CVE-2025-29524 in GPON ONU H660WM
Summary
by MITRE • 08/26/2025
Incorrect access control in the component /cgi-bin/system_diagnostic_main.asp of DASAN GPON ONU H660WM H660WMR210825 allows attackers to access sensitive information.
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Analysis
by VulDB Data Team • 08/26/2025
The vulnerability identified as CVE-2025-29524 represents a critical access control flaw within the DASAN GPON ONU H660WM and H660WMR210825 devices. This issue manifests in the /cgi-bin/system_diagnostic_main.asp component where insufficient authorization checks permit unauthorized access to sensitive system information. The affected device operates within the telecommunications infrastructure, specifically serving as a GPON (Gigabit Passive Optical Network) Optical Network Unit that connects end-user devices to the service provider's network. The vulnerability stems from improper validation of user permissions and authentication mechanisms within the web interface, creating a pathway for attackers to bypass normal access controls and gain visibility into confidential operational data.
This access control weakness falls under the CWE-284 category of Improper Access Control, specifically targeting the authorization mechanisms that should protect sensitive system diagnostic information. The vulnerability enables attackers to potentially extract system configuration details, network parameters, device status information, and other operational data that could be leveraged for further attacks. The impacted component serves as a diagnostic interface that typically requires administrative privileges to access, yet the flawed implementation allows unauthenticated or low-privileged users to retrieve information that should remain restricted. This flaw particularly affects the principle of least privilege, where users should only have access to resources necessary for their specific role within the system.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with valuable reconnaissance data that can be used to map the network topology and identify potential attack vectors. The compromised device serves as a critical node in the GPON network infrastructure, and unauthorized access to its diagnostic information could reveal network segmentation details, device firmware versions, and operational parameters that would aid in crafting more sophisticated attacks. The vulnerability affects both the H660WM and H660WMR210825 variants, indicating a widespread issue within the product line that requires immediate attention from network administrators. The attack surface is particularly concerning given that GPON ONUs typically operate in customer premises environments where physical security may be limited, making remote exploitation more feasible.
From an attack perspective, this vulnerability aligns with ATT&CK technique T1082 for system information discovery and T1592 for reconnaissance. The ability to access sensitive system diagnostic information through the web interface represents a significant compromise of the device's security posture and could enable attackers to perform network mapping, identify vulnerable services, and potentially escalate privileges within the network. Mitigation strategies should focus on implementing proper authentication mechanisms, enforcing strict access controls on the affected web component, and ensuring that all administrative interfaces require appropriate authorization before granting access to sensitive information. Network segmentation and monitoring of access attempts to the diagnostic interface should also be implemented to detect and prevent unauthorized access attempts.
The vulnerability highlights the importance of proper input validation and access control implementation in network infrastructure devices, particularly those handling sensitive operational data. Organizations should immediately apply vendor-provided patches or firmware updates to address this issue, while also reviewing their network access controls to ensure that only authorized personnel can access administrative interfaces. The affected devices should be monitored for any signs of unauthorized access attempts, and network administrators should consider implementing additional security controls such as network access control lists and intrusion detection systems to protect against exploitation of this vulnerability. Regular security assessments of network infrastructure components should be conducted to identify and remediate similar access control weaknesses that could compromise the overall security posture of the telecommunications network.