CVE-2005-1600 in LibTomCrypt
Summary
by MITRE
A "mathematical flaw" in the implementation of the El Gamal signature algorithm for LibTomCrypt 1.0 to 1.0.2 allows attackers to generate valid signatures without having the private key.
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Analysis
by VulDB Data Team • 07/08/2018
The vulnerability identified as CVE-2005-1600 represents a critical cryptographic weakness in the LibTomCrypt library version 1.0 through 1.0.2, specifically affecting implementations of the El Gamal signature algorithm. This mathematical flaw fundamentally compromises the security assumptions underlying public key cryptography by enabling attackers to forge valid signatures without possessing the corresponding private key, thereby undermining the integrity and authenticity guarantees that digital signatures are designed to provide.
The technical flaw stems from an improper implementation of the mathematical operations required for El Gamal signature generation, where certain modular arithmetic computations fail to properly maintain the cryptographic properties necessary for signature verification. This vulnerability falls under the category of cryptographic implementation errors that are commonly classified as CWE-310 in the Common Weakness Enumeration system, representing weaknesses in cryptographic implementations that can lead to serious security consequences. The flaw specifically affects the signature generation process where the mathematical relationships between the private key components and the signature values are not correctly maintained, allowing for the construction of valid signatures through alternative mathematical pathways.
The operational impact of this vulnerability is severe as it enables attackers to create fraudulent digital signatures that will be accepted as legitimate by systems relying on the affected LibTomCrypt library. This compromises the authenticity verification mechanisms that are essential for secure communications, software distribution, and digital authentication processes. Systems using vulnerable versions of LibTomCrypt may be susceptible to man-in-the-middle attacks, software tampering, and authentication bypass scenarios where malicious actors can impersonate legitimate entities. The vulnerability is particularly dangerous because it operates at the cryptographic algorithm level, affecting all applications that depend on the library for signature generation and verification.
Mitigation strategies for CVE-2005-1600 require immediate upgrading to LibTomCrypt version 1.0.3 or later, which contains the necessary corrections to the El Gamal signature implementation. Organizations should conduct thorough inventory assessments to identify all systems utilizing vulnerable library versions and implement comprehensive patch management processes. Additionally, security teams should consider performing cryptographic key rotation for any systems that may have been exposed to signature forgery attacks, particularly in environments where the affected library was used for critical authentication or integrity verification processes. The remediation process should align with industry best practices for cryptographic library management and adhere to frameworks such as those recommended by NIST SP 800-57 for cryptographic key management and security assessment protocols.