fragrouter Package Description

Fragrouter is a network intrusion detection evasion toolkit. It implements most of the attacks described in the Secure Networks “Insertion, Evasion, and Denial of Service: Eluding Network Intrusion Detection” paper of January 1998.

This program was written in the hopes that a more precise testing methodology might be applied to the area of network intrusion detection, which is still a black art at best.

Conceptually, fragrouter is just a one-way fragmenting router – IP packets get sent from the attacker to the fragrouter, which transforms them into a fragmented data stream to forward to the victim.

Source: fragrouter README

fragrouter Homepage | Kali fragrouter Repo

  • Author: Dug Song, Anzen Computing
  • License: GPLv2

Tools included in the fragrouter package

fragrouter – IDS evasion toolkit
root@kali:~# fragrouter
Version 1.6
Usage: fragrouter [-i interface] [-p] [-g hop] [-G hopcount] ATTACK

where ATTACK is one of the following:

-B1: base-1: normal IP forwarding
-F1: frag-1: ordered 8-byte IP fragments
-F2: frag-2: ordered 24-byte IP fragments
-F3: frag-3: ordered 8-byte IP fragments, one out of order
-F4: frag-4: ordered 8-byte IP fragments, one duplicate
-F5: frag-5: out of order 8-byte fragments, one duplicate
-F6: frag-6: ordered 8-byte fragments, marked last frag first
-F7: frag-7: ordered 16-byte fragments, fwd-overwriting
-T1: tcp-1: 3-whs, bad TCP checksum FIN/RST, ordered 1-byte segments
-T3: tcp-3: 3-whs, ordered 1-byte segments, one duplicate
-T4: tcp-4: 3-whs, ordered 1-byte segments, one overwriting
-T5: tcp-5: 3-whs, ordered 2-byte segments, fwd-overwriting
-T7: tcp-7: 3-whs, ordered 1-byte segments, interleaved null segments
-T8: tcp-8: 3-whs, ordered 1-byte segments, one out of order
-T9: tcp-9: 3-whs, out of order 1-byte segments
-C2: tcbc-2: 3-whs, ordered 1-byte segments, interleaved SYNs
-C3: tcbc-3: ordered 1-byte null segments, 3-whs, ordered 1-byte segments
-R1: tcbt-1: 3-whs, RST, 3-whs, ordered 1-byte segments
-I2: ins-2: 3-whs, ordered 1-byte segments, bad TCP checksums
-I3: ins-3: 3-whs, ordered 1-byte segments, no ACK set
-M1: misc-1: Windows NT 4 SP2 - http://www.dataprotect.com/ntfrag/
-M2: misc-2: Linux IP chains - http://www.dataprotect.com/ipchains/

fragrouter Usage Example

Using interface eth0 (-i eth0), send ordered 8-byte IP fragments (-F1):

root@kali:~# fragrouter -i eth0 -F1
fragrouter: frag-1: ordered 8-byte IP fragments
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