ASN Threat Ranking — Most Malicious Networks Worldwide

What is an ASN?

An Autonomous System Number (ASN) is a unique identifier assigned to a network or group of networks managed by a single organization under a common routing policy. Every ISP, cloud provider, and large enterprise has one or more ASNs. For example, Amazon Web Services operates AS16509, and Cloudflare operates AS13335. When a large volume of abuse reports originate from a single ASN, it may indicate compromised infrastructure, bulletproof hosting, or inadequate abuse handling within that network.

How to Use ASN Threat Data

Network-level blocking: Instead of blocking thousands of individual IPs, firewall administrators can block or rate-limit entire ASNs known for persistent abuse. This is far more efficient and covers new IPs as they appear within that network.

Monitoring and alerting: SOC teams can set up alerts when traffic from high-risk ASNs increases, indicating potential attack campaigns. Tracking ASN-level trends over time reveals which networks are improving their abuse handling and which are deteriorating.

Threat intelligence enrichment: Integrating ASN reputation data into SIEM and SOAR platforms allows automated risk scoring. An IP from a high-risk ASN can be automatically escalated for review, while IPs from well-managed networks receive lower priority.