CVE-2018-21105 in R7800
Summary
by MITRE
NETGEAR R7800 devices before 1.0.2.60 are affected by command injection by an authenticated user.
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Analysis
by VulDB Data Team • 06/02/2024
The vulnerability identified as CVE-2018-21105 affects NETGEAR R7800 wireless routers running firmware versions prior to 1.0.2.60. This represents a critical command injection flaw that allows authenticated users to execute arbitrary commands on the affected devices. The vulnerability stems from inadequate input validation and sanitization within the router's web interface administration functionality, specifically in the handling of user-supplied parameters that are subsequently passed to system commands without proper escaping or filtering mechanisms. The affected device model R7800 is a high-performance dual-band wireless router commonly deployed in enterprise and home networking environments, making this vulnerability particularly concerning given the widespread adoption of these devices.
The technical implementation of this command injection vulnerability occurs through the web-based management interface of the router where authenticated users can manipulate input fields that are directly incorporated into system command execution paths. When a user submits specific malicious input through the web interface, the application fails to properly sanitize or escape the input before passing it to underlying system commands, creating an environment where arbitrary shell commands can be executed with the privileges of the web server process. This flaw falls under the Common Weakness Enumeration category CWE-77 which specifically addresses command injection vulnerabilities, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter. The vulnerability is particularly dangerous because it requires only authentication to the web interface, which is typically accessible to local network users or those who have obtained valid credentials through social engineering or other means.
The operational impact of this vulnerability extends beyond simple unauthorized command execution, as it can enable attackers to gain persistent access to network infrastructure, modify router configurations, redirect traffic, or establish backdoors for future access. An attacker who successfully exploits this vulnerability could potentially compromise the entire network segment served by the affected router, as the device acts as a central point of network control and routing. The exploitation process typically involves crafting malicious input that bypasses authentication checks and then injecting shell commands that can manipulate the router's operating system, potentially leading to complete system compromise. Network administrators who have not updated their firmware versions remain at risk, as the vulnerability exists in the default configuration of devices shipped with older firmware versions.
Mitigation strategies for CVE-2018-21105 primarily focus on firmware updates provided by NETGEAR, specifically version 1.0.2.60 or later, which address the input validation issues and implement proper sanitization of user-supplied data. Organizations should immediately assess their network inventory to identify all affected R7800 devices and schedule firmware updates as a priority. Additional protective measures include implementing network segmentation to limit access to administrative interfaces, enforcing strong authentication mechanisms, disabling unnecessary services, and monitoring network traffic for suspicious command execution patterns. The vulnerability demonstrates the importance of regular firmware maintenance and security auditing of network infrastructure devices, as unpatched authentication bypass vulnerabilities can provide attackers with persistent access to critical network resources. Security teams should also consider implementing intrusion detection systems that can identify potential exploitation attempts targeting known command injection patterns in web applications.