CVE-2017-5254 in ePMP
Summary
by MITRE
In version 3.5 and prior of Cambium Networks ePMP firmware, the non-administrative users 'installer' and 'home' have the capability of changing passwords for other accounts, including admin, after disabling a client-side protection mechanism.
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Analysis
by VulDB Data Team • 12/17/2019
The vulnerability identified as CVE-2017-5254 resides within the Cambium Networks ePMP firmware version 3.5 and earlier, representing a critical authorization flaw that undermines the security posture of network infrastructure devices. This issue affects the authentication and access control mechanisms implemented within the firmware, creating a scenario where users with limited privileges can escalate their access rights through unauthorized password modifications. The affected accounts include both the standard 'installer' and 'home' user roles, which are typically granted restricted permissions but are able to exploit a weakness in the system's security architecture.
The technical exploitation of this vulnerability occurs through the manipulation of client-side protection mechanisms that are designed to prevent unauthorized password changes. When these protective measures are disabled, the 'installer' and 'home' user accounts gain the ability to modify credentials for any account on the system, including the administrative account that holds the highest level of privileges. This represents a fundamental breakdown in the principle of least privilege and role-based access control that should normally prevent such cross-account privilege escalation. The flaw essentially allows an attacker with access to either of these low-privilege accounts to assume administrative control over the device.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables a range of malicious activities that can compromise the entire network infrastructure. Once an attacker gains administrative control through password manipulation, they can modify network configurations, install malicious software, monitor network traffic, and potentially use the compromised device as a pivot point for attacking other systems within the network. The vulnerability is particularly concerning because it allows for privilege escalation without requiring additional attack vectors or exploiting other system weaknesses. This makes it an attractive target for attackers seeking to establish persistent access within network environments.
Security practitioners should recognize this vulnerability as a clear example of inadequate access control implementation and improper privilege management within embedded network devices. The flaw aligns with CWE-284, which addresses improper access control, and demonstrates how client-side protections can be circumvented to enable unauthorized administrative actions. Organizations should implement immediate mitigations including firmware updates to versions that address this vulnerability, along with network segmentation and monitoring to detect unauthorized access attempts. Additionally, the incident highlights the importance of proper security testing and validation of access control mechanisms before deployment in production environments, particularly for critical infrastructure devices that serve as network gateways and management points. The vulnerability also relates to ATT&CK technique T1078 which covers valid accounts and privilege escalation through unauthorized access to administrative credentials.