Cracking the Wall of Confinement - Understanding and Analyzing Malicious Domain Take-downs.

Take-down operations aim to disrupt cybercrime involving malicious domains. In the past decade, many successful take-down operations have been reported, including those against the Conficker worm, and most recently, against VPNFilter. Although it plays an important role in fighting cybercrime, the domain take-down procedure is still surprisingly opaque. There seems to be no in-depth understanding about how the take-down operation works and whether there is due diligence to ensure its security and reliability. In this paper, we report the first systematic study on domain takedown. Our study was made possible via a large collection of data, including various sinkhole feeds and blacklists, passive DNS data spanning six years, and historical WHOIS information. Over these datasets, we built a unique methodology that extensively used various reverse lookups and other data analysis techniques to address the challenges in identifying taken-down domains, sinkhole operators, and take-down durations. Applying the methodology on the data, we discovered over 620K taken-down domains and conducted a longitudinal analysis on the take-down process, thus facilitating a better understanding of the operation and its weaknesses. We found that more than 14% of domains taken-down over the past ten months have been released back to the domain market and that some of the released domains have been repurchased by the malicious actor again before being captured and seized, either by the same or different sinkholes. In addition, we showed that the misconfiguration of DNS records corresponding to the sinkholed domains allowed us to hijack a domain that was seized by the FBI. Further, we found that expired sinkholes have caused the transfer of around 30K taken-down domains whose traffic is now under the control of new owners.