Fragrouter – IP Fragmentation Attack Tool

Fragrouter is a tool used for routing network packets in a way that allows testing Intrusion Detection Systems (IDS) and firewalls. It helps in evaluating how well these security systems can handle fragmented IP traffic. Attackers may use fragmentation techniques to evade detection, making fragrouter a valuable tool for security testing.

• Performs IP fragmentation-based evasion techniques.
• Useful for testing IDS/IPS detection capabilities.
• Allows forwarding of packets while modifying fragmentation behavior.
• Simulates different types of attacks.

Install Fragrouter

Fragrouter comes pre-installed in Kali Linux. If it is not available, you can install it using the following command:

$ sudo apt-get install fragrouter

Usage of Fragrouter

To start fragrouter with a specific attack mode, use the following command:

$ sudo fragrouter -B1

In this example, -B1 specifies the fragmentation technique to be used. There are different modes available, each representing a different attack method.

 

Fragrouter Modes

Fragrouter supports multiple modes that simulate various fragmentation attacks.

Some common ones include:

• -B1 – IP fragmentation of outbound packets.
• -B2 – IP fragmentation with tiny fragments.
• -B3 – IP fragmentation with overlapping fragments.
• -B4 – IP fragmentation with fragments out of order.

Examples

To use fragrouter to fragment packets and evade detection:

$ sudo fragrouter -B1

This will intercept and modify packets before forwarding them.

Stopping Fragrouter

To stop fragrouter, use:

$ sudo killall fragrouter

Fragrouter is a powerful tool for security researchers to test IDS and firewall resilience against fragmentation attacks. Understanding its usage helps in strengthening network defenses.