Expired Domain Gave Researcher Control Over Military Base Phone Infrastructure
Original: I accidentally logged hundreds of thousands of phone calls to military bases
Why This Matters
Highlights critical gaps in legacy phone-network DNS infrastructure that remain exploitable at minimal cost.
Security researcher Lina purchased an expired domain for €5 and inadvertently gained DNS control over e164.arpa zones for three international phone codes (+290, +246, +247), logging hundreds of thousands of calls destined for military bases including Diego Garcia.
Security researcher Lina discovered that three e164.arpa zones — covering phone country codes +290 (Saint Helena), +246 (British Indian Ocean Territory/Diego Garcia), and +247 — were delegated to two nameservers, one of which (ns.enum.org.uk) had expired. By purchasing the expired domain for just €5, she gained full DNS authority over those zones.
The e164.arpa system, defined in early-2000s RFCs, translates E.164 phone numbers into DNS records so carriers can route calls over VoIP instead of traditional telephony. While the system never saw widespread adoption and is largely considered defunct, its DNS infrastructure remains live and authoritative in parts of the global phone network.
Because Lina now controlled the nameserver for those zones, DNS queries for numbers in those territories — including ENUM lookups from carriers attempting to route calls — were answered by her server. This allowed her to passively log query traffic, which she describes as amounting to hundreds of thousands of call-routing lookups, some associated with military communications infrastructure at Diego Garcia, a strategically significant U.S./UK military base.
Lina had previously reported similar DNS takeovers of .gov and .edu domains and moved on. She notes this case is more significant due to the phone-network infrastructure nature of .arpa zones. The vulnerability stems from long-neglected delegation records pointing to nameservers that were never renewed, a systemic oversight in ENUM infrastructure management.