CVE-2024-0840 in UCM Series IP PBX
Summary
by MITRE • 04/29/2024
The Grandstream UCM Series IP PBX before firmware version 1.0.20.52 is affected by a parameter injection vulnerability in the HTTP interface. A remote and authenticated attacker can execute arbitrary code by sending a crafted HTTP request. Authentication may be possible using a default user and password. Affected models are the UCM6202, UCM6204, UCM6208, and UCM6510.
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Analysis
by VulDB Data Team • 04/29/2024
The vulnerability identified as CVE-2024-0840 represents a critical parameter injection flaw within the Grandstream UCM Series IP PBX devices, specifically affecting firmware versions prior to 1.0.20.52. This security weakness exists within the HTTP interface of these unified communications devices, which are widely deployed in enterprise environments for voice communication services. The affected models including UCM6202, UCM6204, UCM6208, and UCM6510 form part of Grandstream's business-grade IP PBX solutions that serve as central communication hubs for organizations. The vulnerability stems from insufficient input validation mechanisms that fail to properly sanitize user-supplied parameters before processing them within the system's command execution pathways.
The technical exploitation of this vulnerability occurs through a remote authenticated attack vector where an attacker must first establish valid credentials to access the HTTP interface. While default credentials may provide initial access, the flaw allows for privilege escalation once authenticated, enabling the execution of arbitrary code on the affected devices. This parameter injection vulnerability falls under CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: PowerShell." The flaw likely occurs when user-provided parameters are directly incorporated into system commands or configuration updates without proper sanitization, creating opportunities for attackers to inject malicious payloads that can manipulate the underlying operating system.
The operational impact of this vulnerability extends beyond simple unauthorized access, as successful exploitation can result in complete system compromise and potential network infiltration. Attackers could leverage this vulnerability to install backdoors, modify voice communication configurations, intercept calls, or use the compromised PBX as a pivot point to attack other networked systems. The UCM Series devices typically serve as critical infrastructure components within enterprise networks, making them attractive targets for adversaries seeking persistent access or data exfiltration capabilities. Organizations relying on these systems face potential disruption of business communications, regulatory compliance violations, and increased risk of broader security incidents throughout their network infrastructure.
Mitigation strategies for CVE-2024-0840 should prioritize immediate firmware updates to version 1.0.20.52 or later, which contain patches addressing the parameter injection vulnerability. Network segmentation should be implemented to isolate PBX systems from critical network segments, while strict access controls must be enforced through strong authentication mechanisms including multi-factor authentication. Regular security audits should verify that default credentials have been changed and that only necessary services remain accessible. Organizations should also implement network monitoring solutions capable of detecting anomalous traffic patterns that may indicate exploitation attempts, and establish incident response procedures specifically for communication infrastructure compromises. The vulnerability demonstrates the importance of maintaining current firmware versions and following security best practices for networked communication devices, particularly those handling sensitive business communications.