IPv4 addresses are valuable, so criminals are figuring out how to buy or steal them.

Hence criminals’ interest in ways to land themselves IP addresses, some of which were detailed this week by ARIN’s senior director of global registry knowledge, Leslie Nobile, at the North American Network Operators Group’s NANOG 67 conference.

Nobile explained that criminals look for dormant ARIN records and try to establish themselves as the rightful administrator. ARIN has 30,556 legacy network records, she said, but a validated point of contact for only 54 per cent of those networks. The remaining ~14,000 networks are ripe for targeting by hijackers who Nobile said are only interested in establishing legitimacy with ARIN so they can find a buyer for unused IPv4 addresses possessed by dormant legacy networks.

Criminals do so by finding dormant ARIN records and Whois data to see if there is a valid contact, then ascertaining if IPv4 allocations are currently routed. If the assigned addresses are dark and no active administrator exists, hijackers can revive dormant domain names or even re-register the names of defunct companies in order to establish a position as legitimate administrators of an address space. If all goes well, the hijackers end up with addresses to sell.