Blocklists of Suspected Malicious IPs and URLs

Several organizations maintain and publish blocklists (a.k.a blacklists) of IP addresses and URLs of systems and networks suspected in malicious activities on-line. Many of these lists are available for free; some 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.

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About the Author

Lenny Zeltser develops teams, solutions, and programs that use information security to achieve business results. Over the past two decades, Lenny has been leading efforts to establish resilient security practices and solve hard security problems. As a respected author and speaker, he has been advancing cybersecurity tradecraft and contributing to the community. His insights build upon 20 years of real-world experiences, a Computer Science degree from the University of Pennsylvania, and an MBA degree from MIT Sloan.

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