TCPTraceroute to Bypass the Firewall filters

Introduction

The first step for penetration testers is getting information about the system. Traceroute is a great tool for this purpose.

Traceroute shows the route between you and the target machine.  Linux has a command line utility called traceroute.

traceroute uses UDP.

Windows has a tool called tracert.

tracert uses ICMP.

It is quite common for firewalls to be configured to block ICMP or UDP and thereby prevent Traceroute from returning useable information.

One program designed to get around this issue is Michael Toren’s TCPTraceroute.

TCPTraceroute uses TCP SYNpackets insted of ICMP or UDP and is able to bypass common firewall filters.

Installation

TCPTraceroute is currently available for only Linux. You can install on your debian based machine by using apt-get:

sudo apt-get install tcptraceroute

Example

Summary

As a penetration tester to gain information about the target system, you need to be familiar with several tools. One of these tools is tcptraceroute. It can bypass most of the firewalls since it uses TCP unlike tracert and traceroute.