CVE-2023-3446 is a medium-severity vulnerability in OpenSSL, identified on July 19, 2023. This vulnerability allows applications that use the functions DH_check(), DH_check_ex(), or EVP_PKEY_param_check() to potentially experience long delays when checking excessively long Diffie-Hellman (DH) keys or parameters. The attack vector is network-based, and the impact is primarily a Denial of Service (DoS) through inefficient processing.
The vulnerability arises when an application, relying on untrusted sources for DH keys or parameters, inadvertently allows excessively long modulus values during validation. While OpenSSL typically caps the modulus length at 10,000 bits, the DH_check() function performs multiple checks that can still utilize an excessively large modulus. This can lead to significant delays, making the application vulnerable to a DoS attack.
Organizations should prioritize remediation of this vulnerability as the availability impact is considered low, but the potential for service disruption is non-negligible. Immediate patching is recommended to prevent exploitation by malicious actors.
As of now, there is no known public exploit for this vulnerability, but organizations should remain vigilant. The OpenSSL SSL/TLS implementation is not affected by this issue, and the FIPS providers of OpenSSL 3.0 and 3.1 are also unaffected.
Vulnerability Details
The official description of CVE-2023-3446 highlights that checking excessively long DH keys or parameters may lead to significant delays. The functions DH_check(), DH_check_ex(), and EVP_PKEY_param_check() may be exploited when they process parameters from untrusted sources. The vulnerability is classified under CWE-606 and CWE-1333.
The CVSS score for this vulnerability is 5.3, indicating a medium severity level, with the following metrics:
Metric | Value |
|---|---|
Attack Vector | Network |
Attack Complexity | Low |
Privileges Required | None |
User Interaction | None |
Availability Impact | Low |
Technical Analysis
The root cause of this vulnerability lies in the way OpenSSL checks the DH parameters. Even when it determines that the modulus length is too large, it continues to perform checks that utilize that modulus, leading to performance degradation.
The attack vector is network-based, and the complexity of the attack is considered low. No privileges are required, and there is no need for user interaction. The potential impact on availability is low, but organizations should be aware of the risk of service disruption.
Risk & Impact Analysis
Risk to organizations includes the potential for denial of service attacks if an attacker can supply excessively large DH parameters. Given the medium severity of this vulnerability, organizations should address this issue in their priority patch cycle.
The blast radius of this vulnerability can extend beyond a single application, as any application using the affected OpenSSL functions may also be vulnerable. The urgency for mitigation is moderate, as organizations should schedule remediation promptly to avoid potential disruptions.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions of OpenSSL prior to the patch are affected, specifically versions 1.0.2, 1.1.1, 3.0.0, 3.1.0, and 3.1.1. Organizations should ensure they are running the patched versions to mitigate this vulnerability.
Mitigation & Remediation
Organizations should prioritize patching OpenSSL to a version that addresses this vulnerability. The recommended action is to upgrade to the latest version available from OpenSSL. If an immediate upgrade is not feasible, organizations should implement network controls to limit exposure to untrusted DH parameters.
For further assistance in validating the security of your OpenSSL implementation, organizations can consider engaging in penetration testing services.
Detection Guidance
Monitoring for unusual delays in DH key processing can be an indicator of exploitation attempts. Additionally, organizations should log any suspicious activity related to the use of DH parameters in their applications.
AppSecure Threat Intelligence Insight
CVE-2023-3446 represents a critical reminder of the importance of validating parameters obtained from untrusted sources. This incident underscores the necessity for organizations to implement strict checks and balances in their cryptographic libraries.
Security teams can benefit from reviewing their current cryptographic practices and ensuring they are aligned with industry standards. For more insights, organizations may refer to our guide on penetration testing methodology and vulnerability management programs.
Furthermore, organizations should establish robust incident response protocols to address any potential exploitation attempts swiftly. For enhanced security, consider exploring our offerings on API security testing and cloud penetration testing to further strengthen your defenses.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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