⚽ Live Match: linux unix/altdns subdomain discovery through alterations and permutations

AltDNS is an open-source reconnaissance tool designed to expand the attack surface by generating potential subdomains from an existing list of known subdomains. It helps penetration testers and security researchers uncover hidden assets that may not be found through traditional subdomain enumeration techniques.

Generates permutations and alterations of existing subdomains.
Validates generated subdomains using DNS resolution.
Identifies hidden and misconfigured subdomains.
Creates customizable wordlists for enumeration.
Lightweight and Python-based for easy deployment.
Supports large-scale reconnaissance engagements.
Produces separate outputs for generated candidates and resolved subdomains.

Note: Make Sure You have Python Installed on your System, as this is python-based tool. For more information, refer to the article Python Installation Steps on Linux

Installation of AltDNS on Kali Linux

Step 1: Open the terminal and navigate to the Desktop.

cd Desktop

Step 2: Create a directory for AltDNS.

mkdir Altdns

Step 3: Move into the newly created directory.

cd Altdns

Step 4: Clone the AltDNS repository from GitHub.

git clone https://github.com/infosec-au/altdns

Step 5: Verify that the repository has been downloaded.

ls

Step 6: Navigate to the AltDNS directory.

cd altdns

Step 7: List the project files.

ls

Step 8: Create a Python Virtual Environment

Recent versions of Kali Linux restrict installing Python packages directly into the system environment (PEP 668). Create a virtual environment before installing the required dependencies.

Install the virtual environment package:

sudo apt update
sudo apt install python3-venv

Create a virtual environment:

python3 -m venv venv

Activate the virtual environment:

source venv/bin/activate

After activation, your terminal prompt will display (venv), indicating that the virtual environment is active.

Step 9: Install the required dependencies.

pip3 install-r requirements.txt

python3 altdns--help

Working with Altdns Tool - Generate and Resolve Subdomains

Step 1: Create the Input File

Create a new file named subdomains.txt:

nano subdomains.txt

Add the known subdomains. For example:

www.geeksforgeeks.org
mail.geeksforgeeks.org
blog.geeksforgeeks.org

Save the file by pressing Ctrl + O, Enter, and then Ctrl + X.

Step 2: Verify the Input File

Ensure that the file has been created successfully.

ls *.txt

You should see subdomains.txt listed. If it is not present, recreate the file before proceeding.

Step 3: Verify the Wordlist

Confirm that the permutation wordlist is available.

ls words.txt

Step 4: Generate and Resolve Subdomains

Run the following command to generate permutations and resolve valid subdomains.

python3 altdns -i subdomains.txt -o data_output.txt -w words.txt -r -s results_output.txt

Step 5: View the Generated Results

Display all generated permutations:

cat data_output.txt

Use Multiple Threads

Run the following command:

python3 altdns -i subdomains.txt -o data_output.txt -w words.txt -r -s results_output.txt -t 20

After the scan completes, verify the output files:

ls *.txt

View all generated subdomains:

cat data_output.txt

Note: Increasing the thread count improves scanning speed but may consume more system and network resources.

Altdns - Subdomain discovery through alterations and permutations