CVE-2019-20033 in SV8100
Summary
by MITRE
On Aspire-derived NEC PBXes, including all versions of SV8100 devices, a set of documented, static login credentials may be used to access the DIM interface.
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Analysis
by VulDB Data Team • 07/30/2020
The vulnerability identified as CVE-2019-20033 represents a critical authentication flaw affecting NEC PBX systems based on the Aspire architecture, particularly impacting all SV8100 device variants. This weakness stems from the implementation of hardcoded static credentials within the system's DIM (Device Interface Manager) interface, creating a persistent security risk that undermines the fundamental principle of secure authentication mechanisms. The vulnerability exists at the application layer and specifically targets the administrative access points of enterprise telephony systems, making it particularly dangerous for organizations relying on these communication infrastructures. The static nature of these credentials means they remain unchanged across system deployments and updates, creating a persistent attack surface that adversaries can exploit repeatedly without requiring additional reconnaissance or privilege escalation techniques. This flaw directly violates security best practices outlined in the OWASP Top Ten and aligns with CWE-798, which specifically addresses the use of hardcoded credentials in software systems.
The technical exploitation of this vulnerability occurs through the DIM interface, which serves as a critical management endpoint for configuring and maintaining NEC PBX systems. Attackers can leverage the documented static credentials to gain unauthorized administrative access to the system, potentially enabling them to modify telephony configurations, intercept communications, or establish persistent backdoors within the network infrastructure. The DIM interface typically provides access to system parameters, user management, and configuration settings that control the entire PBX ecosystem, making this vulnerability particularly attractive to threat actors seeking comprehensive system compromise. This access pathway bypasses normal authentication mechanisms and represents a classic case of insecure credential storage, where the system's security posture is fundamentally weakened by hardcoded secrets that cannot be rotated or updated through standard security procedures. The vulnerability's impact extends beyond simple unauthorized access, as it can facilitate lateral movement within networks where PBX systems serve as communication hubs for enterprise infrastructure.
The operational impact of CVE-2019-20033 on affected organizations can be severe and far-reaching, particularly for enterprises that depend on NEC PBX systems for critical communication services. Unauthorized access to the DIM interface enables attackers to modify system configurations, potentially disrupting communication services or creating blind spots in network monitoring. The vulnerability can be exploited by both external attackers and insider threats, as the static credentials are documented and readily available, eliminating the need for sophisticated attack techniques or extended reconnaissance periods. Organizations may experience service degradation or complete communication outages if attackers manipulate system configurations, while the potential for data interception and eavesdropping on voice communications presents significant confidentiality risks. This vulnerability also creates opportunities for attackers to establish persistent access points within the network, potentially enabling them to maintain control over the PBX infrastructure for extended periods. The impact is particularly concerning in regulated environments where telecommunications systems must maintain strict security controls and audit trails.
Mitigation strategies for CVE-2019-20033 require immediate action to address the hardcoded credential issue and implement additional security controls around the affected PBX systems. Organizations should first verify which systems are running vulnerable versions of the Aspire-based PBX software and then implement network segmentation to isolate these devices from critical network segments. The most effective immediate remediation involves disabling or removing access to the DIM interface when not required for maintenance operations, while also implementing network access controls to restrict access to these administrative interfaces to authorized personnel only. System administrators should also consider implementing additional authentication layers or VPN access controls to provide defense-in-depth protection. The vulnerability's classification under CWE-798 emphasizes the need for complete credential removal from source code and implementation of dynamic credential generation or secure credential management systems. Organizations should also conduct comprehensive security assessments of their telephony infrastructure, review access controls, and implement monitoring solutions to detect unauthorized access attempts to these administrative interfaces. This vulnerability demonstrates the critical importance of following the principle of least privilege and implementing secure configuration management practices as outlined in NIST SP 800-125 and other security frameworks.