CVE-2023-6237 is a medium-severity vulnerability in OpenSSL that arises from the processing of excessively long invalid RSA public keys. This vulnerability allows applications utilizing the EVP_PKEY_public_check() function to potentially experience long delays, especially when the RSA key is sourced from untrusted origins. Such delays may lead to a Denial of Service (DoS) condition.
The exploitation of this vulnerability is contingent upon an application calling the EVP_PKEY_public_check() function with an RSA public key that is invalid and excessively long. The primary risk to organizations includes potential service interruptions due to unresponsive applications, particularly if the RSA public key verification process is invoked under these circumstances.
The specific risk involved is categorized as medium severity with a CVSS score of 5.9. Given this score, organizations must evaluate their use of OpenSSL and implement necessary mitigations against potential service disruptions. Organizations should prioritize patching immediately.
As of the latest analysis, this vulnerability is marked as 'Awaiting Analysis.' Therefore, the urgency for patching will depend on the forthcoming disclosures by OpenSSL on the remediation of this vulnerability.
Vulnerability Details
The vulnerability allows for Denial of Service through the EVP_PKEY_public_check() function, which verifies RSA public keys. When this function is called, it performs a computation to verify that the RSA modulus, n, is composite. For valid RSA keys, this process is quick; however, if n is an excessively large prime, the computation takes significantly longer. Applications calling this function with untrusted RSA keys are thus vulnerable to a denial of service, particularly if the function is invoked under conditions where the input key is invalid and untrusted.
This vulnerability affects the OpenSSL 3.0 and 3.1 FIPS providers but does not impact the SSL/TLS implementation of OpenSSL. The vulnerability is classified under CWE-606, indicating an improper restriction of excessive processing.
Technical Analysis
The root cause of CVE-2023-6237 is the inefficiency in handling excessively long RSA public keys within the EVP_PKEY_public_check() function. The attack vector is through the network, where an attacker can exploit vulnerable applications by providing maliciously crafted RSA public keys. The attack complexity is classified as high, requiring no privileges or user interaction.
While the confidentiality and integrity impacts are rated as none, the availability impact is rated as high, resulting in significant service disruption if exploited. This vulnerability emphasizes the importance of input validation and limits on processing times.
Risk & Impact Analysis
Organizations utilizing OpenSSL should be aware of the real-world risks posed by this vulnerability, particularly in applications that handle RSA public keys from untrusted sources. The potential for a Denial of Service attack can disrupt services, leading to downtime and loss of productivity.
The blast radius for this vulnerability could be significant, especially for applications that rely heavily on RSA public key verification for client authentication or secure communications. Organizations should assess their deployment of OpenSSL in their applications and prioritize patching or remediation based on their risk assessment.
Given the CVSS score of 5.9, organizations are encouraged to address this vulnerability in their priority patch cycle to mitigate potential risks and ensure continued availability of services.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability impacts OpenSSL versions 3.0 and 3.1 FIPS providers. Organizations must ensure that they are running patched versions to mitigate this vulnerability.
Mitigation & Remediation
Organizations using affected versions of OpenSSL should prioritize upgrading to the latest available version that addresses this vulnerability. If immediate patching is not feasible, consider implementing network controls to restrict access to applications using the EVP_PKEY_public_check() function and monitor for unusual behaviors.
For ongoing security assurance, organizations are advised to adopt a comprehensive security strategy including penetration testing to discover and mitigate similar vulnerabilities.
Detection Guidance
Monitoring logs for any anomalies related to the use of the EVP_PKEY_public_check() function can provide early indications of exploitation attempts. Additionally, organizations should implement behavioral analysis tools to detect unusual patterns that may indicate abuse of RSA public key verification processes.
AppSecure Threat Intelligence Insight
CVE-2023-6237 highlights the critical need for robust input validation and control measures to prevent Denial of Service attacks. The implications of this vulnerability serve as a reminder for security teams to regularly assess their systems, especially when dealing with cryptographic operations. It is essential to implement a thorough vulnerability management program to ensure that all security measures are up to date.
It is also vital to stay informed about the latest trends in threat landscapes. Engaging in regular penetration testing methodology can help organizations anticipate and mitigate potential vulnerabilities before they are exploited.
Lastly, collaboration between security teams and developers is crucial in addressing vulnerabilities such as CVE-2023-6237 effectively. Regular training and awareness programs can foster a culture of security within the organization, ensuring that all team members understand the implications of cryptographic vulnerabilities.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
.webp)