CVE-2018-14558 in AC7
Summary
by MITRE
An issue was discovered on Tenda AC7 devices with firmware through V15.03.06.44_CN(AC7), AC9 devices with firmware through V15.03.05.19(6318)_CN(AC9), and AC10 devices with firmware through V15.03.06.23_CN(AC10). A command Injection vulnerability allows attackers to execute arbitrary OS commands via a crafted goform/setUsbUnload request. This occurs because the "formsetUsbUnload" function executes a dosystemCmd function with untrusted input.
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Analysis
by VulDB Data Team • 02/05/2025
The vulnerability identified as CVE-2018-14558 represents a critical command injection flaw affecting Tenda wireless routers including AC7 AC9 and AC10 models. This security weakness stems from insufficient input validation within the device's firmware implementation, specifically within the goform/setUsbUnload API endpoint. The vulnerability impacts devices running firmware versions up to and including V15.03.06.44_CN for AC7 AC9 devices and V15.03.05.19(6318)_CN for AC9 models as well as V15.03.06.23_CN for AC10 devices. The flaw resides in how the system processes user-supplied parameters when executing USB unloading operations, creating an avenue for malicious actors to inject and execute arbitrary operating system commands on the affected devices.
The technical exploitation of this vulnerability occurs through the manipulation of the formsetUsbUnload function which directly invokes the dosystemCmd function without proper sanitization of input parameters. This design flaw enables attackers to craft malicious requests that bypass normal input validation mechanisms and execute unauthorized commands on the router's underlying operating system. The vulnerability manifests when an attacker sends a specially crafted HTTP request containing malicious command parameters to the vulnerable API endpoint, allowing complete command execution with the privileges of the router's system process. This type of vulnerability falls under CWE-77 which specifically addresses command injection flaws in software systems.
The operational impact of CVE-2018-14558 extends beyond simple unauthorized command execution, presenting significant security risks for affected networks. Successful exploitation could enable attackers to gain full administrative control over the affected routers, potentially leading to complete network compromise through lateral movement and persistent access. The vulnerability creates a persistent backdoor that could remain undetected for extended periods, allowing threat actors to maintain unauthorized access while potentially using the compromised device as a pivot point for attacking other networked systems. Network administrators face the challenge of securing thousands of potentially compromised devices without user knowledge, as these vulnerabilities often remain dormant until actively exploited. This type of vulnerability aligns with ATT&CK technique T1059.001 which describes command and scripting interpreter usage, and T1021.001 which covers remote services such as SSH and Telnet that could be leveraged through compromised router access.
Mitigation strategies for CVE-2018-14558 require immediate firmware updates from Tenda to address the command injection vulnerability, as well as network segmentation and monitoring to detect potential exploitation attempts. Organizations should implement network access controls to restrict communication with affected devices and deploy intrusion detection systems capable of identifying malicious command injection patterns. Security teams must also conduct comprehensive vulnerability assessments to identify all potentially affected devices within their network infrastructure, as these devices may be used as staging points for more sophisticated attacks. Additionally, network administrators should consider disabling unnecessary services and features on affected routers, particularly USB-related functionality that may not be essential for network operations, thereby reducing the attack surface available to potential attackers.