CVE-2019-20030 in UM8000
Summary
by MITRE
An attacker with knowledge of the modem access number on a NEC UM8000 voicemail system may use SSH tunneling or standard Linux utilities to gain access to the system's LAN port. All versions are affected.
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Analysis
by VulDB Data Team • 07/30/2020
The NEC UM8000 voicemail system represents a critical network infrastructure component that handles voice messaging and communication services within enterprise environments. This vulnerability affects all versions of the device and stems from inadequate authentication mechanisms that allow unauthorized access through the modem access number. The flaw exists at the network perimeter level where the system's security controls fail to properly validate access attempts, creating a pathway for attackers to bypass standard security measures. The vulnerability demonstrates a fundamental weakness in the device's access control implementation that directly impacts the confidentiality and integrity of the communication network it serves.
The technical implementation of this vulnerability exploits the system's reliance on a modem access number as a security control mechanism. When an attacker discovers this number, they can leverage standard Linux utilities and SSH tunneling techniques to establish a connection to the system's LAN port. This method of exploitation demonstrates a classic case of insufficient authentication controls where a simple numeric identifier serves as the primary security barrier. The vulnerability allows attackers to gain access to the internal network segment that the voicemail system operates within, potentially providing them with access to additional network resources and systems that may be connected to the same network infrastructure. The flaw essentially creates a backdoor pathway that bypasses normal network security controls and authentication mechanisms.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential network compromise and data exfiltration capabilities. Attackers who successfully exploit this vulnerability can monitor voicemail communications, potentially access sensitive business information, and gain insights into organizational communication patterns. The vulnerability also enables attackers to potentially escalate their access within the network by using the compromised system as a pivot point to target other network resources. This represents a significant risk to enterprise security as voicemail systems often contain sensitive business communications and personal information. The vulnerability's exploitation requires minimal technical expertise, making it particularly dangerous as it can be leveraged by attackers with basic knowledge of network utilities and SSH protocols.
The security implications of this vulnerability align with common attack patterns documented in the attack tactics and techniques framework, specifically relating to initial access and lateral movement phases. The vulnerability demonstrates characteristics consistent with CWE-287 which addresses improper authentication issues in network services. Organizations should consider implementing network segmentation strategies to limit the potential impact of such vulnerabilities and ensure that network access controls are properly configured to prevent unauthorized access to critical systems. The vulnerability also highlights the importance of regularly reviewing and updating access control mechanisms, particularly those relying on simple numeric identifiers or other easily discoverable authentication methods. Proper implementation of multi-factor authentication and network access control policies would significantly mitigate the risk associated with this vulnerability. Organizations should also conduct regular security assessments to identify and remediate similar authentication weaknesses in their network infrastructure components.