CVE-2021-4160 is classified as a medium severity vulnerability that affects OpenSSL versions 1.0.2, 1.1.1, and 3.0.0, specifically on MIPS platforms. This vulnerability allows for a carry propagation bug in the MIPS32 and MIPS64 squaring procedure, impacting several elliptic curve (EC) algorithms, including default TLS 1.3 curves. Although the impact has not been fully analyzed, it is important to recognize that the prerequisites for exploitation are considered unlikely and include the reuse of private keys.
Analysis indicates that while attacks against RSA and DSA due to this defect would be very difficult and unlikely to occur, attacks against Diffie-Hellman (DH) are theoretically feasible, albeit challenging. Most of the work to deduce information about a private key can be performed offline. However, for an attack to be meaningful, the server would need to share the DH private key across multiple clients, which is not an option since the fix for CVE-2016-0701.
The vulnerability was published on January 28, 2022, and has since been addressed in the OpenSSL releases 1.1.1m and 3.0.1, both released on December 15, 2021. For the 1.0.2 version, the fix is available under a specific git commit for premium support customers and will be made available in the upcoming 1.0.2zc release. Organizations using affected versions should ensure timely updates to mitigate risks associated with this vulnerability.
Given the nature of this vulnerability, organizations should prioritize patching immediately.
Vulnerability Details
The official CVE description highlights a carry propagation bug in the squaring procedure for MIPS32 and MIPS64, impacting various EC algorithms. The CVSS score for this vulnerability is 5.9, indicating a medium severity level. The attacks are primarily network-based and require high complexity with no privileges or user interactions. The confidentiality impact is deemed high, while integrity and availability impacts are none.
Technical Analysis
The root cause of this vulnerability lies in the carry propagation bug that arises during the squaring procedure on MIPS architectures. The attack vector is primarily network-based with a high attack complexity. No privileges are required for exploitation, and user interaction is not necessary. The impact on confidentiality is significant, while integrity and availability remain unaffected.
Risk & Impact Analysis
The real-world deployment risk associated with CVE-2021-4160 is moderate due to the unlikely prerequisites for successful exploitation. However, organizations should remain vigilant of the potential for attacks leveraging this vulnerability. The urgency to address this vulnerability is categorized as medium, aligning with the CVSS score and the nature of the threat.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects OpenSSL versions 1.0.2, 1.1.1 (up to but not including 1.1.1m), and 3.0.0. The specific version ranges are: OpenSSL 1.1.1m and 3.0.1 address this issue.
Mitigation & Remediation
Organizations should ensure they are using the latest patched versions of OpenSSL. The versions to upgrade to include OpenSSL 1.1.1m or 3.0.1. If patching is not immediately possible, consider implementing configuration hardening and network controls to limit exposure.
Detection Guidance
Monitoring for unusual behavior in cryptographic operations and reviewing logs for anomalies related to the use of affected OpenSSL versions can aid in detecting potential exploitation attempts.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-4160 lies in the need for organizations to continuously monitor and patch cryptographic libraries. This vulnerability represents a trend towards increased scrutiny of cryptographic implementations. Security teams should take lessons from this incident to enhance their vulnerability management programs and prioritize the security of cryptographic algorithms.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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