Free Blocklists of Suspected Malicious IPs and URLs

Several organizations maintain and publish free blocklists of IP addresses and URLs of systems and networks suspected in malicious activities on-line. Some of these lists have usage restrictions:

The lists differ in format, goals, and data collection methodology. Be sure to read about the list before making use of it. Did you notice any blocklist sources that should be on this list, but are missing? Let me know. My other lists of on-line security resources outline Automated Malware Analysis Services and On-Line Tools for Malicious Website Lookups.

Updated

About the Author

I design practical security solutions and shepherd them to a sustainable state. I used to be hands-on in many areas of cybersecurity and IT. Now I focus on strategy and leadership, treating security as an enabler that helps people and companies achieve their goals. As the CISO of Axonius, I lead the security program to earn customers' trust and fuel the company's growth. Earlier, I built security products and services. I'm also a Faculty Fellow at SANS Institute, where I help professionals develop malware analysis skills.

Learn more