DDoS Knowledge · Business Guide

RST Flood Attack: Forged Resets That Drop Real Sessions

An RST flood sends forged TCP reset packets aimed at forcing established, legitimate connections to close early — a targeted disruption of active sessions rather than pure resource exhaustion.

Written for business and infrastructure decision-makers, not protocol engineers.

What It Is

What is a RST Flood?

A TCP RST packet normally signals an abrupt, abnormal connection close. During an RST flood, attackers send forged resets that attempt to match an active connection's source, sequence number, and state closely enough to be accepted, terminating a session the two real endpoints never intended to close.

Think of someone impersonating a customer to cancel their own live order

If the cancellation isn't checked against the actual order details, it goes through and the real customer's transaction is interrupted. An RST flood works the same way against active network sessions — forged resets that aren't checked against real connection state can end them prematurely.

Business Impact

The attack happens in the network.
The consequences happen to the business.

Customers may see slow or unavailable services

Availability risk that belongs in business-continuity planning.

Transactions, sessions or gameplay can be interrupted

Availability risk that belongs in business-continuity planning.

Firewalls and shared network infrastructure can come under pressure

Availability risk that belongs in business-continuity planning.

Support and operations teams get pulled into incident response

Availability risk that belongs in business-continuity planning.

Context

Why this attack matters.

RST-based attacks matter because they can disrupt specific active sessions — video calls, trading connections, gameplay — rather than only degrading capacity broadly. That makes them relevant even to services with otherwise ample bandwidth and connection headroom.

Leadership does not need to understand every packet field. It needs to know whether legitimate customers can keep using the service during an attack.
Who Should Care

Most relevant where internet availability is part of the product.

ISPs & Datacenters

Attacks against one customer can become an infrastructure and service-quality issue.

Hosting & Gaming

Availability, latency and shared network resources are immediately visible to end users.

SaaS & Online Business

If users cannot connect, they cannot transact, work or consume the service they pay for.

Executive Checklist

Questions to ask your technology team.

NeuroWall

NeuroWall helps protect against rst flood attacks.

NeuroWall validates RST source, sequence, and state before honoring it, off by default alongside FIN validation for the same false-positive-avoidance rationale — protecting active sessions from forged resets once enabled.

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FAQ

Frequently asked questions about RST Flood attacks

What is an RST flood attack?

An RST flood sends forged TCP reset packets attempting to match an active connection closely enough to force it closed prematurely.

How is an RST flood different from a FIN flood?

A FIN flood mainly targets processing capacity with bogus teardown packets for connections that don't exist. An RST flood targets specific real, active connections to disrupt them.

What kinds of services are most exposed to RST floods?

Long-lived connections — video calls, trading platforms, gaming sessions — where prematurely closing one active session has an immediate, visible impact on a real user.

Is an RST flood a DDoS attack?

It can be. When distributed sources generate the traffic simultaneously, it is a distributed denial-of-service attack.

Does NeuroWall help with RST floods?

Yes. NeuroWall validates RST source, sequence, and state before honoring resets, as part of its DDoS protection capabilities.

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