CVE-2009-0124 in tqsllib
Summary
by MITRE
The tqsl_verifyDataBlock function in openssl_cert.cpp in American Radio Relay League (ARRL) tqsllib 2.0 does not properly check the return value from the OpenSSL EVP_VerifyFinal function, which allows remote attackers to bypass validation of the certificate chain via a malformed SSL/TLS signature, a similar vulnerability to CVE-2008-5077.
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Analysis
by VulDB Data Team • 08/25/2019
The vulnerability identified as CVE-2009-0124 resides within the American Radio Relay League's tqsllib 2.0 library, specifically in the tqsl_verifyDataBlock function located in openssl_cert.cpp. This flaw represents a critical security oversight that directly impacts the certificate validation process used by the library. The issue manifests when the function fails to properly validate the return value from OpenSSL's EVP_VerifyFinal function, creating a potential pathway for malicious actors to circumvent essential certificate chain validation mechanisms.
The technical nature of this vulnerability stems from improper error handling within the cryptographic verification process. When EVP_VerifyFinal is invoked as part of the certificate validation workflow, it returns a specific status code indicating whether the signature verification was successful. The tqsllib implementation fails to check this return value properly, allowing the function to proceed with certificate validation even when the underlying signature verification has failed. This oversight creates a scenario where malformed SSL/TLS signatures can pass validation, effectively undermining the entire certificate trust model. The vulnerability closely parallels CVE-2008-5077, which demonstrated similar weaknesses in OpenSSL's handling of signature verification, indicating a pattern of insufficient error checking in cryptographic operations.
From an operational perspective, this vulnerability presents significant risks to systems relying on tqsllib for certificate validation, particularly within radio communication and amateur radio networks where certificate integrity is crucial for maintaining secure communications. Remote attackers can exploit this weakness to inject malicious certificates or manipulate signature validation processes, potentially leading to man-in-the-middle attacks or unauthorized access to sensitive radio communication systems. The impact extends beyond simple certificate validation failure, as it compromises the fundamental security assumptions underlying the SSL/TLS certificate chain verification process. This weakness could enable attackers to establish fraudulent communication channels or bypass authentication mechanisms that depend on proper certificate validation.
The vulnerability aligns with CWE-252, which addresses "Unchecked Return Value," and represents a classic example of insufficient error handling in cryptographic contexts. From an ATT&CK framework perspective, this weakness maps to techniques involving credential access and privilege escalation through manipulation of validation processes. Organizations using tqsllib 2.0 should implement immediate mitigations including updating to patched versions of the library, implementing additional validation layers, and monitoring for suspicious certificate validation activities. The recommended approach involves ensuring all return values from cryptographic verification functions are properly checked and that appropriate error handling mechanisms are implemented to prevent the execution flow from continuing when verification failures occur.
Security practitioners should also consider implementing network-level monitoring to detect anomalous certificate validation patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of thorough error handling in cryptographic implementations and serves as a reminder of the potential consequences when proper validation checks are omitted from security-sensitive code paths. Organizations should conduct comprehensive audits of their cryptographic libraries to identify similar unchecked return value scenarios that could present analogous security risks.