CVE-2019-7297 in DIR-823G
Summary
by MITRE
An issue was discovered on D-Link DIR-823G devices with firmware through 1.02B03. A command Injection vulnerability allows attackers to execute arbitrary OS commands via shell metacharacters in a crafted /HNAP1 request. This occurs when the GetNetworkTomographyResult function calls the system function with an untrusted input parameter named Address. Consequently, an attacker can execute any command remotely when they control this input.
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Analysis
by VulDB Data Team • 07/04/2023
The CVE-2019-7297 vulnerability represents a critical command injection flaw in D-Link DIR-823G wireless routers running firmware versions up to 1.02B03. This vulnerability resides within the device's web management interface and specifically targets the HNAP1 protocol implementation. The flaw manifests when the GetNetworkTomographyResult function processes incoming requests without adequate input validation, creating a pathway for remote code execution through carefully crafted shell metacharacters. The vulnerability is particularly concerning as it operates at the system level, allowing attackers to execute arbitrary operating system commands directly on the affected device. The attack vector involves sending a malicious HNAP1 request containing shell metacharacters that get processed by the system function, thereby bypassing normal security controls. This type of vulnerability falls under CWE-77 which categorizes command injection flaws, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter. The severity of this vulnerability is amplified by the fact that it requires no authentication, making it accessible to any remote attacker who can reach the device's management interface.
The technical exploitation of this vulnerability occurs through the improper handling of user-supplied input within the Address parameter of the GetNetworkTomographyResult function. When an attacker crafts a malicious HNAP1 request with shell metacharacters embedded in the Address field, the system function system() processes this unvalidated input directly without proper sanitization or escaping. This creates a classic command injection scenario where attacker-controlled commands are executed with the privileges of the web server process, typically running with elevated system privileges. The vulnerability demonstrates poor input validation practices and highlights the critical importance of sanitizing all user inputs before processing them in system calls. The device's firmware fails to implement proper parameter validation or escaping mechanisms, allowing metacharacters such as semicolons, pipes, and ampersands to be interpreted by the underlying shell. This flaw represents a fundamental security weakness in the device's input handling architecture and exposes the entire network to potential compromise.
The operational impact of CVE-2019-7297 extends beyond simple remote code execution to encompass complete network compromise and persistent backdoor access. Once exploited, attackers can gain full control over the router's operating system, potentially installing malware, modifying network configurations, redirecting traffic, or establishing persistent access points. The vulnerability enables attackers to perform reconnaissance activities such as port scanning, network mapping, and information gathering from within the local network. Furthermore, the compromised router can serve as a launching point for attacks against other devices on the network, creating a potential pivot point for lateral movement. The persistent nature of this vulnerability means that even if the initial attack is detected and mitigated, the device remains vulnerable until firmware is updated. This poses significant risks for enterprise environments where multiple devices may be affected, potentially creating widespread network compromise. Organizations using these devices face potential data exfiltration, network disruption, and service availability issues that could impact business operations.
Mitigation strategies for CVE-2019-7297 must address both immediate remediation and long-term security improvements. The primary recommendation involves updating the device firmware to the latest version provided by D-Link, which contains patches for this specific vulnerability. Network administrators should also implement network segmentation and access controls to limit exposure of these devices to untrusted networks. The vulnerability highlights the importance of proper input validation and output encoding practices in web applications, particularly those interfacing with system-level functions. Organizations should deploy network monitoring solutions to detect suspicious HNAP1 traffic patterns and command injection attempts. Additionally, implementing web application firewalls can help detect and block malicious requests before they reach the vulnerable functions. The security community should emphasize the critical need for regular firmware updates and security assessments of network infrastructure devices. This vulnerability serves as a reminder of the importance of secure coding practices and proper input validation, particularly when dealing with system-level calls that can execute arbitrary commands. Organizations should also consider implementing intrusion detection systems specifically configured to identify command injection attempts and other exploitation patterns targeting network infrastructure devices.