CVE-2017-8840 in Balance
Summary
by MITRE
Debug information disclosure exists on Peplink Balance 305, 380, 580, 710, 1350, and 2500 devices with firmware before fw-b305hw2_380hw6_580hw2_710hw3_1350hw2_2500-7.0.1-build2093. A direct request to cgi-bin/HASync/hasync.cgi?debug=1 shows Master LAN Address, Serial Number, HA Group ID, Virtual IP, and Submitted syncid.
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Analysis
by VulDB Data Team • 06/25/2024
The vulnerability described in CVE-2017-8840 represents a critical information disclosure flaw affecting Peplink Balance series network appliances including models 305, 380, 580, 710, 1350, and 2500. This issue stems from insufficient access controls and improper input validation within the web interface configuration of these devices. The vulnerability specifically manifests through a direct request to the HASync component of the device's web server, where a simple parameter injection allows unauthorized access to sensitive system information. The affected firmware versions prior to fw-b305hw2_380hw6_580hw2_710hw3_1350hw2_2500-7.0.1-build2093 contain a debug endpoint that exposes critical operational details without proper authentication mechanisms. This flaw directly violates security principles of least privilege and information hiding, as it provides attackers with access to configuration data that should remain protected within enterprise network infrastructure.
The technical exploitation of this vulnerability occurs through a straightforward HTTP request manipulation that appends the debug parameter to the hasync.cgi endpoint. When processed by the affected devices, this request returns structured debug information including the Master LAN Address which reveals the primary network interface configuration, the Serial Number that uniquely identifies the device for warranty and support purposes, the HA Group ID indicating high availability configuration parameters, the Virtual IP address used for failover operations, and the Submitted syncid that contains synchronization identifiers for cluster management. This information disclosure creates a comprehensive view of the device's operational environment and configuration state, enabling attackers to understand the network topology and prepare subsequent attacks. The vulnerability maps directly to CWE-200 Information Exposure and represents a classic case of insecure direct object reference where an unauthenticated user can access internal system functions.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attack vectors. Network administrators who rely on these appliances for critical infrastructure protection face significant risks when such debug information becomes publicly accessible. The exposed serial numbers and HA group identifiers can be used for targeted attacks against specific device models, while the Master LAN Address and Virtual IP information provide attackers with precise network mapping details. This vulnerability essentially provides a roadmap for attackers to understand the device's role within a network cluster, identify potential failure points, and plan coordinated attacks against the high availability configuration. The exposure of synchronization identifiers could enable attackers to disrupt cluster operations or manipulate data synchronization processes, potentially leading to service degradation or complete system failure. From an ATT&CK perspective, this vulnerability aligns with techniques such as T1082 System Information Discovery and T1068 Exploitation for Privilege Escalation, as it provides the foundational information needed for more advanced exploitation attempts.
Organizations should implement immediate mitigations including firmware updates to the latest available versions that address this vulnerability, network segmentation to isolate these devices from untrusted networks, and access control restrictions to limit who can reach the affected endpoints. The recommended approach involves disabling or restricting access to the HASync debug interface through firewall rules or web application firewalls, implementing proper authentication mechanisms for all administrative interfaces, and conducting comprehensive network audits to identify any other potentially exposed debug endpoints. Additionally, organizations should establish monitoring procedures to detect unauthorized access attempts to these endpoints and implement regular security assessments to identify similar vulnerabilities in other network infrastructure components. The vulnerability serves as a reminder of the importance of secure configuration management and the need for regular security updates in network infrastructure devices.