A command injection vulnerability has been found on D-Link DIR-823G devices with firmware version 1.02B03 that allows an attacker to execute arbitrary operating system commands through well-designed /HNAP1 requests. Before the HNAP API function can process the request, the system function executes an untrusted command that triggers the vulnerability.
https://www.dlink.com/en/security-bulletin/
https://github.com/RobinWang825/IoT_vuln/tree/main/D-Link/DIR-823G/2
https://github.com/726232111/VulIoT/tree/main/D-Link/DIR823G%20V1.0.2B05/HNAP1