CVE-2002-0570 in Linux
Summary
by MITRE
The encrypted loop device in Linux kernel 2.4.10 and earlier does not authenticate the entity that is encrypting data, which allows local users to modify encrypted data without knowing the key.
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Analysis
by VulDB Data Team • 06/07/2018
The vulnerability described in CVE-2002-0570 represents a critical flaw in the Linux kernel's handling of encrypted loop devices that fundamentally undermines the security assumptions of data encryption. This issue affects Linux kernel versions 2.4.10 and earlier, where the encrypted loop device implementation lacks proper authentication mechanisms to verify the identity of entities performing encryption operations. The flaw exists at the kernel level within the loop device subsystem, specifically in how it manages encrypted data storage and retrieval operations. When a user mounts an encrypted loop device, the system should ensure that only authorized entities can modify the encrypted data, but this validation process is completely absent.
The technical nature of this vulnerability stems from the absence of cryptographic authentication within the loop device encryption framework. In normal operation, encrypted loop devices should maintain integrity checks and verify the authenticity of encryption operations through proper key management and authentication protocols. However, the flaw allows local users to manipulate encrypted data through direct manipulation of the underlying storage device without possessing the encryption key. This occurs because the system does not validate that the entity attempting to modify the encrypted data has the proper authorization or knowledge of the encryption key. The vulnerability essentially creates a scenario where any local user can modify encrypted data, effectively bypassing the entire encryption security model.
The operational impact of this vulnerability is severe and multifaceted, particularly for systems relying on encrypted storage for sensitive data protection. Local users can exploit this weakness to modify encrypted files, potentially leading to data corruption, unauthorized data modification, or even complete data compromise. The vulnerability affects systems where encrypted loop devices are used for various purposes including database encryption, file system encryption, or any application that relies on the kernel's loop device encryption capabilities. Attackers could leverage this to inject malicious data into encrypted volumes, modify critical system files, or corrupt data in ways that remain undetected. The local nature of the attack means that any user with access to the system can exploit this vulnerability, making it particularly dangerous in multi-user environments where privilege separation is expected.
This vulnerability aligns with CWE-310, which covers cryptographic weaknesses in authentication and key management systems, specifically addressing the lack of proper authentication mechanisms in cryptographic operations. From an attack perspective, this flaw maps to several techniques described in the MITRE ATT&CK framework, particularly those related to privilege escalation and data manipulation. The vulnerability demonstrates a failure in the principle of least privilege and represents a breakdown in the integrity protection mechanisms that should safeguard encrypted data. Systems administrators and security professionals should note that this vulnerability affects the fundamental security model of encrypted storage systems, making it a critical concern for any organization relying on kernel-level encryption features.
The primary mitigation for this vulnerability involves upgrading to Linux kernel versions 2.4.11 and later, where the encryption authentication mechanisms have been properly implemented. Organizations should also conduct comprehensive assessments of their encrypted storage implementations to identify any systems running vulnerable kernel versions. Additionally, implementing proper access controls and monitoring for unauthorized modifications to encrypted volumes can help detect exploitation attempts. System administrators should consider implementing additional layers of security beyond kernel-level encryption, such as application-level integrity checking and regular security audits of encrypted data environments. The vulnerability underscores the importance of proper cryptographic protocol implementation and the necessity of thorough security testing for all encryption-related components within operating system kernels.