CVE-2015-4941 in WebSphere MQ Light
Summary
by MITRE
IBM WebSphere MQ Light 1.x before 1.0.2 mishandles abbreviated TLS handshakes, which allows remote attackers to cause a denial of service (MQXR service crash) via unspecified vectors.
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Analysis
by VulDB Data Team • 07/02/2022
IBM WebSphere MQ Light 1.x before 1.0.2 contains a critical vulnerability in its TLS implementation that stems from improper handling of abbreviated TLS handshakes. This flaw exists within the cryptographic protocol stack where the system fails to properly validate or process session resumption requests during TLS connections. The vulnerability manifests when remote attackers exploit the incomplete validation of abbreviated handshake parameters, leading to malformed session state transitions that ultimately crash the MQXR service component responsible for message queuing operations.
The technical implementation of this vulnerability resides in the TLS handshake protocol processing logic where abbreviated handshakes are intended to optimize connection establishment by reusing previously negotiated session parameters. However, the WebSphere MQ Light implementation does not adequately validate the integrity of these abbreviated handshake messages, allowing attackers to inject malformed session identifiers or altered handshake parameters that cause the service to enter an unstable state. This improper state handling triggers an unhandled exception within the MQXR service process, resulting in the complete service crash and subsequent denial of service condition for all connected clients.
The operational impact of this vulnerability extends beyond simple service disruption as it affects the core messaging infrastructure that many enterprise applications depend upon for reliable communication. When the MQXR service crashes, it not only interrupts current message processing but also causes connection timeouts and potential data loss for applications relying on the message queue for transactional integrity. The remote nature of the attack means that unauthorized parties can exploit this vulnerability from any network location without requiring local system access or authentication credentials, making it particularly dangerous in production environments where the service may be exposed to untrusted networks.
This vulnerability aligns with CWE-295 which addresses improper certificate validation and CWE-310 which covers cryptographic issues in session management. From an attacker perspective, this weakness maps to the attack pattern of service disruption through protocol manipulation and can be categorized under the MITRE ATT&CK technique T1499.1 for network denial of service attacks. The vulnerability demonstrates poor input validation and error handling practices in cryptographic protocol implementations, which represents a fundamental security flaw in the software's architecture. Organizations using IBM WebSphere MQ Light 1.x should immediately implement the vendor-provided patch version 1.0.2 or higher to address this vulnerability, while also considering network segmentation and access controls to limit exposure to untrusted networks. Additionally, implementing monitoring solutions to detect abnormal service termination patterns can help identify potential exploitation attempts and provide early warning capabilities for similar protocol-based attacks.