CVE-2008-2780 in Anubis Plugin
Summary
by MITRE
The Anubis (aka Anubis+Ripe160) plugin before 1.3 for encrypt stores the unencrypted file s size in cleartext in the header of the encrypted file, which allows attackers to distinguish between encrypted data and random padding at the end of the encrypted file.
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Analysis
by VulDB Data Team • 11/16/2017
The vulnerability described in CVE-2008-2780 affects the Anubis encryption plugin version 1.2 and earlier, which implements the Anubis+Ripe160 encryption algorithm. This flaw represents a significant cryptographic weakness that undermines the security properties of the encryption system. The issue manifests in the plugin's handling of file headers during the encryption process, where the original file size is stored in plaintext within the encrypted file's header structure. This design decision creates a fundamental information disclosure vulnerability that directly impacts the confidentiality guarantees provided by the encryption mechanism.
The technical flaw stems from the plugin's failure to properly obscure metadata within the encrypted file format. When encrypting files, the Anubis plugin stores the original file size in cleartext within the header section of the encrypted output. This cleartext storage of file size information creates a predictable pattern that attackers can exploit to analyze the encrypted data structure. The vulnerability specifically affects the end-of-file padding analysis, as attackers can identify where the actual encrypted data ends and where random padding begins by examining the stored file size value. This characteristic violates fundamental cryptographic principles that require all metadata within encrypted files to remain confidential and indistinguishable from the encrypted content itself.
From an operational impact perspective, this vulnerability enables attackers to perform statistical analysis and pattern recognition on encrypted files, potentially leading to information leakage about the original content. The ability to distinguish between actual encrypted data and padding creates opportunities for side-channel attacks that could reveal file types, sizes, or even partial content characteristics. This weakness particularly affects scenarios where the encryption plugin is used for sensitive data protection, as it undermines the assumption that encrypted files provide complete confidentiality. The vulnerability also impacts the plugin's resistance to traffic analysis attacks, where adversaries could correlate encrypted file sizes with known file patterns or types, potentially compromising the security of communications or data storage systems that rely on this encryption mechanism.
The vulnerability aligns with CWE-310, which addresses cryptographic weaknesses in data encryption systems, specifically focusing on the improper handling of metadata within encrypted formats. From an ATT&CK framework perspective, this vulnerability maps to techniques involving information gathering and reconnaissance activities, as attackers can use the cleartext file size information to better understand the encrypted data structure and potentially improve their decryption or analysis capabilities. The flaw also relates to privilege escalation and credential access patterns, as it provides attackers with additional information that could be leveraged in more sophisticated attacks against the encryption system. Organizations using this encryption plugin should consider implementing immediate mitigations including upgrading to version 1.3 or later, where the file size information is properly obscured, and conducting thorough security assessments to identify any potential exploitation of this vulnerability in their existing encrypted data repositories.