CVE-2021-35942 is a critical vulnerability found in the GNU C Library (glibc) affecting versions up to 2.33. It can cause crashes or arbitrary memory reads when the wordexp function is called with untrusted, crafted patterns. This vulnerability arises due to the improper use of atoi instead of strtoul, which can lead to incorrect calculations. As a result, organizations face risks that include potential denial of service and information disclosure.
The vulnerability has a CVSS score of 9.1, classifying it as critical. This high score indicates a severe risk, particularly as it can be exploited over the network with low complexity and no required privileges or user interaction. Consequently, organizations must treat this issue with utmost urgency.
Exploitation of this vulnerability has been confirmed, and while it is not currently in the Known Exploited Vulnerabilities (KEV) catalog, it is essential for defenders to prioritize patching immediately. The real-world implications could lead to significant operational disruptions.
Given the nature of this vulnerability, organizations utilizing affected versions of glibc should schedule remediation as soon as possible to mitigate potential risks.
Vulnerability Details
The wordexp function in glibc up to version 2.33 is vulnerable to improper input handling. When called with crafted patterns, it may lead to application crashes or unauthorized memory access. The specific root cause is attributed to the use of atoi instead of strtoul, which fails to enforce proper boundaries on input values. The vulnerability has a CVSS 3.1 score of 9.1, classified under CWE-190 and CWE-704.
Technical Analysis
The attack vector for this vulnerability is network-based, allowing remote attackers to exploit it with low complexity. The vulnerability requires no privileges, and user interaction is also not necessary. If successfully exploited, it can cause high confidentiality and availability impacts while maintaining no integrity impact. This vulnerability's nature allows attackers to create conditions for denial of service through crafted inputs.
Risk & Impact Analysis
Risk to organizations includes potential denial of service and exposure of sensitive information. The blast radius could affect all services utilizing glibc, particularly in environments where untrusted input is processed. Given its critical severity, organizations should address this vulnerability in their priority patch cycle, especially considering its ease of exploitation.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability affects glibc versions up to 2.33, including components from NetApp and Debian. Organizations should ensure they upgrade to patched versions as soon as possible.
Mitigation & Remediation
To mitigate this vulnerability, organizations should apply the latest patches provided by their vendors. For those using glibc, it is critical to upgrade to versions beyond 2.33. If a patch is not immediately available, consider implementing input validation and sanitization measures as workarounds. Utilizing application security assessments can help identify and remediate potential issues.
Detection Guidance
Organizations can monitor for unusual behavior in applications utilizing glibc, particularly focusing on logs for abnormal terminations or memory access attempts. Behavioral anomalies may indicate attempts to exploit this vulnerability. Network signatures can also be developed to detect exploitation attempts.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-35942 lies in its demonstration of the risks associated with improper input handling in libraries. It highlights the need for stringent validation mechanisms across all software components. Security teams must learn from this incident to improve defensive postures, ensuring that all software dependencies are regularly reviewed and patched. Strategic defensive takeaways include adopting a proactive approach to vulnerability management and incorporating regular vulnerability management programs in their security frameworks.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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