CVE-2020-3932 in VigorAP910C
Summary
by MITRE
A vulnerable SNMP in Draytek VigorAP910C cannot be disabled, which may cause information leakage.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 05/27/2024
The CVE-2020-3932 vulnerability affects the Draytek VigorAP910C wireless access point device where the Simple Network Management Protocol implementation cannot be disabled, creating a persistent security risk. This issue represents a critical configuration flaw in the device's network management infrastructure that allows unauthorized access to sensitive operational data through the SNMP protocol. The vulnerability stems from the device's hardcoded SNMP configuration that remains active regardless of administrative settings, enabling potential attackers to extract network information, device configurations, and operational metrics without proper authentication.
This vulnerability operates at the network infrastructure level and constitutes a design flaw in the device's security architecture. The SNMP service runs continuously on the device with default credentials and accessible management interfaces that cannot be properly secured through standard configuration methods. The technical implementation fails to provide administrators with the ability to completely disable the SNMP protocol, which violates fundamental security principles of least privilege and defense in depth. According to CWE-1004, this represents a security weakness where security-relevant features cannot be properly disabled or configured, creating persistent attack vectors that persist across device reboots and configuration changes.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass potential network reconnaissance and subsequent compromise scenarios. Attackers can leverage the persistent SNMP service to gather detailed network topology information, device firmware versions, and configuration parameters that provide valuable intelligence for planning more sophisticated attacks. The vulnerability creates a persistent backdoor that remains active even when administrators believe they have secured the device, making it particularly dangerous for enterprise environments where network segmentation and access controls are critical. This aligns with ATT&CK technique T1082 which involves discovering information about the system environment through reconnaissance activities.
The security implications of CVE-2020-3932 are significant for organizations relying on Draytek VigorAP910C devices in their wireless infrastructure. The inability to disable SNMP creates a permanent information leakage channel that can be exploited by threat actors to map network topologies, identify vulnerable services, and gather intelligence for lateral movement within the network. Network administrators may not be aware that their devices remain vulnerable even after implementing standard security measures, as the SNMP service operates independently of normal configuration controls. This vulnerability particularly impacts organizations with strict compliance requirements where unauthorized information disclosure can result in regulatory violations and security breaches.
Organizations should implement immediate mitigations including network segmentation to isolate affected devices from critical network segments, deploying network access controls to restrict SNMP traffic to authorized management systems only, and monitoring for unauthorized SNMP activity on the network. Device firmware updates from Draytek should be prioritized to address the underlying implementation flaw, while administrators should consider implementing network intrusion detection systems to monitor for SNMP-based reconnaissance activities. The vulnerability highlights the importance of proper security configuration management and the need for comprehensive device lifecycle management practices to prevent similar issues in other network infrastructure components. Additionally, organizations should conduct thorough inventory assessments to identify all affected devices and implement continuous monitoring to detect potential exploitation attempts.