CVE-2019-20025 in SV9100
Summary
by MITRE
Certain builds of NEC SV9100 software could allow an unauthenticated, remote attacker to log into a device running an affected release with a hardcoded username and password, aka a Static Credential Vulnerability. The vulnerability is due to an undocumented user account with manufacturer privilege level. An attacker could exploit this vulnerability by using this account to remotely log into an affected device. A successful exploit could allow the attacker to log into the device with manufacturer level access. This vulnerability affects SV9100 PBXes that are running software release 6.0 or higher. This vulnerability does not affect SV9100 software releases prior to 6.0.
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Analysis
by VulDB Data Team • 07/30/2020
The CVE-2019-20025 vulnerability represents a critical static credential flaw in NEC SV9100 PBX systems, fundamentally undermining the security posture of affected deployments. This vulnerability manifests as a hardcoded authentication mechanism that persists across multiple software releases, specifically impacting versions 6.0 and higher of the SV9100 software suite. The flaw exists in the form of an undocumented administrative account that contains a static username and password combination, creating an inherent backdoor that bypasses normal authentication procedures. Such a design decision violates fundamental security principles and creates a persistent attack vector that remains active regardless of network configuration changes or standard security controls. The vulnerability directly maps to CWE-798, which specifically addresses the use of hardcoded credentials in software applications, representing one of the most severe categories of security flaws due to its inherent persistence and the elevated privileges it provides.
The technical exploitation of this vulnerability requires minimal effort from threat actors, as the hardcoded credentials are readily available through public disclosure channels and security research. An unauthenticated remote attacker can simply connect to the affected device using the predetermined credentials, bypassing all standard authentication mechanisms and gaining immediate administrative access to the PBX system. This access level provides full control over the device's configuration, call routing, user management, and potentially sensitive telephony data. The vulnerability's impact extends beyond simple unauthorized access, as the attacker can modify system configurations, create new user accounts, and potentially intercept or manipulate voice communications. The fact that this vulnerability only affects software releases 6.0 and higher suggests a regression or deliberate introduction of the flaw during software development, indicating a potential security oversight in the release process. Network-based attacks can occur without requiring physical access or prior knowledge of legitimate user credentials, making this vulnerability particularly dangerous in environments where PBX systems are exposed to external networks.
The operational impact of CVE-2019-20025 extends far beyond immediate unauthorized access, creating cascading security risks for organizations relying on affected NEC SV9100 systems. Once an attacker gains manufacturer-level access, they can manipulate the PBX to redirect calls, monitor communications, or even disable critical telephony services, potentially causing significant business disruption. The vulnerability's persistence across system reboots and configuration changes means that even if network security measures are implemented, the hardcoded credentials remain viable attack vectors. Organizations may experience unauthorized data access, potential eavesdropping on sensitive communications, and the ability to modify critical telephony infrastructure settings. The vulnerability also creates a significant challenge for incident response teams, as the presence of hardcoded credentials can complicate forensic analysis and make it difficult to establish clear attack timelines. This flaw essentially provides threat actors with an undetectable backdoor that can be used for long-term persistence within the network environment.
Mitigation strategies for CVE-2019-20025 require immediate action to address the hardcoded credential issue and implement additional protective measures. Organizations must first identify all affected devices and apply the manufacturer-provided patches or firmware updates that address this vulnerability. In cases where patching is not immediately possible, network segmentation should be implemented to isolate affected PBX systems from critical network segments, particularly limiting direct internet access to these devices. Network access control lists should be configured to restrict access to PBX management interfaces to trusted IP addresses only, and all unnecessary services should be disabled. Security monitoring should be enhanced to detect unusual login patterns or access attempts to the affected systems, as these hardcoded credentials may be detected by network intrusion detection systems. Additionally, organizations should implement comprehensive vulnerability management processes that include regular security assessments of all telephony infrastructure, ensuring that such static credential flaws are identified and remediated before they can be exploited. The remediation process should also include a review of all vendor-provided accounts and credentials to ensure that no other hardcoded authentication mechanisms exist within the system, aligning with ATT&CK framework techniques that address credential access and persistence.