Nessus is highly regarded for its massive, frequently updated database of vulnerability signatures (plugins) and its low false-positive rate. Tenable offers a limited free tier called , but it comes with restrictions that push users to look for cracks:
Instead, consider using the free trial or Nessus Essentials to get started with the scanner. If you're interested in using Nessus for commercial purposes, I recommend purchasing a license from Tenable or an authorized reseller.
The interface and setup can have a steeper learning curve than Nessus. 3. Nuclei or Nmap (Lightweight Scanning)