A particular malware contacted its command and control servers via procedurally generated domain names (to make it difficult to shut down just a single domain t

A particular malware contacted its command and control servers via procedurally generated domain names (to make it difficult to shut down just a single domain that controlled it). Malware researchers reversed a sample of the malware and started blackholing domains that matched the pattern to get ahead of the malware by preventing it from communicating with the domain du jour. It just so happens that the authors domain pattern-matched domains that would be contacted by the malware.