CVE-2020-7842 in Korea D'live AP
Summary
by MITRE • 11/21/2020
Improper Input validation vulnerability exists in Netis Korea D'live AP which could cause arbitrary command injection and execution when the time setting (using ntpServerlp1 parameter) for the users. This affects D'live set-top box AP(WF2429TB) v1.1.10.
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Analysis
by VulDB Data Team • 12/09/2020
The CVE-2020-7842 vulnerability represents a critical improper input validation flaw within the Netis Korea D'live AP firmware version 1.1.10, specifically affecting the WF2429TB set-top box AP device. This vulnerability stems from insufficient validation of user-supplied input parameters, particularly when configuring network time protocol settings through the ntpServerlp1 parameter. The flaw allows authenticated attackers with access to the device's configuration interface to inject and execute arbitrary commands on the underlying system, creating a severe security risk that could be exploited for remote code execution and system compromise.
The technical implementation of this vulnerability occurs within the device's time synchronization functionality where the ntpServerlp1 parameter is processed without adequate sanitization or validation. When users configure the NTP server settings through the web interface, the input value is directly incorporated into system commands without proper escaping or filtering mechanisms. This creates a classic command injection vulnerability that falls under CWE-77, which specifically addresses improper neutralization of special elements used in commands. The flaw exists in the application's input handling logic where user-provided data flows directly into shell execution contexts, bypassing all security controls and validation layers that should normally protect against such attacks.
The operational impact of this vulnerability extends beyond simple command injection, as it provides attackers with full system-level access to the affected device. An attacker could potentially execute arbitrary code with the privileges of the web server process, which typically runs with elevated permissions on embedded devices. This could lead to complete device compromise, allowing for persistent backdoor access, data exfiltration, or use of the device as a pivot point for attacking other systems within the local network. The vulnerability affects not just individual devices but could potentially impact entire networks if multiple devices are running the vulnerable firmware version, creating a significant risk for enterprise and home network environments.
Mitigation strategies for CVE-2020-7842 should include immediate firmware updates from Netis Korea to address the input validation flaw, along with network segmentation and access control measures to limit exposure. Organizations should implement proper network monitoring to detect anomalous command execution patterns and ensure that only authorized personnel have access to device configuration interfaces. The vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, highlighting the need for comprehensive security controls. Additionally, implementing input validation at multiple layers including web application firewalls, network intrusion detection systems, and device-specific security measures would provide defense-in-depth protection against similar vulnerabilities in the future.