What Is ASN Abuse?

An ASN (Autonomous System Number) identifies the networks that route traffic across the internet. When attackers repeatedly operate from the same networks, abuse can cluster at the ASN level. That pattern is called ASN abuse, and it is one of the clearest signals for large-scale malicious activity.

FraudGuard surfaces ASN and network attribution in every lookup so security teams can identify abuse patterns beyond a single IP.

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Why ASN Abuse Matters

• Scale: Malicious activity often appears across whole ranges, not just one IP.
• Attribution: ASN data shows which networks are repeatedly associated with abuse.
• Policy enforcement: ASN patterns inform blocking, rate limiting, or monitoring decisions.

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Common Signs of ASN Abuse

• Repeated threats from the same ASN across multiple IPs
• Concentrated abuse from hosting or VPS providers
• Recurring bot activity tied to specific network ranges

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How to Investigate ASN Abuse

• Start with IP reputation to confirm risk and threat type.
• Check network attribution to see the ASN and provider.
• Expand the search across the ASN or range to verify patterns.
• Apply consistent controls across the offending network.

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How FraudGuard Helps

FraudGuard provides attribution and threat intelligence that make ASN-based investigations fast and reliable:

• IP Lookup for immediate ASN and provider context
• Advanced Threat Lookup to research abuse by ASN, ISP, or organization
• Expand to bulk lookup v3 if you need to evaluate ranges or many IPs at once.
• For large-scale enforcement, the Offline Threat Database provides a near real-time copy of ACE.

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Summary

ASN abuse is a network-level signal that helps you move beyond one-off IP blocks to systematic enforcement. FraudGuard makes it easy to identify abusive networks and respond consistently across entire ranges.

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Explore the full IP Reputation & Abuse Guide for related topics.

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