CVE-2012-0884 in OpenSSL
Summary
by MITRE
The implementation of Cryptographic Message Syntax (CMS) and PKCS #7 in OpenSSL before 0.9.8u and 1.x before 1.0.0h does not properly restrict certain oracle behavior, which makes it easier for context-dependent attackers to decrypt data via a Million Message Attack (MMA) adaptive chosen ciphertext attack.
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Analysis
by VulDB Data Team • 12/23/2024
The vulnerability identified as CVE-2012-0884 represents a critical weakness in OpenSSL's implementation of Cryptographic Message Syntax and PKCS #7 standards that significantly undermines the security of encrypted communications. This flaw exists in OpenSSL versions prior to 0.9.8u and 1.0.0h, affecting a substantial portion of cryptographic implementations that rely on these protocols for secure data transmission. The vulnerability specifically targets the oracle behavior within the CMS and PKCS #7 processing mechanisms, creating exploitable conditions that allow attackers to perform sophisticated decryption attacks.
The technical flaw manifests through improper restriction of oracle behavior during cryptographic operations, where the system provides inconsistent timing or error responses that leak information about the decryption process. This vulnerability enables attackers to execute a Million Message Attack, a sophisticated adaptive chosen ciphertext attack that leverages the leaked oracle information to gradually reconstruct the plaintext of encrypted messages. The attack operates by making numerous carefully crafted decryption requests and observing the system's responses to infer cryptographic key material or plaintext content. This represents a fundamental weakness in the cryptographic implementation's resistance to side-channel analysis and timing-based information leakage.
The operational impact of CVE-2012-0884 is severe and far-reaching, as it allows context-dependent attackers to compromise encrypted communications without requiring direct access to the encryption keys. This vulnerability particularly affects systems using OpenSSL for secure email, web communications, and other encrypted data transmission protocols that rely on CMS and PKCS #7 standards. The Million Message Attack can be executed against various cryptographic implementations, including those used in secure web browsers, email clients, and enterprise communication systems, potentially exposing sensitive data such as personal information, financial records, and confidential business communications. The attack's effectiveness stems from the predictable nature of the oracle responses that reveal information about the internal cryptographic processing, making it particularly dangerous in environments where encrypted data transmission is critical.
Mitigation strategies for CVE-2012-0884 require immediate deployment of updated OpenSSL versions that address the oracle behavior restrictions and implement proper cryptographic protections against adaptive chosen ciphertext attacks. System administrators should prioritize upgrading to OpenSSL 0.9.8u or 1.0.0h and later versions that contain the necessary patches to prevent the leakage of oracle information during cryptographic operations. Additional protective measures include implementing proper cryptographic protocol configurations that minimize information leakage, deploying network monitoring to detect suspicious attack patterns, and ensuring that all systems using OpenSSL are regularly updated to maintain security against evolving threats. This vulnerability highlights the importance of proper cryptographic implementation practices and the necessity of rigorous security testing to prevent side-channel attacks that exploit implementation weaknesses rather than fundamental cryptographic flaws. The issue aligns with CWE-310 and ATT&CK techniques related to cryptographic attacks and information disclosure through side-channel analysis, emphasizing the need for comprehensive security measures that address both implementation and operational aspects of cryptographic systems.