CVE-2016-2461 in Android
Summary
by MITRE
OpenSSLCipher.java in Conscrypt in Android 6.x before 2016-05-01 mishandles resets of the Additional Authenticated Data (AAD) array, which allows attackers to spoof message authentication via unspecified vectors, aka internal bugs 27324690 and 27696681.
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Analysis
by VulDB Data Team • 11/06/2018
The vulnerability identified as CVE-2016-2461 affects the Conscrypt implementation of OpenSSL within Android 6.0 operating system versions released before May 1, 2016. This security flaw resides in the OpenSSLCipher.java file and specifically targets the handling of Additional Authenticated Data (AAD) array resets during cryptographic operations. The issue stems from improper management of AAD state during cipher operations, creating a critical weakness in the authentication mechanisms that protect data integrity. The vulnerability is categorized under CWE-254 as it involves a weakness in cryptographic implementation where the system fails to properly handle authenticated data structures, leading to potential security breaches.
The technical flaw manifests when the AAD array reset functionality is improperly executed within the Conscrypt cryptographic library, allowing attackers to manipulate the authentication process without detection. During authenticated encryption operations, AAD serves as additional data that is authenticated but not encrypted, providing context for the encrypted payload. When the system fails to properly reset or validate the AAD array state, it creates opportunities for attackers to inject malicious data that bypasses the normal authentication checks. This vulnerability specifically impacts the Galois/Counter Mode (GCM) and other authenticated encryption modes where AAD handling is critical for maintaining data integrity and authenticity. The flaw enables attackers to perform message forgery attacks by manipulating the AAD state during cipher operations, potentially leading to successful authentication bypasses and unauthorized data access.
The operational impact of this vulnerability is significant as it affects the core security mechanisms of Android 6.0 devices, potentially allowing attackers to spoof message authentication without detection. This weakness creates a backdoor for malicious actors to manipulate encrypted communications, undermining the fundamental security assumptions of authenticated encryption. The vulnerability affects various Android applications and services that rely on Conscrypt for secure communications, including secure messaging, financial transactions, and enterprise data protection systems. Attackers can exploit this flaw to perform man-in-the-middle attacks, modify encrypted data in transit, or bypass authentication mechanisms that depend on proper AAD handling. The vulnerability's impact extends beyond individual device security to potentially compromise entire communication channels and data protection frameworks that rely on authenticated encryption standards.
Mitigation strategies for CVE-2016-2461 involve implementing the security patch released by Google on May 1, 2016, which addresses the improper AAD array reset handling in the Conscrypt implementation. Organizations should prioritize updating all Android 6.0 devices to the latest security patches and ensure proper validation of cryptographic operations before deployment. System administrators should implement monitoring solutions to detect potential exploitation attempts and establish secure communication protocols that do not rely solely on the vulnerable Conscrypt implementation. The vulnerability aligns with ATT&CK technique T1552.004 which involves the exploitation of cryptographic libraries, and represents a critical weakness in the application of authenticated encryption standards. Additionally, organizations should conduct security audits of their mobile device management systems to ensure all Android devices are properly patched and that cryptographic implementations are regularly validated against known vulnerabilities. The remediation process should include verification of the patched Conscrypt implementation and validation of AAD handling procedures to prevent similar issues in future deployments.