pdlist. A passive subdomain finder

Author: gnc

Copyright: © 2019, gnc.

Date: 2019-07-25

Version: 0.1.0

PURPOSE

pdlist is a passive subdomain finder written in python3. This tool can be used effectively to collect information about a domain without ever sending a single packet to any of its hosts. Given a domain like "example.com" it will find all the hosts which have a hostname <something>.example.com or URLs strictly related to example.com.

In order to collect informations about subdomains the software queries different publicly available websites, which at the moment are:

• threatcrowd
• urlscan
• hackertarget
• dnsdumpster
• crt.sh
• certspotter

pdlist is very user-friendly and lightweight since the only dependencies are the following python modules:

• requests
• dnsdumpster

INSTALLATION

We can install pdlist simply by doing:

git clone https://github.com/gnebbia/pdlist
cd pdlist
pip install -r requirements.txt
python setup.py install

Notice that both pip and python should refer to version 3, so if you are not using pyenv as I am doing you should probably substitute pip with pip3 and python with python3.

USAGE

To have a list of subdomains passively of for example example.com we can do:

pdlist example.com

we can also specify multiple domains, e.g.,;

pdlist example1.com example2.com

We can save the output in a text file by doing:

pdlist example.com -o example-list.txt

Notice that by default pdlist will also output hostnames which may not really be proper subdomains of the specified domains, and this happens because those subdomains are still related to the specified domains.

If we want to only output proper subdomains we can enable the strict mode by doing:

pdlist example.com --strict

A usage example in the gif below:

NOTES

This is a minimalist passive domain finder, the aim of this project is to have few dependencies, small code footprint and easily extensible.

If you want to extend the code it is enough to add a module in the source package with a def parse(domains) method.

TODO

• Add more passive recon sources
• Modify the code to work in asynchrounous mode
• Generate fancy html reports

COPYRIGHT

Copyright © 2019, gnc. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions, and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions, and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. Neither the name of the author of this software nor the names of contributors to this software may be used to endorse or promote products derived from this software without specific prior written consent.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.