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 is a business and tech leader with extensive experience in information technology and security. His areas of expertise include incident response, cloud services and product management. Lenny focuses on safeguarding customers' IT operations at NCR Corporation. He also teaches digital forensics and anti-malware courses at SANS Institute. Lenny frequently speaks at conferences, writes articles and has co-authored books. He has earned the prestigious GIAC Security Expert designation, has an MBA from MIT Sloan and a Computer Science degree from the University of Pennsylvania.

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