CVE-2018-21109 in R7800
Summary
by MITRE
NETGEAR R7800 devices before 1.0.2.60 are affected by command injection by an authenticated user.
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Analysis
by VulDB Data Team • 06/02/2024
The vulnerability identified as CVE-2018-21109 affects NETGEAR R7800 wireless routers running firmware versions prior to 1.0.2.60, representing a critical command injection flaw that allows authenticated attackers to execute arbitrary commands on the affected devices. This vulnerability resides within the web-based management interface of the router, where insufficient input validation and sanitization permits malicious users with legitimate credentials to inject and execute system commands directly on the underlying operating system. The flaw specifically manifests in the handling of user-supplied input within certain administrative functions, creating a pathway for privilege escalation and system compromise that extends beyond typical administrative boundaries.
The technical implementation of this vulnerability falls under the Common Weakness Enumeration category CWE-77, which describes improper neutralization of special elements used in command execution. Attackers exploiting this vulnerability can leverage the authenticated session to submit malicious payloads through various web interface parameters, enabling them to execute arbitrary shell commands with the privileges of the web server process. The affected device architecture runs on a Linux-based embedded operating system where the command injection occurs in the context of the router's web application, allowing for complete system compromise including but not limited to network traffic interception, data exfiltration, and further lateral movement within the network. This vulnerability represents a significant risk as it requires only valid authentication credentials, which are often easily obtained through social engineering, default credential exploitation, or credential reuse attacks.
The operational impact of CVE-2018-21109 extends beyond simple privilege escalation to encompass full system compromise and potential network infiltration. Once exploited, attackers can gain persistent access to the router's command execution environment, enabling them to modify network configurations, install malicious firmware, or establish backdoors for continued access. The vulnerability creates a persistent threat vector that can be leveraged for advanced persistent threat campaigns, as the compromised router becomes a potential pivot point for attacking other networked devices. Network security monitoring systems may not immediately detect this attack vector since it operates through legitimate administrative interfaces, making detection more challenging and increasing the risk of prolonged undetected compromise. The threat landscape for this vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, specifically shell scripting, and T1021.001 for remote services, as the attack exploits legitimate remote access capabilities to achieve unauthorized system control.
Mitigation strategies for CVE-2018-21109 primarily focus on firmware updates and network segmentation. The most effective immediate solution involves upgrading the affected NETGEAR R7800 devices to firmware version 1.0.2.60 or later, which includes proper input validation and sanitization measures to prevent command injection attacks. Network administrators should also implement strict access controls and credential management policies, including mandatory password changes and multi-factor authentication where possible. Additionally, implementing network monitoring solutions that can detect unusual command execution patterns and unauthorized administrative access attempts provides valuable defense-in-depth capabilities. Security segmentation through firewall rules and access control lists can limit the potential impact of successful exploitation by restricting lateral movement within the network. Organizations should also conduct regular vulnerability assessments and penetration testing to identify similar vulnerabilities in other network infrastructure devices, as this class of vulnerability often affects multiple vendors and device types within the same product families.