Verizon Accused of Routing Millions of IP Addresses for Cybercriminals
US network operator Verizon Communications is routing over 4 million IP addresses that are currently in the hands of cybercriminals, researchers at The Spamhaus Project reveal. — Spammers have been acquiring large ranges …
Context & Ripple Effects
Spamhaus's finding lands a year after Verizon patched a flaw that let attackers forge customer IP addresses to hijack accounts — the second time in twelve months the carrier's handling of address space has surfaced as an attack surface rather than just plumbing.
It also foreshadows a pattern the corpus keeps returning to: three years later Verizon would accept a rogue route and knock Cloudflare, Facebook, and Amazon offline regionally (the 2019 BGP misconfiguration outage), and in 2022 it was again chasing abuse on its own network after customers got spam texts from their own numbers.
First-order effects
- Over 4 million IP addresses under Verizon's routing umbrella now serve cybercriminal traffic, so spammers inherit the deliverability of a tier-one carrier's address space while blocklists hesitate to touch it.
- Verizon faces direct pressure from Spamhaus and its feed subscribers to reclaim or de-peer the hijacked ranges, an abuse-desk and engineering burden it did not plan for.
Second-order effects
- Downstream networks and email operators must build prefix-level filters against specific Verizon announcements instead of trusting the carrier wholesale, eroding the default trust that makes transit from a major operator valuable.
- Rival carriers face the same audit: if criminals can quietly acquire large legacy ranges inside a reputable network, every operator's unused address inventory becomes a liability competitors and customers will ask about.
Third-order effects
- As IPv4 exhaustion makes clean address space scarce, criminal acquisition of dormant ranges pushes the industry toward verifiable routing provenance — prefix filtering and registry hygiene shift from best practice to a condition of peering and transit.
- If large carriers keep absorbing abuse they did not originate, reputation systems for IP space consolidate around third-party monitors like Spamhaus, giving blocklist operators structural leverage over tier-one routing decisions.
The trend: IP address space is becoming a contested asset: as clean IPv4 grows scarce, who routes a range matters more than who owns it, pulling carriers into an enforcement role they historically avoided.