CVE-2021-45534 in AC2100
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by command injection by an authenticated user. This affects AC2100 before 1.2.0.88, AC2400 before 1.2.0.88, AC2600 before 1.2.0.88, D7000 before 1.0.1.82, R6220 before 1.1.0.110, R6230 before 1.1.0.110, R6260 before 1.1.0.84, R6330 before 1.1.0.84, R6350 before 1.1.0.84, R6700v2 before 1.2.0.88, R6800 before 1.2.0.88, R6850 before 1.1.0.84, R6900v2 before 1.2.0.88, R7200 before 1.2.0.88, R7350 before 1.2.0.88, R7400 before 1.2.0.88, and R7450 before 1.2.0.88.
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Analysis
by VulDB Data Team • 12/28/2021
This vulnerability represents a critical command injection flaw in NETGEAR wireless routers and networking equipment that allows authenticated attackers to execute arbitrary commands on affected devices. The issue stems from insufficient input validation within the web interface of these devices, specifically in the handling of user-supplied parameters that are subsequently processed by the underlying operating system. Attackers who have gained valid credentials can exploit this weakness to bypass normal access controls and execute malicious commands with the privileges of the web server process, potentially leading to complete device compromise and unauthorized network access. The vulnerability affects a wide range of NETGEAR products including various AC and R series routers, making it particularly concerning given the widespread deployment of these devices in both residential and small business environments.
The technical implementation of this command injection vulnerability occurs through improper sanitization of input parameters within the device's web administration interface. When authenticated users submit specific parameters through web forms or API calls, the system fails to properly validate or escape these inputs before incorporating them into system commands or shell executions. This weakness aligns with CWE-77 and CWE-89, which classify command injection and SQL injection vulnerabilities respectively, though the specific implementation here involves direct operating system command execution rather than database queries. The flaw enables attackers to inject malicious shell commands that are then executed by the device's operating system, potentially allowing for remote code execution and privilege escalation. According to the ATT&CK framework, this vulnerability maps to T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, representing the attack paths an adversary would follow to leverage this weakness.
The operational impact of this vulnerability extends beyond simple device compromise to potentially enable broader network infiltration and persistent access. Once exploited, attackers can gain complete control over the affected router, allowing them to modify network configurations, redirect traffic, implement man-in-the-middle attacks, or establish persistent backdoors for future access. The vulnerability's presence in multiple device models suggests a systemic design flaw rather than isolated incidents, indicating that the underlying software architecture may not properly implement secure coding practices for input validation and command execution. Network administrators face significant challenges in identifying affected devices, as the vulnerability requires valid authentication credentials to exploit, but once compromised, the attacker can potentially maintain long-term access to the network infrastructure. The affected firmware versions span multiple generations of NETGEAR routers, suggesting that the vulnerability has existed for extended periods and could have been exploited by threat actors who obtained legitimate user credentials through various means including credential reuse attacks or social engineering.
Mitigation strategies for this vulnerability require immediate firmware updates from NETGEAR, as the company has released patches addressing the command injection flaw in versions 1.2.0.88 and later. Organizations should implement comprehensive inventory management to identify all affected devices within their network infrastructure, particularly focusing on legacy router models that may not receive regular updates. Network segmentation and access control measures should be strengthened to limit the potential impact of compromised devices, while monitoring systems should be deployed to detect unusual network traffic patterns that might indicate exploitation attempts. Additionally, implementing strong authentication controls including multi-factor authentication and regular credential rotation can reduce the likelihood of unauthorized access, though this does not prevent exploitation once credentials have been compromised. Security teams should also consider network-wide scanning for vulnerable devices and establish incident response procedures for rapid remediation of compromised systems. The vulnerability highlights the importance of secure coding practices and regular security assessments, particularly for network infrastructure devices that are often overlooked in traditional security monitoring and penetration testing activities.