CVE-2018-21101 in R7800
Summary
by MITRE
NETGEAR R7800 devices before 1.0.2.60 are affected by command injection by an authenticated user.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/02/2024
The vulnerability identified as CVE-2018-21101 affects NETGEAR R7800 wireless routers running firmware versions prior to 1.0.2.60. This represents a critical command injection flaw that allows authenticated attackers to execute arbitrary commands on the affected devices. The vulnerability stems from improper input validation within the router's web interface, specifically in parameters handling that are used to construct system commands. Attackers who have gained authentication credentials can exploit this weakness to gain unauthorized access to the underlying operating system of the device.
The technical implementation of this vulnerability resides in the router's web application layer where user-supplied input is directly incorporated into system command execution without proper sanitization or validation. This flaw falls under the Common Weakness Enumeration category CWE-77 which specifically addresses command injection vulnerabilities. The vulnerability exists in the context of authenticated sessions, meaning an attacker must first obtain valid credentials to exploit the issue, typically through credential guessing, social engineering, or prior compromise of administrative accounts. The affected device operates on a Linux-based embedded system where commands are executed through shell interfaces, making the injection attack particularly dangerous as it can escalate privileges and potentially provide full system control.
The operational impact of this vulnerability extends beyond simple unauthorized access to include complete system compromise and potential network infiltration. An authenticated attacker can leverage this command injection to execute arbitrary code with root privileges, potentially leading to persistent backdoors, data exfiltration, or use of the device as a pivot point for attacking other systems within the local network. This vulnerability directly maps to ATT&CK technique T1059 which covers command and scripting interpreter, specifically focusing on the execution of system commands through legitimate interfaces. The device's role as a network gateway makes it an attractive target for attackers seeking to establish persistent access or conduct lateral movement within compromised networks.
Mitigation strategies for this vulnerability require immediate firmware updates to version 1.0.2.60 or later, which properly address the input validation issues. Network administrators should also implement strict access controls, enforce strong authentication mechanisms, and monitor for unusual network activity that might indicate exploitation attempts. Additional defensive measures include network segmentation to limit the potential impact of compromise, regular security audits of network devices, and implementation of intrusion detection systems to monitor for command execution patterns. The vulnerability demonstrates the importance of input validation in web applications and highlights the need for security testing of embedded devices that are often overlooked in traditional security assessments. Organizations should also consider implementing network access control policies that restrict administrative access to critical network infrastructure and maintain up-to-date inventory of all network devices to ensure timely patch deployment.