CVE-2008-6910 in Services
Summary
by MITRE
Services 5.x before 5.x-0.92 and 6.x before 6.x-0.13, a module for Drupal, does not use timeouts for signed requests, which allows remote attackers to impersonate other users and gain privileges via a replay attack that sends the same request.
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Analysis
by VulDB Data Team • 11/20/2018
The vulnerability identified as CVE-2008-6910 affects the Services module for Drupal platforms, specifically versions 5.x prior to 5.x-0.92 and 6.x prior to 6.x-0.13. This security flaw resides within the module's implementation of signed request mechanisms that are critical for authentication and authorization processes within Drupal-based web applications. The Services module enables developers to create RESTful web services that can be consumed by external applications, making it a valuable component for building APIs and integrating third-party systems with Drupal platforms.
The technical core of this vulnerability stems from the absence of timeout mechanisms in the signed request validation process. When Drupal Services module processes authenticated requests, it relies on cryptographic signatures to verify the authenticity and integrity of incoming requests. However, the implementation fails to incorporate time-based validation checks that would prevent the reuse of valid signatures beyond their intended window of validity. This design flaw creates a window of opportunity for attackers to capture legitimate signed requests and replay them at a later time to impersonate authorized users.
The operational impact of this vulnerability is significant as it allows remote attackers to perform privilege escalation attacks without requiring knowledge of user credentials. Through a replay attack, an attacker can capture a valid signed request that contains sufficient authentication tokens and headers, then resend that identical request at a later time when the system accepts it as legitimate. This capability enables unauthorized access to user accounts and potentially administrative privileges depending on the scope of the captured request. The vulnerability particularly affects systems that rely heavily on the Services module for API authentication and user management functions.
The weakness aligns with CWE-347, which focuses on the lack of proper validation of cryptographic signatures, and represents a classic example of insufficient validation of cryptographic signatures. From an attack perspective, this vulnerability maps to ATT&CK technique T1566.002 which involves credential access through the exploitation of vulnerabilities in authentication systems. The absence of timeout mechanisms creates a persistent security gap that can be exploited across multiple sessions and user contexts, making it particularly dangerous for applications that handle sensitive data or administrative functions.
Organizations affected by this vulnerability should immediately upgrade to the patched versions of the Services module as specified in the CVE details. The recommended mitigation strategy involves implementing proper timeout mechanisms for signed requests, typically through the addition of timestamp validation that ensures signatures remain valid only for a predetermined period. Additionally, system administrators should conduct thorough security audits of all Drupal installations to identify and remediate similar vulnerabilities in other modules or custom implementations. Network monitoring should be enhanced to detect unusual patterns of request repetition that might indicate replay attack attempts, and access controls should be reviewed to minimize the potential impact of successful exploitation.