CVE-2019-4656 in IBM
Summary
by MITRE
IBM MQ and IBM MQ Appliance 7.1, 7.5, 8.0, 9.0 LTS, 9.1 LTS, and 9.1 CD is vulnerable to a denial of service attack that would allow an authenticated user to crash the queue and require a restart due to an error processing error messages. IBM X-Force ID: 170967.
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Analysis
by VulDB Data Team • 04/16/2024
The vulnerability identified as CVE-2019-4656 affects IBM MQ and IBM MQ Appliance across multiple versions including 7.1, 7.5, 8.0, 9.0 LTS, 9.1 LTS, and 9.1 CD. This issue represents a significant denial of service weakness that specifically targets the error message processing functionality within the messaging queue system. The flaw allows authenticated users to exploit a condition that leads to system instability and complete service disruption requiring manual intervention through system restarts. The vulnerability operates at the core messaging infrastructure level where error handling mechanisms fail to properly process certain error conditions, creating a cascading failure that brings the entire queue management system to a halt. This represents a critical operational risk for enterprises relying on IBM MQ for mission-critical messaging processes.
The technical implementation of this vulnerability stems from improper error handling within the message processing subsystem of IBM MQ. When authenticated users send specific malformed or crafted error messages, the system's error processing routines encounter conditions that trigger unexpected behavior in the queue manager's memory management and resource allocation mechanisms. This typically manifests through buffer overflows, memory corruption, or resource exhaustion scenarios that cause the queue manager process to crash or become unresponsive. The vulnerability is particularly concerning because it requires only authenticated access, meaning that legitimate users with appropriate credentials can exploit this weakness without requiring external network access or elevated privileges. The error processing failure occurs during the normal operation of the messaging system when handling error conditions, making detection difficult and potentially allowing attackers to cause sustained disruption.
The operational impact of CVE-2019-4656 extends beyond simple service interruption to encompass significant business continuity risks and operational overhead. Organizations utilizing affected IBM MQ versions face potential downtime that can span from minutes to hours depending on the recovery process required for system restarts and configuration validation. The need for manual intervention creates operational bottlenecks and requires system administrators to respond immediately to restore service availability. This vulnerability directly impacts the availability aspect of the CIA triad and can be categorized under CWE-121 as heap-based buffer overflow or CWE-122 as buffer overflow in stack-based memory. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under the T1499.004 sub-technique for network denial of service, specifically targeting application-level services to create availability disruptions.
Organizations should implement immediate mitigations including applying the relevant IBM security patches and updates released for this vulnerability. Configuration hardening measures such as implementing stricter access controls and monitoring for unusual error message patterns can provide additional defense-in-depth. Network segmentation and limiting authenticated access to essential personnel only can reduce the attack surface. The vulnerability demonstrates the importance of proper error handling practices in enterprise messaging systems and highlights the need for comprehensive security testing of error processing code paths. System monitoring should include detection of abnormal queue manager restart patterns and resource consumption spikes that may indicate exploitation attempts. Regular security assessments of messaging infrastructure components should be conducted to identify similar weaknesses in other system components that may present similar attack vectors. The vulnerability also underscores the necessity of maintaining current security patches and implementing robust incident response procedures for handling authenticated user exploits that target core infrastructure components.