MalwareDomains.com provides a DNS blocklist of known malware domains. This list is natively used as a part of DNS configuration, however, the below tool will allow you to import the domains.txt definitions file into ISA Server as a URL Set or DNS Set. You can then create a deny access rule based on the imported list.
Note that I have not tested this application yet, so use at your own risk 🙂
Check it out at:
Thomas W Shinder, M.D.
GET THE NEW BOOK! Go to http://tinyurl.com/2gpoo8
MVP — Microsoft Firewalls (ISA)