Understanding IPv4 Abuse

IPv4 “abuse” is a catch-all for people or organizations who use IPv4 addresses for inappropriate purposes: spam and phishing, malware control servers, botnets on compromised devices, DDoS attacks, and routing shenanigans like BGP hijacks. Because IPv4 is a scarce, tradable resource, abuse also includes fraud in the transfer/lease market — sold or leased blocks being used for malicious campaigns after the deal closes. That mix makes the problem technical, legal, and economic all at once.^[1]

How Abuse is Handled

There isn’t a single sheriff. Handling IPv4 abuse is a collaborative ecosystem:

• Network operators and hosting providers detect and mitigate attack traffic on their infrastructure.
• Blocklists and threat-intel providers (such as Spamhaus) publish IPs tied to abuse so mail servers and firewalls can block them.^[2]
• Regional Internet Registries (RIRs) like ARIN, RIPE, and APNIC keep records of who “holds” which IPs and offer reporting guidance — but they don’t operate like police; they primarily manage registry data and policy and pass evidence along where appropriate.^[3]
• Newer technical controls — RPKI and route origin validation — aim to reduce BGP hijacks by cryptographically proving who is allowed to announce which prefix, though deployment remains incomplete.^[4]

Practical defenses are a mix of automation and human work: automated abuse detection, sinkholing malicious command-and-control servers, working with hosting providers to take down offending servers, and using blocklists to stop spam and phishing. Contracts and due diligence in the IP transfer and lease market — including blacklist checks, reputation monitoring, and abuse clauses — are increasingly common to reduce post-transfer risk.^[5]

Is Abuse Getting Better or Worse?

Short answer: complicated. Some abuse categories are improving thanks to automation, better threat intelligence, and improved market hygiene. Email spam operators have fewer cheap or disposable vectors than a decade ago because blocklists and reputation systems are effective when broadly adopted. But other problems have persisted or worsened: IoT compromise and botnets remain a major source of ongoing abuse, and BGP incidents — including mis-announcements and hijacks — continue due to incomplete RPKI and ROV adoption.^[1][4]

What Actually Helps – If you run networks or own IP space, practical steps include publishing and monitoring an abuse contact, implementing sensible rate limits and outbound filtering, using threat feeds and blocklists, requiring abuse clauses and reputation checks in transfer or lease contracts, and deploying RPKI and ROV where possible. Industry coordination — fast reporting, clear ownership data, and automation — consistently reduces exposure.

Final Thoughts
IPv4 abuse has not disappeared. Defenders have become more automated and effective at detecting and mitigating many attacks, but adversaries adapt, and structural factors — scarcity, legacy address space, partial RPKI deployment, and insecure IoT ecosystems — continue to create opportunities for abuse. The result is incremental progress alongside ongoing challenges, reinforcing the need to pair technical controls with stronger market and contractual hygiene.

References

1. RIPE Labs
2. The Spamhaus Project
3. ARIN (American Registry for Internet Numbers)
4. Cloudflare Blog
5. CAIDA (Center for Applied Internet Data Analysis)