CVE-2017-0935 in EdgeOS
Summary
by MITRE
Ubiquiti Networks EdgeOS version 1.9.1.1 and prior suffer from an Improper Privilege Management vulnerability due to the lack of protection of the file system leading to sensitive information being exposed. An attacker with access to an operator (read-only) account could escalate privileges to admin (root) access in the system.
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Analysis
by VulDB Data Team • 01/15/2020
The vulnerability identified as CVE-2017-0935 represents a critical improper privilege management flaw within Ubiquiti Networks EdgeOS firmware versions 1.9.1.1 and earlier. This weakness stems from insufficient file system protection mechanisms that allow unauthorized access to sensitive system components. The vulnerability specifically affects the privilege escalation process within the EdgeOS operating system, which is commonly deployed on Ubiquiti's networking equipment including routers and switches. The flaw manifests when an attacker possesses an operator account with read-only permissions, which typically should restrict access to system-critical functions and configuration files. However, due to the inadequate privilege controls, this limited access can be exploited to gain full administrative privileges equivalent to root access. The vulnerability directly violates the principle of least privilege and demonstrates a fundamental flaw in the system's access control implementation.
The technical exploitation of this vulnerability occurs through the manipulation of file system permissions and access controls within the EdgeOS environment. Attackers can leverage the operator account's limited access to identify and exploit weaknesses in the privilege management system, particularly focusing on how file system objects are protected and accessed. The flaw allows for unauthorized elevation of privileges by bypassing the normal authentication and authorization mechanisms that should prevent a read-only user from accessing administrative functions. This type of vulnerability falls under the CWE-276 category of improper file permissions, where the system fails to properly enforce access controls on critical system files and directories. The underlying issue typically involves the absence of proper file system security attributes or inadequate implementation of access control lists that should prevent unauthorized privilege escalation.
The operational impact of CVE-2017-0935 extends beyond simple privilege escalation to encompass complete system compromise and potential network infiltration. Once an attacker achieves root access through this vulnerability, they gain unrestricted control over the affected networking equipment, enabling them to modify network configurations, intercept traffic, install malicious software, or create backdoors for persistent access. The vulnerability's implications are particularly severe in enterprise and industrial network environments where Ubiquiti EdgeOS devices serve as critical infrastructure components. Network administrators may unknowingly allow attackers to gain complete control over their network perimeter devices, potentially leading to widespread network compromise, data exfiltration, or denial of service attacks. The attack vector requires only an existing operator account, making it relatively accessible to threat actors who may have obtained legitimate access through other means such as default credentials or weak authentication practices.
Mitigation strategies for CVE-2017-0935 require immediate firmware updates to versions that address the privilege management flaw, specifically targeting EdgeOS versions 1.9.2 and later which contain the necessary security patches. Organizations should implement comprehensive network segmentation to limit access to critical devices and reduce the attack surface available to potential adversaries. Security monitoring should include detection of unauthorized operator account usage and privilege escalation attempts, leveraging network logs and system audit trails to identify suspicious activities. The implementation of strong access control policies including mandatory use of strong authentication, regular credential rotation, and disabling unnecessary accounts helps reduce the likelihood of exploitation. Additionally, organizations should conduct regular security assessments of their network infrastructure to identify and remediate similar privilege management vulnerabilities across their entire network ecosystem. This vulnerability demonstrates the importance of proper access control implementation and the need for continuous security monitoring to detect and respond to privilege escalation attempts that could compromise critical network infrastructure.