CVE-2014-9687 in eCryptfs
Summary
by MITRE
eCryptfs 104 and earlier uses a default salt to encrypt the mount passphrase, which makes it easier for attackers to obtain user passwords via a brute force attack.
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Analysis
by VulDB Data Team • 05/17/2022
The vulnerability identified as CVE-2014-9687 affects eCryptfs versions 104 and earlier, presenting a significant security weakness in the encryption framework designed to protect user data. This flaw stems from the implementation of a default salt value during the encryption process of mount passphrases, which fundamentally undermines the cryptographic security measures intended to safeguard sensitive information. The use of a predictable default salt creates a deterministic encryption environment where attackers can exploit known parameters to streamline password recovery attempts.
The technical implementation flaw lies in the cryptographic design decision to employ a static default salt value rather than generating unique random salts for each encryption operation. This approach violates fundamental cryptographic principles outlined in standards such as NIST SP 800-132, which emphasizes the importance of unique salts to prevent precomputed attacks and ensure proper password hashing. The vulnerability specifically impacts the passphrase encryption mechanism within eCryptfs, where the default salt value remains consistent across different installations and encryption operations, creating a predictable pattern that adversaries can leverage.
From an operational perspective, this vulnerability significantly increases the attack surface for credential compromise, particularly in environments where eCryptfs is deployed for full disk encryption or file-level encryption. Attackers can perform targeted brute force attacks against the encrypted mount passphrases by utilizing the known default salt value, dramatically reducing the computational complexity required to crack user passwords. This weakness enables offline dictionary attacks and password spraying techniques that would otherwise be computationally prohibitive, making the system vulnerable to automated attack tools and reducing the effective security posture of encrypted data.
The impact extends beyond individual user accounts to potentially compromise entire organizational data repositories when eCryptfs is widely deployed. Security frameworks such as the MITRE ATT&CK methodology classify this vulnerability under credential access techniques, specifically targeting the 'Brute Force' and 'Password Spraying' tactics. The vulnerability creates a persistent security risk that remains active until the underlying software is updated, as the default salt value cannot be changed or randomized without system intervention. Organizations relying on eCryptfs for data protection face increased risk of data breaches and unauthorized access, particularly in scenarios where encryption keys or passphrases are stored in predictable locations.
Mitigation strategies should prioritize immediate software updates to eCryptfs versions that implement randomized salt generation for encryption operations, ensuring that each mount passphrase encryption uses unique cryptographic parameters. System administrators must conduct comprehensive vulnerability assessments to identify affected systems and implement proper key management practices that include regular passphrase rotation and the use of strong, unpredictable salts. Additionally, organizations should consider implementing additional security controls such as account lockout mechanisms, multi-factor authentication, and regular security audits to compensate for the weakened cryptographic security until complete remediation is achieved. The vulnerability demonstrates the critical importance of cryptographic best practices and proper salt implementation in maintaining the integrity of encryption systems.