A flaw was found in glibc. This vulnerability allows an off-by-one buffer overflow and underflow in getcwd() which may lead to memory corruption when the size of the buffer is exactly 1. A local attacker who can control the input buffer and size passed to getcwd() in a setuid program could use this flaw to potentially execute arbitrary code and escalate their privileges on the system. The severity level of this vulnerability is classified as high, with a CVSS score of 7.8.
Risk to organizations includes the potential for unauthorized access and control over affected systems. Given the nature of this vulnerability, it is critical for organizations to prioritize patching immediately to prevent exploitation. The vulnerability was published on August 24, 2022, and has been modified since then, indicating ongoing concerns surrounding its impact.
As of the current status, there is no known public exploit confirmed for CVE-2021-3999, and it is not included in the Known Exploited Vulnerabilities (KEV) catalog. However, organizations should remain vigilant and apply any available patches as soon as they are released to mitigate potential risks.
The urgency for defenders is heightened due to the high severity of this issue, and organizations are encouraged to address this vulnerability in their priority patch cycle.
Vulnerability Details
CVE-2021-3999 is an off-by-one buffer overflow that affects the getcwd() function within glibc, which is a core component of many Unix-based operating systems. The vulnerability is classified under CWE-193, indicating improper handling of buffers that could lead to memory corruption. The primary impact includes high confidentiality, integrity, and availability risks, all of which are affected by this vulnerability.
The vulnerability is applicable to multiple versions of glibc, specifically versions prior to 2.31, as well as various Debian Linux distributions (10.0 and 11.0) and certain NetApp products. Organizations using these affected systems should assess their environment for potential exposure to this vulnerability.
Technical Analysis
The root cause of CVE-2021-3999 stems from an off-by-one error in the buffer handling within the getcwd() function. An attacker with local access may exploit this flaw by providing a specially crafted input that exceeds the buffer size, leading to memory corruption. The attack vector for this vulnerability is local, requiring low privileges and no user interaction.
The attack complexity is rated as low, meaning that successful exploitation could be achieved with minimal effort. Given that an attacker only needs to have control over the input buffer and the size passed to the function, the barrier to entry for exploiting this vulnerability is relatively low.
Risk & Impact Analysis
The real-world deployment risk associated with CVE-2021-3999 is significant, particularly for systems that operate with setuid programs that can be manipulated locally by an attacker. The potential for privilege escalation means that an attacker could gain elevated access and control over critical system resources, leading to a broader impact on organizational security.
Organizations should evaluate their systems for exposure to this vulnerability and prioritize remediation efforts. The urgency assessment based on the CVSS score indicates that this vulnerability should be addressed in the priority patch cycle to mitigate any risk of exploitation.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of glibc include all versions prior to 2.31. Additionally, Debian Linux distributions 10.0 and 11.0, along with certain NetApp products such as the E-Series Performance Analyzer, NFS Plug-in, and ONTAP software, are also impacted by this vulnerability.
Mitigation & Remediation
To mitigate the risks associated with CVE-2021-3999, organizations should apply the latest patches to glibc and affected Debian and NetApp products. If a patch is unavailable, consider implementing configuration hardening measures and ensuring that setuid programs are reviewed and restricted where possible. Continuous monitoring should also be established to detect any suspicious activities that may indicate exploitation attempts.
Organizations should validate remediation through penetration testing to identify similar weaknesses.
Detection Guidance
Organizations should monitor logs for any anomalies in the behavior of setuid programs that utilize the getcwd() function. Any unexpected crashes or memory corruption errors should be investigated promptly. Additionally, establishing network signatures to detect unusual access patterns can be beneficial in identifying potential exploitation attempts.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-3999 highlights the importance of rigorous memory management practices in software development. This vulnerability represents a broader pattern of memory corruption issues that continue to affect critical software components. Security teams should prioritize secure coding practices and conduct regular code reviews to prevent similar vulnerabilities.
For organizations looking to enhance their security posture, implementing a comprehensive vulnerability management program can help identify and mitigate risks proactively.
Additionally, engaging in penetration testing and regularly reviewing security policies can further strengthen defenses against emerging threats.
Organizations should also stay informed about vulnerabilities similar to CVE-2021-3999 by following industry best practices and leveraging resources such as the VAPT Testing Services Guide to ensure they are prepared to respond effectively.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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