CVE-2016-5430 in jose-php
Summary
by MITRE
The RSA 1.5 algorithm implementation in the JOSE_JWE class in JWE.php in jose-php before 2.2.1 lacks the Random Filling protection mechanism, which makes it easier for remote attackers to obtain cleartext data via a Million Message Attack (MMA).
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Analysis
by VulDB Data Team • 09/14/2022
The vulnerability identified as CVE-2016-5430 affects the RSA 1.5 encryption implementation within the JOSE_JWE class of the jose-php library version prior to 2.2.1. This flaw resides in the cryptographic protocol handling of JSON Web Encryption objects, specifically impacting the RSA encryption scheme used for key encryption. The issue stems from the absence of proper random padding mechanisms that are essential for secure RSA encryption operations.
The technical flaw manifests through the lack of Random Filling protection in the RSA 1.5 algorithm implementation. This absence creates a critical security weakness that enables attackers to exploit the deterministic nature of RSA 1.5 encryption without proper padding. When the encryption process fails to incorporate sufficient randomness through proper padding mechanisms, it becomes vulnerable to mathematical attacks that can recover plaintext data from encrypted messages. The vulnerability specifically affects the Million Message Attack (MMA) technique, which leverages the predictable patterns in improperly padded RSA encryption to gradually reconstruct the original plaintext through multiple encryption attempts.
The operational impact of this vulnerability is severe as it allows remote attackers to systematically recover cleartext data from encrypted messages without requiring direct access to the private keys. This weakness enables attackers to perform statistical analysis and mathematical computations against multiple encrypted messages to deduce the original plaintext content. The vulnerability affects any application using the jose-php library for JSON Web Encryption operations, potentially compromising sensitive data such as authentication tokens, user credentials, and confidential communications that rely on this encryption mechanism. The attack vector requires only network access to the vulnerable service, making it particularly dangerous in web applications and APIs that utilize JWT tokens.
The security implications extend beyond simple data exposure, as this vulnerability aligns with CWE-327, which addresses the use of weak encryption algorithms and improper implementation of cryptographic primitives. This weakness creates opportunities for attackers to perform advanced cryptographic attacks that would normally be prevented by proper padding mechanisms. The vulnerability also relates to ATT&CK technique T1552.004, which covers unsecured credentials and data exposure through cryptographic weaknesses. Organizations relying on jose-php for security-critical applications face significant risk of data breaches and unauthorized access to sensitive information. The vulnerability demonstrates the critical importance of proper cryptographic implementation and adherence to security best practices in software development.
The recommended mitigation strategy involves upgrading to jose-php version 2.2.1 or later, which includes proper implementation of the Random Filling protection mechanism. Additionally, organizations should consider migrating to more secure encryption algorithms such as RSA-OAEP, which provides better security properties than RSA 1.5. Security teams should conduct comprehensive audits of all applications using the jose-php library to identify and remediate affected systems. Implementing proper cryptographic key management practices and regular security assessments will help prevent similar vulnerabilities from emerging in the future. The fix addresses the core implementation issue by ensuring that all RSA encryption operations include appropriate random padding, making the encryption scheme resistant to the Million Message Attack and similar cryptographic attacks.