refine their processes and increase awareness of privilege escalation vulnerabilities. Regular training and awareness programs can significantly enhance the organization's security posture.
For more insights on vulnerability management, organizations can explore our vulnerability management program and the best practices for penetration testing in their environments.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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