CVE-2013-7463 in aescrypt gem
Summary
by MITRE
The aescrypt gem 1.0.0 for Ruby does not randomize the CBC IV for use with the AESCrypt.encrypt and AESCrypt.decrypt functions, which allows attackers to defeat cryptographic protection mechanisms via a chosen plaintext attack.
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Analysis
by VulDB Data Team • 12/20/2020
The CVE-2013-7463 vulnerability affects the aescrypt gem version 1.0.0 for ruby applications, representing a critical flaw in cryptographic implementation that undermines the security of encrypted data. This vulnerability specifically targets the AESCrypt.encrypt and AESCrypt.decrypt functions within the gem, where the implementation fails to properly randomize the Cipher Block Chaining initialization vector. The absence of proper IV randomization creates a predictable encryption pattern that can be exploited by malicious actors to compromise the confidentiality of encrypted data. This issue fundamentally violates established cryptographic best practices and security principles that require unique, unpredictable initialization vectors for each encryption operation to prevent pattern recognition and cryptographic attacks.
The technical flaw stems from the gem's failure to implement proper randomization of the CBC IV, which is a critical component in the Cipher Block Chaining mode of operation. In CBC mode, each plaintext block is XORed with the previous ciphertext block before encryption, making the IV crucial for ensuring that identical plaintext blocks produce different ciphertext outputs. When the IV is predictable or reused, attackers can perform chosen plaintext attacks that exploit the deterministic nature of the encryption process. This vulnerability directly maps to CWE-327, which addresses the use of weak cryptographic algorithms and improper implementation of cryptographic functions, specifically targeting the weakness in randomization of initialization vectors. The flaw creates a scenario where an attacker who can influence the plaintext of encrypted data can deduce information about the encryption key or plaintext through careful analysis of the ciphertext patterns.
The operational impact of this vulnerability is severe and far-reaching for any ruby application that relies on the aescrypt gem for data encryption. Applications using this gem for password storage, sensitive data protection, or any form of cryptographic data handling become vulnerable to sophisticated attacks that can reveal encrypted information without requiring the cryptographic key. The vulnerability enables attackers to perform plaintext recovery attacks, potentially compromising user credentials, personal information, financial data, and other sensitive materials. This weakness particularly affects web applications, database encryption systems, and any software that stores encrypted data using the vulnerable gem version. The attack surface extends beyond simple data breaches to include potential identity theft, financial fraud, and regulatory compliance violations that can result in significant financial and reputational damage to affected organizations.
Mitigation strategies for CVE-2013-7463 require immediate action to address the vulnerable gem installation and implement proper cryptographic practices. Organizations should upgrade to a patched version of the aescrypt gem or replace it with a more secure encryption library that properly implements random IV generation for CBC mode operations. The recommended approach includes implementing cryptographic libraries that follow industry standards such as those specified in NIST SP 800-38A for block cipher modes of operation. Security teams should conduct comprehensive audits of all ruby applications using the affected gem to identify and remediate vulnerable code paths. Additionally, implementing proper key management practices, ensuring unique IV generation for each encryption operation, and following the principle of least privilege in cryptographic implementations aligns with ATT&CK framework techniques that address credential access and defense evasion through proper cryptographic controls. Organizations should also consider implementing automated vulnerability scanning and dependency management processes to prevent similar issues from occurring in the future and maintain compliance with security standards such as ISO 27001 and PCI DSS requirements for cryptographic controls.