CVE-2007-2728 in PHP
Summary
by MITRE
The soap extension in PHP calls php_rand_r with an uninitialized seed variable, which has unknown impact and attack vectors, a related issue to the mcrypt_create_iv issue covered by CVE-2007-2727.
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Analysis
by VulDB Data Team • 08/17/2024
The vulnerability described in CVE-2007-2728 affects the soap extension in PHP where the php_rand_r function is called with an uninitialized seed variable. This represents a significant cryptographic weakness that undermines the randomness of generated values within the SOAP extension. The issue stems from improper initialization of random number generation mechanisms, creating predictable sequences that can be exploited by malicious actors. The vulnerability is particularly concerning because it affects the core functionality of PHP's SOAP implementation, which is widely used for web services communication across numerous applications and platforms. When php_rand_r is invoked without proper seed initialization, the underlying random number generator produces deterministic outputs that can be reverse-engineered or predicted by attackers. This weakness directly impacts the security of cryptographic operations that rely on random values for key generation, nonce creation, and session management within SOAP-based web services. The uninitialized seed variable creates a predictable entropy source that reduces the cryptographic strength of the random number generation process to near zero, making it trivial for attackers to compromise the security of applications that depend on this functionality.
The technical flaw manifests in how the SOAP extension interfaces with PHP's random number generation capabilities through the php_rand_r function call. This function requires proper seed initialization to ensure cryptographic randomness, but the SOAP extension fails to provide this initialization, leading to the use of whatever garbage values happen to exist in memory at the time of function invocation. The uninitialized seed creates a deterministic pattern that can be exploited through statistical analysis or by observing multiple outputs to reverse-engineer the seed value. This vulnerability operates at the fundamental level of cryptographic security implementation within PHP's extension architecture, where the lack of proper seed handling creates a persistent weakness that can be leveraged across multiple attack scenarios. The flaw represents a failure in secure coding practices and demonstrates the critical importance of proper initialization of cryptographic primitives in server-side applications. The impact extends beyond simple randomness issues as it can compromise session tokens, encryption keys, and other security-critical values that rely on unpredictable random generation.
The operational impact of this vulnerability is substantial as it affects the security posture of any PHP application that utilizes the SOAP extension for web services communication. Attackers can exploit this weakness to predict random values used in security contexts, potentially leading to session hijacking, credential compromise, and unauthorized access to protected resources. The vulnerability creates opportunities for man-in-the-middle attacks where attackers can predict or reproduce random values used in authentication protocols, making it easier to impersonate legitimate users or systems. The related nature of this issue to CVE-2007-2727, which covers mcrypt_create_iv problems, indicates a broader pattern of uninitialized random number generation across PHP's cryptographic extension libraries. This suggests that applications using multiple cryptographic functions within PHP may be simultaneously vulnerable to similar weaknesses, amplifying the overall risk. Organizations implementing SOAP-based web services in PHP environments face increased exposure to sophisticated attacks that can exploit this randomness weakness to bypass security controls and gain unauthorized access to sensitive data and services.
Mitigation strategies for CVE-2007-2728 require immediate patching of affected PHP installations and careful review of all SOAP extension usage within applications. System administrators should prioritize updating PHP versions to include fixes for this vulnerability, as the issue affects core cryptographic functionality that is fundamental to secure web services operation. The recommended approach includes implementing proper seed initialization for random number generation functions and ensuring that all cryptographic operations within SOAP extensions use properly initialized random sources. Organizations should also consider implementing additional security controls such as input validation, secure session management, and monitoring for unusual patterns in random value generation. The vulnerability highlights the importance of adhering to secure coding practices and proper initialization of cryptographic primitives as outlined in industry standards such as those referenced in CWE-330, which addresses insufficient entropy in random number generation. Security teams should conduct comprehensive vulnerability assessments to identify all applications and services that utilize the affected SOAP extension and ensure proper remediation across the entire infrastructure. Regular security audits and code reviews should be implemented to prevent similar issues in future development cycles, emphasizing the critical need for proper initialization of cryptographic functions in all server-side applications.