A Very Strange Thing Happened On The Internet

kentik  |  Last month, astute contributors to the NANOG listserv highlighted the oddity of massive amounts of DoD address space being announced by what appeared to be a shell company. While a BGP hijack was ruled out, the exact purpose was still unclear. Until yesterday when the Department of Defense provided an explanation to reporters from the Washington Post about this unusual internet development. Their statement said:

Defense Digital Service (DDS) authorized a pilot effort advertising DoD Internet Protocol (IP) space using Border Gateway Protocol (BGP). This pilot will assess, evaluate and prevent unauthorized use of DoD IP address space. Additionally, this pilot may identify potential vulnerabilities. This is one of DoD’s many efforts focused on continually improving our cyber posture and defense in response to advanced persistent threats. We are partnering throughout DoD to ensure potential vulnerabilities are mitigated.

I interpret this to mean that the objectives of this effort are twofold. First, to announce this address space to scare off any would-be squatters, and secondly, to collect a massive amount of background internet traffic for threat intelligence.

On the first point, there is a vast world of fraudulent BGP routing out there. As I’ve documented over the years, various types of bad actors use unrouted address space to bypass blocklists in order to send spam and other types of malicious traffic.

On the second, there is a lot of background noise that can be scooped up when announcing large ranges of IPv4 address space. A recent example is Cloudflare’s announcement of 1.1.1.0/24 and 1.0.0.0/24 in 2018.

For decades, internet routing operated with a widespread assumption that ASes didn’t route these prefixes on the internet (perhaps because they were canonical examples from networking textbooks). According to their blog post soon after the launch, Cloudflare received “~10Gbps of unsolicited background traffic” on their interfaces.

And that was just for 512 IPv4 addresses! Of course, those addresses were very special, but it stands to reason that 175 million IPv4 addresses will attract orders of magnitude more traffic. More misconfigured devices and networks that mistakenly assumed that all of this DoD address space would never see the light of day.

Conclusion

While today’s statement from the DoD answers some questions, much remains a mystery. Why did the DoD not just announce this address space themselves instead of directing an outside entity to use the AS of a long dormant email marketing firm? Why did it come to life in the final moments of the previous administration?

We likely won’t get all of the answers anytime soon, but we can certainly hope that the DoD uses the threat intel gleaned from the large amounts of background traffic for the benefit of everyone. Maybe they could come to a NANOG conference and present about the troves of erroneous traffic being sent their way.