CVE-2018-14933 in NVRmini
Summary
by MITRE
upgrade_handle.php on NUUO NVRmini devices allows Remote Command Execution via shell metacharacters in the uploaddir parameter for a writeuploaddir command.
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Analysis
by VulDB Data Team • 12/19/2024
The vulnerability identified as CVE-2018-14933 resides within the upgrade_handle.php script of NUUO NVRmini network video recorder devices, representing a critical remote command execution flaw that fundamentally compromises the device's security posture. This vulnerability specifically affects the writeuploaddir command functionality where the uploaddir parameter fails to properly sanitize user input, creating an exploitable condition that allows attackers to inject shell metacharacters directly into the system's command processing pipeline. The flaw stems from inadequate input validation and improper parameter handling within the device's firmware implementation, enabling malicious actors to execute arbitrary commands with the privileges of the web server process.
The technical exploitation of this vulnerability occurs through the manipulation of the uploaddir parameter in the writeuploaddir command, where attacker-controlled input containing shell metacharacters such as semicolons, ampersands, or backticks can be processed without proper sanitization. When the device processes these malicious inputs through the upgrade_handle.php script, the system executes the embedded commands directly within the operating system context, bypassing normal access controls and authentication mechanisms. This type of vulnerability falls under CWE-77 which specifically addresses "Improper Neutralization of Special Elements used in a Command ('Command Injection')", and aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter. The vulnerability's impact extends beyond simple command execution as it provides attackers with the ability to manipulate the device's file system, potentially leading to persistent access, data exfiltration, or further network compromise.
The operational implications of this vulnerability are severe for organizations relying on NUUO NVRmini devices for surveillance and security monitoring. Remote attackers can leverage this flaw to gain full control over the affected devices, potentially allowing them to modify video recordings, disable security features, or use the compromised devices as entry points for broader network attacks. The vulnerability affects the device's administrative interface and upgrade functionality, making it particularly dangerous as legitimate administrators might unknowingly trigger the exploit during routine maintenance operations. Organizations using these devices face risks including unauthorized access to sensitive surveillance data, potential data breaches, and the compromise of entire security infrastructures where these devices serve as critical components.
Mitigation strategies for CVE-2018-14933 should prioritize immediate firmware updates from NUUO to address the input validation deficiencies in upgrade_handle.php. Network segmentation and access control measures should be implemented to limit exposure of these devices to untrusted networks, while monitoring systems should be deployed to detect unusual command execution patterns or unauthorized access attempts. Security teams should also implement network-based intrusion detection systems that can identify suspicious payload patterns associated with command injection attacks, and conduct regular vulnerability assessments to identify similar input validation issues in other network components. The remediation process should include disabling unnecessary services, implementing strong authentication mechanisms, and establishing comprehensive logging and monitoring procedures to detect exploitation attempts. Organizations should also consider conducting security awareness training for administrators to prevent accidental exploitation during routine maintenance activities, as the vulnerability can be triggered through legitimate administrative operations if proper input validation is not in place.