CVE-2019-25239 in GPON EPON OLT Platform
Summary
by MITRE • 12/24/2025
V-SOL GPON/EPON OLT Platform 2.03 contains an unauthenticated information disclosure vulnerability that allows attackers to download configuration files via direct object reference. Attackers can retrieve sensitive configuration data by sending HTTP GET requests to the usrcfg.conf endpoint, potentially enabling authentication bypass and system access.
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Analysis
by VulDB Data Team • 12/25/2025
The vulnerability identified as CVE-2019-25239 affects the V-SOL GPON/EPON OLT Platform version 2.03, representing a critical information disclosure flaw that undermines the security posture of telecommunications infrastructure. This vulnerability manifests through an improper access control mechanism that permits unauthenticated users to directly reference and download sensitive configuration files from the system. The affected platform operates within the telecommunications sector, specifically managing passive optical network infrastructure that connects service providers to end-user devices, making it a prime target for attackers seeking to compromise network operations and customer data.
The technical flaw resides in the web application's handling of direct object references within the usrcfg.conf endpoint, which lacks proper authentication and authorization checks. When attackers send HTTP GET requests to this specific endpoint, they can bypass the normal authentication mechanisms and directly access configuration files that contain sensitive operational data including user credentials, network settings, and system parameters. This represents a classic case of insecure direct object reference vulnerability, categorized under CWE-284, where the application provides direct access to objects based on user-supplied input without proper access control validation. The vulnerability exists because the system fails to verify whether the requesting entity has legitimate authorization to access the requested configuration file, creating an attack surface that allows arbitrary data extraction.
The operational impact of this vulnerability extends beyond simple information disclosure, as the retrieved configuration files often contain credentials and system parameters that can enable attackers to establish persistent access to the network infrastructure. Attackers can leverage the exposed configuration data to perform authentication bypass attacks, potentially gaining administrative privileges within the OLT platform and executing further malicious activities. The compromised system may allow attackers to manipulate network configurations, redirect traffic, or establish backdoor access points that persist across system reboots. This vulnerability particularly affects service providers who rely on GPON/EPON infrastructure for delivering internet, voice, and video services to residential and business customers, potentially exposing thousands of endpoints to unauthorized access and data breaches.
Security professionals should implement multiple layers of mitigation to address this vulnerability, beginning with immediate patching of affected systems to remediate the insecure direct object reference implementation. Network segmentation and firewall rules should be configured to restrict access to the usrcfg.conf endpoint from unauthorized networks, while implementing strong authentication mechanisms for all administrative interfaces. The principle of least privilege should be enforced by ensuring that only authorized personnel can access sensitive configuration data through properly authenticated channels. Organizations should also deploy intrusion detection systems to monitor for suspicious HTTP GET requests targeting the vulnerable endpoint, and conduct regular security assessments to identify similar vulnerabilities in other network infrastructure components. This vulnerability aligns with ATT&CK technique T1213.002 for Credential Access, specifically focusing on the extraction of credentials from network devices, and demonstrates the importance of proper access control implementation in network infrastructure management systems.