CVE-2025-43989 in NR500-EA
Summary
by MITRE • 08/13/2025
The /goform/formJsonAjaxReq POST endpoint of Shenzhen Tuoshi NR500-EA RG500UEAABxCOMSLICv3.4.2731.16.43 devices mishandles the set_timesetting action with the ntpserver0 parameter, which is used in a system command. By setting a username=admin cookie (bypassing normal session checks), an unauthenticated attacker can use that parameter to execute arbitrary OS commands.
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Analysis
by VulDB Data Team • 08/15/2025
The vulnerability identified as CVE-2025-43989 affects Shenzhen Tuoshi NR500-EA RG500UEAABxCOMSLICv3.4.2731.16.43 devices where the /goform/formJsonAjaxReq POST endpoint fails to properly validate the ntpserver0 parameter during the set_timesetting action. This represents a critical command injection flaw that allows unauthenticated remote code execution. The vulnerability stems from improper input sanitization where user-supplied data flows directly into system commands without adequate validation or escaping mechanisms. The device's web interface processes this parameter within a system command context, creating a direct pathway for attackers to inject malicious commands that execute with the privileges of the web server process. The exploitation requires setting a username=admin cookie which bypasses normal session authentication mechanisms, though this bypass is itself a security weakness that compounds the overall risk. This vulnerability aligns with CWE-77 and CWE-94, representing command injection and code injection flaws respectively, both of which are classified as high-risk in the Common Weakness Enumeration catalog. The attack vector operates through the web interface using HTTP POST requests to the specific endpoint, making it accessible over the network without requiring physical access or prior authentication.
The operational impact of this vulnerability is severe as it provides attackers with complete control over the affected device. Once exploited, an attacker can execute arbitrary operating system commands with the privileges of the web server process, which typically runs with elevated permissions on network devices. This allows for full system compromise including data exfiltration, installation of persistent backdoors, modification of network configurations, and potential use as a pivot point for attacking other devices on the network. The vulnerability affects time synchronization functionality specifically, but the command injection occurs at a level that can execute any legitimate system command available to the device. The fact that the vulnerability can be triggered through a simple HTTP POST request with a crafted parameter makes it particularly dangerous as it requires minimal reconnaissance and can be automated. Network security monitoring may not easily detect this attack as it appears to be legitimate administrative functionality, and the command execution occurs at the operating system level rather than through the application layer, making traditional web application firewalls ineffective. The vulnerability is consistent with ATT&CK technique T1059.001 for command and scripting interpreter, and T1078.004 for valid accounts, as it leverages a legitimate administrative interface with compromised credentials to achieve unauthorized access.
Mitigation strategies for CVE-2025-43989 should focus on immediate network segmentation and access control measures. Organizations should implement strict network access controls to limit access to the affected device to only authorized administrative networks and users. The device should be updated with the vendor-provided security patch as soon as it becomes available, though the vulnerability's nature suggests that any patch must thoroughly address the input validation mechanisms for system commands. Network monitoring should be enhanced to detect unusual patterns in the /goform/formJsonAjaxReq endpoint usage, particularly POST requests with suspicious parameter values. The username=admin cookie bypass represents a separate authentication weakness that should be addressed through proper session management and authentication controls. Device administrators should disable unnecessary services and interfaces, and implement network access control lists to restrict access to the device's web interface. Regular security audits should be conducted to identify and remediate similar input validation flaws in other device components. The vulnerability highlights the importance of input validation and output encoding in web applications, particularly when dealing with system-level commands. Organizations should also consider implementing intrusion detection systems that can identify patterns consistent with command injection attacks, and establish incident response procedures specifically for device-level compromise scenarios. Security teams should monitor vendor advisories for updates and consider deploying network-based protections that can block known malicious patterns targeting this specific vulnerability. The remediation process must ensure that all parameters that feed into system commands are properly validated and sanitized according to security best practices, and that the principle of least privilege is applied to web server processes.