CVE-2012-0193 in WebSphere
Summary
by MITRE
IBM WebSphere Application Server (WAS) 6.0 through 6.0.2.43, 6.1 before 6.1.0.43, 7.0 before 7.0.0.23, and 8.0 before 8.0.0.3 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.
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Analysis
by VulDB Data Team • 01/05/2025
IBM WebSphere Application Server versions 6.0 through 6.0.2.43, 6.1 before 6.1.0.43, 7.0 before 7.0.0.23, and 8.0 before 8.0.0.3 contain a vulnerability in their hash table implementation that enables predictable hash collision attacks. This vulnerability falls under the category of CWE-327, which deals with the use of a broken or weak cryptographic hash function, specifically manifesting as a hash collision vulnerability in the parameter processing mechanism. The flaw occurs during the handling of form parameters where the application server computes hash values without proper collision resistance measures, allowing malicious actors to craft specific parameter sets that will consistently hash to the same value.
The technical implementation of this vulnerability stems from the use of an insecure hash function within the WebSphere parameter parsing logic. When form parameters are processed, the server calculates hash values to store and retrieve these parameters efficiently. However, the hash function used does not adequately resist collision attacks, making it possible for an attacker to construct parameter names that will map to identical hash buckets. This creates a scenario where the hash table degenerates into a linked list structure, causing the time complexity for hash operations to increase from O(1) to O(n) where n represents the number of colliding elements. The operational impact is severe as this vulnerability enables a remote attacker to perform a denial of service attack by sending a carefully constructed request containing numerous parameters designed to trigger hash collisions.
The attack vector requires only a network connection to the vulnerable WebSphere server and does not require authentication or special privileges. An attacker can craft HTTP requests with specially designed parameter names that will cause the hash table to experience maximum collision rates, leading to excessive CPU consumption and system resource exhaustion. This vulnerability directly maps to the ATT&CK technique T1499.004, which describes the use of resource exhaustion attacks to cause denial of service conditions. The impact extends beyond simple service disruption as the CPU consumption can escalate to 100% utilization, effectively making the application server unavailable to legitimate users while consuming significant computational resources.
Organizations running affected WebSphere versions should immediately implement mitigations including applying the relevant IBM security patches and updates that address the hash collision vulnerability. Additionally, administrators should consider implementing rate limiting mechanisms, parameter validation, and input sanitization to reduce the impact of such attacks. The recommended approach involves upgrading to patched versions of IBM WebSphere Application Server where the hash function has been strengthened to resist collision attacks. Security teams should also monitor network traffic for unusual patterns of parameter submissions that might indicate attempted exploitation. This vulnerability demonstrates the critical importance of cryptographic robustness in web application frameworks and highlights the need for thorough security testing of core infrastructure components. The issue represents a fundamental weakness in the hash table implementation that could potentially affect other applications using similar hash-based data structures for parameter processing.