CVE-2017-7918 in ePMP
Summary
by MITRE
An Improper Access Control issue was discovered in Cambium Networks ePMP. After a valid user has used SNMP configuration export, an attacker is able to remotely trigger device configuration backups using specific MIBs. These backups lack proper access control and may allow access to sensitive information and possibly allow for configuration changes.
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Analysis
by VulDB Data Team • 10/19/2019
The vulnerability CVE-2017-7918 represents a critical improper access control flaw in Cambium Networks ePMP (extended Point-to-Point Multipoint) wireless networking equipment. This issue stems from inadequate authorization controls within the device's SNMP (Simple Network Management Protocol) implementation, specifically during configuration export operations. The vulnerability exists in the management interface of these wireless access points and base stations that are commonly deployed in wireless broadband networks for last-mile connectivity.
The technical exploitation of this vulnerability occurs through SNMP MIB (Management Information Base) manipulation where a valid user session allows an attacker to remotely trigger device configuration backups by leveraging specific MIB objects. This flaw essentially creates a backdoor mechanism that bypasses normal authentication and authorization protocols. The MIB objects in question are designed for configuration management but are improperly exposed without adequate access controls, allowing unauthorized entities to access sensitive device configuration data. The vulnerability is classified under CWE-284 (Improper Access Control) which specifically addresses weaknesses in authorization mechanisms that permit unauthorized access to resources.
The operational impact of this vulnerability is severe as it enables attackers to extract complete device configuration backups that typically contain sensitive information such as network credentials, encryption keys, device settings, and network topology details. These backups could reveal critical infrastructure information that would allow attackers to plan further attacks or establish persistent access to the network. The vulnerability also potentially allows for configuration changes through the same attack vector, enabling attackers to modify device settings and potentially disrupt network operations or create backdoors for continued access. This represents a significant threat to network security as it could lead to complete device compromise and unauthorized network control.
Organizations using Cambium Networks ePMP equipment should immediately implement mitigations including network segmentation to isolate these devices from untrusted networks, implementing strict SNMP access controls with appropriate authentication mechanisms, and applying firmware updates from Cambium Networks as soon as they become available. The vulnerability aligns with ATT&CK technique T1082 (System Information Discovery) and T1078 (Valid Accounts) as attackers can leverage legitimate user sessions to discover system information and maintain persistent access. Network administrators should also consider implementing network monitoring to detect unusual SNMP traffic patterns and unauthorized configuration backup requests, as this vulnerability could be exploited without detection if proper monitoring is not in place. The issue demonstrates the critical importance of proper access control implementation in network management interfaces and highlights the need for comprehensive security testing of management protocols in enterprise networking equipment.