CVE-2021-38529 in D7800
Summary
by MITRE • 08/11/2021
Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects D7800 before 1.0.1.56, R7800 before 1.0.2.68, R8900 before 1.0.4.26, and R9000 before 1.0.4.26.
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Analysis
by VulDB Data Team • 08/16/2021
This vulnerability represents a critical command injection flaw in NETGEAR networking equipment that allows unauthenticated attackers to execute arbitrary commands on affected devices. The vulnerability affects multiple models including the D7800, R7800, R8900, and R9000 routers, with specific version ranges indicating the scope of impacted firmware releases. The flaw stems from insufficient input validation and sanitization within the device's web interface or management protocols, creating an avenue for remote code execution without requiring authentication credentials.
The technical implementation of this vulnerability involves the improper handling of user-supplied input that flows directly into system commands without adequate filtering or escaping mechanisms. Attackers can craft malicious payloads that, when submitted through web forms or API endpoints, get interpreted and executed by the underlying operating system. This type of vulnerability falls under CWE-77 which specifically addresses command injection flaws in software systems. The impact is particularly severe because it affects the core network infrastructure devices that are typically deployed in home and small office environments where security monitoring may be limited.
From an operational perspective, this vulnerability creates significant risk for affected networks as attackers can gain full administrative control over the impacted routers. The unauthenticated nature means that no prior access or credentials are required to exploit the flaw, making it particularly dangerous for widespread deployment. Once exploited, attackers can modify router configurations, redirect traffic, install malware, or use the compromised device as a pivot point for attacking other systems within the network. This aligns with ATT&CK technique T1059 which covers command and scripting interpreter, and T1021 which addresses remote services.
The affected device models represent a substantial portion of NETGEAR's consumer and small business product line, indicating that the vulnerability could potentially impact thousands of devices globally. The firmware version ranges suggest that this was likely a known issue that was addressed in subsequent patches, but many users may not have updated their devices. Organizations and individuals should immediately implement network segmentation to limit the potential impact, disable unnecessary services, and ensure firmware updates are applied to all affected devices. Network monitoring should be enhanced to detect unusual traffic patterns that might indicate exploitation attempts, and security teams should consider conducting vulnerability assessments to identify any devices that may still be running vulnerable firmware versions.