CVE-2024-4603 is a medium-severity vulnerability related to DSA key checking in OpenSSL. The vulnerability arises when applications utilize the functions EVP_PKEY_param_check() or EVP_PKEY_public_check() to validate DSA public keys or parameters. These functions can lead to significant delays if excessively long DSA keys or parameters are provided, particularly if the keys are sourced from untrusted origins. As a result, attackers may exploit this behavior to mount Denial of Service attacks, causing applications to become unresponsive.
The CVSS score for this vulnerability is 5.3, indicating a medium level of risk. This score reflects the potential for disruption to services rather than data exposure. Although OpenSSL itself does not call these functions on untrusted keys, applications that directly invoke them may find themselves at risk. Organizations relying on OpenSSL for cryptographic operations should be particularly vigilant.
Given the nature of this vulnerability, it is crucial for organizations to address it promptly. While active exploitation is not currently reported, the potential impact on service availability necessitates immediate attention. Organizations should prioritize reviewing their use of DSA key validation functions and implement necessary patches or workarounds.
The urgency for remediation is rated as medium. Organizations are advised to schedule remediation efforts in their maintenance cycles to mitigate potential risks associated with this vulnerability.
Vulnerability Details
This vulnerability allows applications using the functions EVP_PKEY_param_check() or EVP_PKEY_public_check() to check DSA public keys or DSA parameters to experience long delays when excessively long keys are provided. The OpenSSL 3.0 and 3.1 FIPS providers are specifically affected, as they do not limit the modulus size during these checks.
The vulnerability is classified under CWE-606: Unchecked Input for Operations on Critical Resources and CWE-834: Excessive Iteration. This classification underscores the risks involved with processing untrusted input and the potential for Denial of Service.
Published on May 16, 2024, this vulnerability is pending further analysis. Organizations are encouraged to monitor for updates regarding mitigation strategies.
Technical Analysis
The root cause of CVE-2024-4603 is the lack of restrictions on the size of DSA parameters during validation checks. While OpenSSL prevents the usage of excessively large public keys (over 10,000 bits) for signatures, it does not enforce similar limits during the checks performed by EVP_PKEY_param_check() and EVP_PKEY_public_check().
The attack vector is network-based, allowing attackers to exploit this vulnerability remotely. The attack complexity is low, requiring minimal effort to trigger the denial of service condition. No special privileges or user interaction are necessary for exploitation. The potential impact on availability is rated as low, given that the application may become unresponsive under specific conditions.
Risk & Impact Analysis
Risk to organizations includes disruption of service availability, particularly for applications that rely on DSA key validation functions. The potential for Denial of Service attacks highlights the need for organizations to assess their exposure to this vulnerability, especially if they process untrusted DSA keys or parameters. The blast radius could encompass any application utilizing these OpenSSL functions, leading to broader service disruptions.
The urgency for organizations to address this vulnerability is classified as medium. While there is no active exploitation reported, the potential for service disruption mandates that organizations include this in their patching and remediation efforts.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions include OpenSSL 3.0 and 3.1 FIPS providers. Organizations using these versions should review their implementations and apply necessary updates.
Mitigation & Remediation
Organizations should prioritize reviewing their application code to ensure DSA key validation functions are not called with untrusted input. Immediate patching of OpenSSL to the latest version that addresses this vulnerability is essential. For those unable to apply patches, consider implementing input validation to restrict the size of DSA keys and parameters.
For comprehensive security assessments, organizations can consider integrating penetration testing services as part of their remediation strategy.
Detection Guidance
Monitoring logs for unusual delays during DSA key validation processes can be an indicator of potential exploitation attempts. Look for patterns of excessive computational time associated with specific applications. Behavioral anomalies in application response times could also signify attempts to exploit this vulnerability.
AppSecure Threat Intelligence Insight
CVE-2024-4603 highlights the importance of input validation in cryptographic functions. Organizations should evaluate their use of cryptographic libraries and ensure they are not susceptible to excessive input sizes. This vulnerability serves as a reminder that even widely used libraries like OpenSSL can harbor risks if not properly configured.
To enhance their security posture, organizations can benefit from establishing a robust vulnerability management program that includes regular reviews and assessments of cryptographic implementations.
Additionally, organizations should consider investing in penetration testing methodologies to proactively identify and mitigate such vulnerabilities before they can be exploited.
In conclusion, CVE-2024-4603 underscores the necessity for continual vigilance in security practices surrounding cryptographic operations. Organizations must prioritize timely updates and rigorous testing to safeguard their systems.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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