CVE-2021-20173 in Nighthawk R6700
Summary
by MITRE • 12/31/2021
Netgear Nighthawk R6700 version 1.0.4.120 contains a command injection vulnerability in update functionality of the device. By triggering a system update check via the SOAP interface, the device is susceptible to command injection via preconfigured values.
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Analysis
by VulDB Data Team • 01/05/2022
The vulnerability identified as CVE-2021-20173 affects Netgear Nighthawk R6700 routers running firmware version 1.0.4.120 and potentially other affected models within the Nighthawk series. This issue represents a critical security flaw that exposes the device to remote command execution capabilities through its update functionality. The vulnerability specifically manifests when the device processes system update checks initiated via the SOAP interface, creating an attack vector that allows malicious actors to inject arbitrary commands into the device's operating system. The flaw stems from insufficient input validation and sanitization within the update processing pipeline, where user-supplied parameters are directly incorporated into system commands without proper security controls.
The technical implementation of this vulnerability falls under the CWE-77 category, which specifically addresses command injection flaws in software systems. This classification indicates that the device's update mechanism fails to properly sanitize or validate input parameters received through the SOAP interface, allowing attackers to inject malicious commands that execute with the privileges of the device's system processes. The attack surface is particularly concerning because it leverages the legitimate update functionality that users typically expect to be secure, making the exploitation more likely to succeed as the device naturally processes these update requests. The vulnerability demonstrates poor input validation practices where preconfigured values are not properly escaped or filtered before being passed to system commands, creating a direct path for arbitrary code execution.
From an operational impact perspective, this vulnerability presents a severe risk to network security and device integrity. An attacker who successfully exploits this command injection flaw can execute arbitrary commands on the affected router, potentially gaining full administrative control over the device. The implications extend beyond the individual device, as compromised routers can serve as entry points for broader network infiltration, allowing attackers to establish persistent access, monitor network traffic, or redirect traffic through malicious proxies. The attack can be performed remotely without requiring physical access to the device, making it particularly dangerous in enterprise and residential network environments where such devices are commonly deployed. The vulnerability also affects the device's ability to maintain security through its update mechanism, as attackers can manipulate the update process to install malicious firmware or disable security features.
The mitigation strategies for CVE-2021-20173 should prioritize immediate firmware updates from Netgear, as the vendor has likely released patches addressing this specific vulnerability. Network administrators should also implement network segmentation and access controls to limit exposure of affected devices to untrusted networks. Additional protective measures include monitoring network traffic for suspicious SOAP requests and implementing intrusion detection systems that can identify command injection attempts. The vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, as it allows adversaries to execute system commands through the device's legitimate interfaces. Organizations should also consider disabling unnecessary SOAP interfaces when not required for device management, as this reduces the attack surface. Regular security assessments of network infrastructure should include verification of device firmware versions and patch compliance to prevent exploitation of similar vulnerabilities in the update functionality of network devices.