CVE-2017-0913 in UCRM
Summary
by MITRE
Ubiquiti UCRM versions 2.3.0 to 2.7.7 allow an authenticated user to read arbitrary files in the local file system. Note that by default, the local file system is isolated in a docker container. Successful exploitation requires valid credentials to an account with "Edit" access to "System Customization".
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Analysis
by VulDB Data Team • 02/24/2020
The vulnerability identified as CVE-2017-0913 affects Ubiquiti UCRM software versions ranging from 2.3.0 through 2.7.7, representing a critical directory traversal flaw that enables authenticated users to access arbitrary files within the local file system. This weakness stems from insufficient input validation and improper access controls within the application's file handling mechanisms, creating a path traversal vulnerability that can be exploited by malicious actors with appropriate credentials. The vulnerability specifically targets the system's file access functions without adequate sanitization of user-supplied input parameters, allowing attackers to manipulate file paths and gain unauthorized access to sensitive system files that should remain protected.
The exploitation of this vulnerability requires an attacker to possess valid authentication credentials for an account with "Edit" permissions to "System Customization" functionality, which represents a moderate barrier to entry but still poses significant risk given that such access levels are often granted to trusted administrators or system operators. The default deployment configuration of UCRM utilizes docker containerization, which provides an additional layer of isolation between the application and the host system, yet this isolation does not prevent the exploitation of the directory traversal vulnerability. This security gap demonstrates how containerization alone cannot protect against application-level flaws, particularly when proper input validation and access control mechanisms are missing from the application code itself.
The operational impact of this vulnerability extends beyond simple information disclosure, as the ability to read arbitrary files could potentially expose sensitive configuration data, database credentials, application secrets, or other system artifacts that could be leveraged for further exploitation. Attackers could potentially access system configuration files, application logs, or even database files that contain user credentials or other confidential information. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. This weakness allows attackers to access files and directories that are stored outside the intended directory, potentially leading to unauthorized information disclosure, system compromise, or privilege escalation within the application's operational environment.
The threat landscape for this vulnerability is particularly concerning as it requires only valid user credentials with specific permissions rather than administrative privileges or complex attack chains, making it accessible to insiders or attackers who have obtained such credentials through social engineering, credential theft, or other means. From an attacker's perspective, this vulnerability fits within the ATT&CK framework under the T1083 - File and Directory Discovery tactic, where adversaries seek to identify files and directories on compromised systems. The vulnerability also relates to T1078 - Valid Accounts, as it requires legitimate user credentials to exploit, and T1190 - Exploit Public-Facing Application, since UCRM is typically deployed as a web application accessible to authorized users. Organizations should consider this vulnerability as part of their broader security posture assessment, particularly in environments where privileged accounts are compromised or where the principle of least privilege is not properly enforced. The vulnerability highlights the critical importance of input validation, proper access controls, and secure coding practices in preventing directory traversal attacks.
Mitigation strategies should include immediate patching of affected UCRM versions to the latest available releases, which should contain proper input validation and access control mechanisms to prevent directory traversal exploitation. Organizations should also implement strict access control policies, ensuring that only necessary personnel have "Edit" access to "System Customization" functionality, and should regularly audit user permissions to maintain the principle of least privilege. Network segmentation and monitoring should be implemented to detect unusual file access patterns or attempts to read system files. Additionally, organizations should consider implementing web application firewalls or security monitoring solutions that can detect and block directory traversal attempts. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other applications, and developers should follow secure coding guidelines to prevent similar issues in future implementations. The vulnerability serves as a reminder of the importance of validating all user inputs and implementing proper access controls even within isolated containerized environments, as demonstrated by the fact that despite docker isolation, the vulnerability remained exploitable due to flawed application-level logic.