CVE-2019-20757 in R7800
Summary
by MITRE
NETGEAR R7800 devices before 1.0.2.62 are affected by command injection by an authenticated user.
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Analysis
by VulDB Data Team • 05/31/2024
The CVE-2019-20757 vulnerability represents a critical command injection flaw affecting NETGEAR R7800 wireless routers running firmware versions prior to 1.0.2.62. This vulnerability resides within the web interface authentication subsystem, where an authenticated attacker can exploit improper input validation mechanisms to inject malicious commands that execute with administrative privileges. The flaw stems from inadequate sanitization of user-supplied parameters passed to system commands, creating a pathway for arbitrary code execution within the router's operating environment. The vulnerability is particularly concerning as it requires only valid authentication credentials, which are commonly obtained through default credentials or credential reuse attacks, making it accessible to a broad range of threat actors.
The technical implementation of this command injection vulnerability occurs in the router's web management interface where user inputs are directly incorporated into system calls without proper validation or escaping mechanisms. Attackers can leverage this weakness by crafting malicious payloads in specific input fields that correspond to parameters handling network configuration or system commands. When the router processes these inputs, the unsanitized data gets executed as shell commands, allowing attackers to gain full administrative control over the device. This vulnerability maps directly to CWE-77 and CWE-89, representing command injection and SQL injection categories respectively, with the execution occurring at the operating system level rather than database level. The ATT&CK framework categorizes this as a privilege escalation technique, specifically targeting the execution of malicious commands with elevated privileges.
The operational impact of CVE-2019-20757 extends far beyond simple unauthorized access, as compromised routers can serve as persistent footholds within corporate or home networks. Once an attacker gains administrative control, they can modify network configurations, redirect traffic through malicious servers, install backdoors, or use the device as a launching point for lateral movement attacks against other networked systems. The router's position as a network gateway makes it an attractive target for attackers seeking to maintain persistent access while evading detection, as the compromised device can act as a stealthy pivot point for reconnaissance and data exfiltration activities. Additionally, the vulnerability can be exploited to create persistent command execution mechanisms that survive router reboots, enabling long-term network infiltration.
Mitigation strategies for CVE-2019-20757 center on immediate firmware updates to version 1.0.2.62 or later, which contain proper input validation and sanitization mechanisms. Network administrators should also implement strict access controls including disabling unnecessary services, enforcing strong authentication practices, and regularly auditing network device configurations. The vulnerability highlights the importance of secure coding practices, particularly in web interfaces handling user inputs, and emphasizes the need for comprehensive input validation at multiple layers of application architecture. Organizations should conduct regular vulnerability assessments of network infrastructure to identify similar authentication-based command injection vulnerabilities in other devices. Security monitoring should include detection of anomalous command execution patterns and unusual network behavior originating from router addresses, as these may indicate exploitation of this and similar vulnerabilities.