CVE-2015-3167 in PostgreSQL
Summary
by MITRE
contrib/pgcrypto in PostgreSQL before 9.0.20, 9.1.x before 9.1.16, 9.2.x before 9.2.11, 9.3.x before 9.3.7, and 9.4.x before 9.4.2 uses different error responses when an incorrect key is used, which makes it easier for attackers to obtain the key via a brute force attack.
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Analysis
by VulDB Data Team • 11/26/2024
The vulnerability described in CVE-2015-3167 represents a cryptographic weakness in PostgreSQL's pgcrypto module that significantly undermines the security of encrypted data. This issue affects multiple PostgreSQL versions including 9.0.20, 9.1.16, 9.2.11, 9.3.7, and 9.4.2, where the database system exhibits inconsistent error handling behavior when processing cryptographic operations with incorrect keys. The flaw stems from the implementation's failure to provide uniform error responses regardless of whether an incorrect key was used, creating a timing-based side-channel attack vector that exposes information about the cryptographic key structure.
The technical exploitation of this vulnerability occurs through a brute force attack methodology that leverages the differential error responses to distinguish between valid and invalid key attempts. When an incorrect key is provided during decryption operations, PostgreSQL returns error messages that differ from those generated when a valid key is used, allowing attackers to perform statistical analysis and gradually deduce the correct key through repeated attempts. This type of vulnerability falls under CWE-310, which specifically addresses cryptographic weaknesses related to improper error handling and information leakage in cryptographic systems. The issue is particularly concerning because it operates at the protocol level where attackers can observe the system's behavior without requiring direct access to the database or its underlying cryptographic libraries.
From an operational impact perspective, this vulnerability creates significant risk for organizations relying on PostgreSQL's encryption features for data protection. The ability to perform brute force attacks against encrypted data means that sensitive information stored in database fields, encrypted using PostgreSQL's pgcrypto module, becomes vulnerable to unauthorized access. Attackers can systematically test potential keys and use the varying error responses to identify correct keys much more efficiently than random guessing would allow. This vulnerability aligns with ATT&CK technique T1211, which covers the exploitation of cryptographic weaknesses to gain unauthorized access to protected data, and demonstrates how seemingly minor implementation flaws can create substantial security risks in database systems.
Organizations should immediately implement mitigation strategies including updating to the patched versions of PostgreSQL that address this specific vulnerability, as well as implementing additional security controls such as connection throttling and monitoring for unusual authentication patterns. The recommended approach involves upgrading to PostgreSQL versions 9.0.20, 9.1.16, 9.2.11, 9.3.7, and 9.4.2 or later, which contain the necessary cryptographic error handling improvements. Additionally, system administrators should consider implementing key rotation policies for encrypted data and strengthening overall database security through network segmentation, access controls, and regular security audits to prevent exploitation of similar timing-based side-channel vulnerabilities that could exist in other cryptographic implementations.