CVE-2020-4766 in MQ Internet Pass-Thru
Summary
by MITRE • 01/23/2021
IBM MQ Internet Pass-Thru 2.1 and 9.2 could allow a remote user to cause a denial of service by sending malformed MQ data requests which would consume all available resources. IBM X-Force ID: 188093.
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Analysis
by VulDB Data Team • 02/19/2021
IBM MQ Internet Pass-Thru version 2.1 and 9.2 contains a vulnerability that enables remote attackers to trigger a denial of service condition through the deliberate submission of malformed MQ data requests. This flaw resides in the processing logic of the internet pass-thru component which fails to properly validate incoming data structures before attempting to handle them. The vulnerability specifically manifests when the system receives crafted malformed requests that cause resource exhaustion, leading to complete service unavailability for legitimate users. The attack vector is entirely remote and does not require authentication, making it particularly dangerous as any external party can exploit this weakness without prior access credentials. The malformed data requests are designed to consume system resources such as memory, CPU cycles, and file descriptors in a manner that exhausts the available capacity, effectively rendering the service inoperable. This vulnerability directly relates to CWE-400 which categorizes unchecked resource consumption as a critical weakness in software systems. The impact extends beyond simple service disruption as it can affect the broader messaging infrastructure that relies on IBM MQ for critical communications. Attackers can leverage this weakness to perform sustained denial of service attacks that may require system restarts to recover fully. The vulnerability affects both the legacy 2.1 version and the newer 9.2 release, indicating that the underlying flaw has persisted across multiple iterations of the software. Organizations using IBM MQ Internet Pass-Thru should consider this a high-priority issue given the remote exploitability and the potential for complete service disruption. The attack pattern aligns with ATT&CK technique T1499 which describes network denial of service attacks targeting system resources. The flaw demonstrates poor input validation practices and inadequate resource management within the pass-thru component, creating an attack surface that can be exploited without significant technical expertise. This vulnerability represents a fundamental failure in the software's defensive mechanisms and highlights the importance of robust resource limiting and input sanitization. The IBM X-Force ID 188093 further validates the severity and specific nature of the exploit path that leads to resource exhaustion. Organizations should implement immediate mitigations including network segmentation, rate limiting, and monitoring for unusual resource consumption patterns. The vulnerability serves as a reminder of the critical importance of validating all external inputs and implementing proper resource management to prevent exploitation of similar weaknesses in enterprise messaging systems.