CVE-2021-45659 in RBK40
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by server-side injection. This affects RBK40 before 2.5.1.16, RBR40 before 2.5.1.16, RBS40 before 2.5.1.16, RBK20 before 2.5.1.16, RBR20 before 2.5.1.16, RBS20 before 2.5.1.16, RBK50 before 2.5.1.16, RBR50 before 2.5.1.16, RBS50 before 2.5.1.16, and RBS50Y before 2.6.1.40.
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Analysis
by VulDB Data Team • 12/28/2021
This vulnerability represents a critical server-side injection flaw affecting multiple NETGEAR router models including RBK40, RBR40, RBS40, RBK20, RBR20, RBS20, RBK50, RBR50, RBS50, and RBS50Y. The issue stems from inadequate input validation and sanitization within the web interface of these devices, creating an avenue for malicious actors to inject arbitrary commands or code into the server-side processing layer. The vulnerability impacts firmware versions prior to 2.5.1.16 for most models and 2.6.1.40 for RBS50Y, indicating a widespread issue across NETGEAR's consumer and small office networking equipment portfolio. From a cybersecurity perspective, this vulnerability aligns with CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and represents a significant risk to network infrastructure security.
The technical exploitation of this server-side injection vulnerability allows attackers to execute arbitrary commands on the affected devices with the privileges of the web server process. This typically occurs when user-supplied input is directly processed by the server without proper sanitization or validation, enabling attackers to manipulate the application's behavior through crafted inputs. The affected NETGEAR devices are particularly vulnerable because they process web interface requests without sufficient security controls to prevent malicious input from being interpreted as executable code. This type of vulnerability creates a persistent threat vector that can be exploited by remote attackers without requiring physical access to the devices, making it particularly dangerous in enterprise and home networking environments where these routers serve as primary network gateways.
The operational impact of this vulnerability extends beyond simple command execution, potentially enabling complete compromise of the affected networking equipment. Attackers could leverage this vulnerability to gain unauthorized access to the device's administrative interface, modify network configurations, redirect traffic, or establish persistent backdoors within the network infrastructure. The implications are severe given that these devices often serve as the first line of defense in network security, providing routing, firewall, and NAT services. From an ATT&CK framework perspective, this vulnerability maps to techniques such as T1059.001 (Command and Scripting Interpreter: PowerShell) and T1071.004 (Application Layer Protocol: DNS) where attackers could potentially use the compromised devices as command and control infrastructure or to conduct DNS tunneling attacks. The vulnerability also enables lateral movement within networks as compromised routers can be used to pivot to other network segments.
Mitigation strategies for this vulnerability should include immediate firmware updates to the latest versions that address the injection flaw, as provided by NETGEAR in their security advisories. Network administrators should also implement network segmentation to limit the potential impact of a compromised device and deploy intrusion detection systems to monitor for suspicious traffic patterns that might indicate exploitation attempts. Additional protective measures include disabling unnecessary web interfaces, implementing strong authentication mechanisms, and regularly auditing network configurations to identify any unauthorized changes that might result from exploitation. Organizations should also consider conducting vulnerability assessments specifically targeting network infrastructure devices to identify similar vulnerabilities across their entire network ecosystem. The remediation process must be prioritized at the highest security level due to the potential for complete network compromise and the critical role these devices play in maintaining network security boundaries.