CVE-2017-7922 in ePMP
Summary
by MITRE
An Improper Privilege Management issue was discovered in Cambium Networks ePMP. The privileges for SNMP community strings are not properly restricted, which may allow an attacker to gain access to sensitive information and possibly allow for configuration changes.
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Analysis
by VulDB Data Team • 10/19/2019
The vulnerability identified as CVE-2017-7922 represents a critical improper privilege management flaw within Cambium Networks ePMP systems that fundamentally undermines the security posture of network infrastructure devices. This issue specifically targets the handling of SNMP community strings, which serve as the primary authentication mechanism for Simple Network Management Protocol communications. The flaw exists in how the system manages and enforces access controls for these community strings, creating a pathway for unauthorized actors to bypass normal security boundaries and gain elevated privileges. The vulnerability stems from inadequate validation and restriction mechanisms that should normally prevent unauthorized access to sensitive management functions through SNMP protocols.
The technical implementation of this flaw allows attackers to exploit weak privilege controls by leveraging improperly configured SNMP community strings that may contain default or predictable values. When SNMP community strings lack proper access restriction, they essentially function as weak authentication tokens that can be easily discovered or brute-forced by malicious actors. This weakness enables adversaries to perform unauthorized read and write operations against network devices, potentially accessing sensitive configuration data, operational parameters, and system information that should remain protected. The vulnerability specifically affects the ePMP platform's handling of community string permissions, where access controls are not properly enforced, creating a direct attack vector for privilege escalation and unauthorized management access.
The operational impact of CVE-2017-7922 extends far beyond simple information disclosure, as it provides attackers with the capability to perform configuration changes that can severely compromise network security and availability. An attacker who successfully exploits this vulnerability could modify network settings, disable security features, install malicious firmware, or redirect network traffic to facilitate further attacks. The ability to make configuration changes through improperly managed SNMP access creates a persistent threat vector that can be leveraged for long-term network compromise. Network administrators may remain unaware of unauthorized modifications, as the changes could be subtle and blend into normal network operations, making detection particularly challenging.
Organizations utilizing Cambium Networks ePMP systems face significant risk from this vulnerability, as it directly violates fundamental security principles of least privilege and proper access control enforcement. The flaw aligns with CWE-250, which addresses improper privilege management, and represents a clear violation of the principle that network management functions should be protected by strong authentication and authorization controls. From an attack perspective, this vulnerability maps to multiple ATT&CK techniques including privilege escalation and defense evasion, as attackers can leverage the weak SNMP controls to establish persistent access and hide their activities. The vulnerability also demonstrates poor adherence to security best practices for network device management, where default credentials and weak access controls create easily exploitable attack surfaces.
Mitigation strategies for CVE-2017-7922 should prioritize immediate implementation of proper SNMP community string management, including the removal of default community strings, implementation of strong access controls, and enforcement of privilege separation. Organizations must ensure that SNMP community strings are properly configured with appropriate access levels and that read-write permissions are strictly limited to authorized management systems. Network segmentation and firewall rules should be implemented to restrict SNMP traffic to trusted management stations only. Additionally, regular security audits should verify that SNMP configurations follow security best practices and that no unauthorized community strings exist within the network infrastructure. The vulnerability highlights the critical importance of proper privilege management and access control implementation in network security systems, emphasizing that even seemingly simple configuration elements can create substantial security risks when not properly enforced.