See what sort of trouble users can get in trying to type your domain name. Find lookalike domains that adversaries can use to attack you. Can detect typosquatters, phishing attacks, fraud, and corporate espionage. Useful as an additional source of targeted threat intelligence.

The idea is quite straightforward: with the original domain name as input, the tool generates a list of potentially malicious domains and then checks which are registered. Additionally, it can generate fuzzy hashes of the web pages to see if they are part of an ongoing phishing attack or brand impersonation, and much more!

• A wide range of efficient domain fuzzing algorithms
• Unicode domain names (IDN)
• Additional domain permutations using dictionary files
• Multithreaded job distribution
• Queries IPv4, IPv6, NS and MX records
• Evaluates web page similarity with fuzzy hashes to find live phishing sites
• Tests if MX host (mail server) can be used to intercept misdirected e-mails
• GeoIP location information
• Grabs HTTP and SMTP service banners
• WHOIS lookups for creation and modification date
• Output in CSV and JSON format

Python PIP

$ pip install dnstwist

Git

If you want to run the latest version of the code, you can install it from Git:

$ git clone https://github.com/elceef/dnstwist.git
$ cd dnstwist
$ pip install .

OSX

Installation is simplified thanks to Homebrew package:

$ brew install dnstwist

This will install dnstwist along with all dependencies, and the binary will be added to $PATH.

Docker

If you prefer Docker, you can pull and run official image from the Docker Hub:

$ docker run elceef/dnstwist

This tool is designed to run fine with just standard Python3 library. However, a couple of third-party packages are required to show its full potential.

Debian/Ubuntu/Kali Linux

If running Debian-based distribution, you can install all external libraries with just single command:

$ sudo apt install python3-dnspython python3-tld python3-geoip python3-whois \
python3-requests python3-ssdeep

Alternatively, you can use Python PIP. This can be done within a virtual environment to avoid conflicts with other installations. However, you will still need essential build tools and a couple of libraries installed.

$ sudo apt install libfuzzy-dev
$ pip3 install -r requirements.txt

The tool will run the provided domain name through its fuzzing algorithms and generate a list of potential phishing domains with the following DNS records: A, AAAA, NS and MX.

Usually thousands of domain permutations are generated - especially for longer input domains. In such cases, it may be practical to display only registered (resolvable) ones using --registered argument.

$ dnstwist --registered domain.name

Ensure your DNS server can handle thousands of requests within a short period of time. Otherwise, you can specify an external DNS server with --nameservers argument.

Manually checking each domain name in terms of serving a phishing site might be time-consuming. To address this, dnstwist makes use of so-called fuzzy hashes (context triggered piecewise hashes). Fuzzy hashing is a concept that involves the ability to compare two inputs (in this case HTML code) and determine a fundamental level of similarity. This unique feature of dnstwist can be enabled with --ssdeep argument. For each generated domain, dnstwist will fetch content from responding HTTP server (following possible redirects) and compare its fuzzy hash with the one for the original (initial) domain. The level of similarity will be expressed as a percentage.

Please keep in mind it's rather unlikely to get 100% match for a dynamically generated web page. However, each notification should be inspected carefully regardless of the score.

$ dnstwist --ssdeep domain.name

In some cases, phishing sites are served from a specific URL. If you provide a full or partial URL address as an argument, dnstwist will parse it and apply for each generated domain name variant. This is obviously useful only with the fuzzy hashing feature.

$ dnstwist --ssdeep https://domain.name/owa/
$ dnstwist --ssdeep domain.name/login

Very often attackers set up e-mail honey pots on phishing domains and wait for mistyped e-mails to arrive. In this scenario, attackers would configure their server to vacuum up all e-mail addressed to that domain, regardless of the user it was sent towards. Another dnstwist feature allows performing a simple test on each mail server (advertised through DNS MX record) to check which one can be used for such hostile intent. Suspicious servers will be flagged with SPYING-MX string.

Please be aware of possible false positives. Some mail servers only pretend to accept incorrectly addressed e-mails but then discard those messages. This technique is used to prevent "directory harvesting attack".

$ dnstwist --mxcheck domain.name

If domain permutations generated by the fuzzing algorithms are insufficient, please supply dnstwist with a dictionary file. Some dictionary samples with a list of the most common words used in phishing campaigns are included. Feel free to adapt it to your needs.

$ dnstwist --dictionary dictionaries/english.dict domain.name

If you need to check whether domains with different TLDs exist, you can use the --tld option. You'll need to supply the TLDs list in a text file. A sample file is provided.

$ dnstwist --tld dictionaries/common_tlds.dict example.com

Apart from the default nice and colorful text terminal output, the tool provides two well known and easy to parse output formats: CSV and JSON. Use it for convenient data interchange.

$ dnstwist --format csv domain.name > out.csv
$ dnstwist --format json domain.name > out.json

In case you want to chain dnstwist with other tools and you need only domain variants without performing any DNS lookups, you can use --format idle:

$ dnstwist --format idle domain.name | tr '\n' ','

The tool can perform real-time lookups to return geographical location of IPv4 addresses. Use --geoip option to display country name next to each address.

$ dnstwist --geoip domain.name

To display all available options with brief descriptions simply execute the tool without any arguments.

Happy hunting!

Along with the length of the domain, the number of variants generated by the algorithms increases considerably, and therefore the number of DNS queries needed to verify them. For example, to check all variants for google.com, you would have to send over 300k queries. For the domain facebook.com the number increases to over 5 million. How easy it is to guess it takes a lot of resources and most importantly even more time. For longer domains checking all is simply not feasible. For this reason, this tool generates and checks domains very close to the original one. Theoretically, these are the most attractive domains from the attacker's point of view. However, be aware that the imagination of the aggressors is unlimited.

To send questions, comments or a bar of chocolate, just drop an e-mail at marcin@ulikowski.pl

You can also reach the author via:

• Twitter: @elceef
• LinkedIn: Marcin Ulikowski

Any feedback is appreciated. If you have found some confirmed phishing domains or just like this tool, please don't hesitate and send a message. Thank you.