CVE-2021-29077 in RBW30
Summary
by MITRE • 03/23/2021
Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects RBW30 before 2.6.2.2, RBS40V before 2.6.2.4, RBK852 before 3.2.17.12, RBK853 before 3.2.17.12, RBK854 before 3.2.17.12, RBR850 before 3.2.17.12, RBS850 before 3.2.17.12, RBK752 before 3.2.17.12, RBK753 before 3.2.17.12, RBK753S before 3.2.17.12, RBK754 before 3.2.17.12, RBR750 before 3.2.17.12, and RBS750 before 3.2.17.12.
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Analysis
by VulDB Data Team • 04/04/2021
The vulnerability CVE-2021-29077 represents a critical command injection flaw affecting multiple NETGEAR wireless router models, specifically targeting devices in the RBW30, RBS40V, RBK852, RBK853, RBK854, RBR850, RBS850, RBK752, RBK753, RBK753S, RBK754, RBR750, and RBS750 series. This vulnerability allows unauthenticated attackers to execute arbitrary commands on affected devices, fundamentally compromising their security posture and potentially enabling full system compromise. The flaw stems from insufficient input validation and improper sanitization of user-supplied data within the device's web interface or management protocols, creating an avenue for malicious command execution.
The technical implementation of this vulnerability occurs through the manipulation of input parameters that are directly incorporated into system commands without adequate filtering or escaping mechanisms. Attackers can craft malicious payloads that, when processed by the affected devices, result in arbitrary command execution with the privileges of the web server process. This typically involves exploiting parameters in HTTP requests that are passed directly to shell commands, creating a classic command injection vulnerability as classified under CWE-77. The vulnerability's impact is particularly severe because it requires no authentication, making it accessible to anyone with network access to the affected devices, and the affected firmware versions span multiple generations of NETGEAR's business and consumer-grade wireless routers.
The operational implications of CVE-2021-29077 extend far beyond simple unauthorized access, as successful exploitation can lead to complete system compromise and persistent backdoor access. An attacker who successfully exploits this vulnerability can gain full control over the affected router, potentially enabling them to modify network configurations, redirect traffic, establish persistent access points, or use the device as a launching point for further attacks against the local network. The vulnerability creates a persistent threat vector that can remain undetected for extended periods, as the compromised device may continue to function normally while serving as a covert channel for malicious activities. This aligns with ATT&CK technique T1071.004 for application layer protocol usage and T1059.001 for command and scripting interpreter, demonstrating the multi-faceted attack surface this vulnerability exposes.
Mitigation strategies for CVE-2021-29077 primarily focus on firmware updates provided by NETGEAR, which address the underlying command injection flaw through proper input validation and sanitization mechanisms. Organizations and individuals should immediately upgrade affected devices to the patched firmware versions, specifically noting that RBW30 requires version 2.6.2.2 or later, while other affected models require version 3.2.17.12 or later. Network segmentation and firewall rules can provide temporary protection by limiting access to affected devices, though this approach is not a permanent solution. Additional defensive measures include disabling unnecessary services, implementing network monitoring for suspicious traffic patterns, and conducting thorough network assessments to identify potentially compromised devices. The vulnerability highlights the critical importance of maintaining up-to-date firmware and implementing robust network security practices to prevent exploitation of similar command injection vulnerabilities in other network infrastructure components.