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 brand impersonation. Useful as an additional source of targeted threat intelligence.
DNS fuzzing is an automated workflow for discovering potentially malicious domains targeting your organisation. This tool works by generating a large list of permutations based on a domain name you provide and then checking if any of those permutations are in use. 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!
In a hurry? Try it in your web browser: dnstwist.it
Key features
- Variety of highly effective domain fuzzing algorithms
- Unicode domain names (IDN)
- Additional domain permutations from dictionary files
- Efficient multithreaded task distribution
- Live phishing webpage detection:
- HTML similarity with fuzzy hashes (ssdeep)
- Screenshot visual similarity with perceptual hashes (pHash)
- Rogue MX host detection (intercepting misdirected e-mails)
- GeoIP location
- Export to CSV and JSON
Installation
Python PIP
$ pip install dnstwist[full]
Alternatively install the bare minimum and add other requirements manually depending on your needs:
$ 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 .
Debian/Ubuntu/Kali Linux
Invoke the following command to install the tool with all extra packages:
$ sudo apt install dnstwist
Fedora Linux
$ sudo dnf install dnstwist
macOS
This will install dnstwist along with all dependencies, and the binary will
be added to $PATH.
$ brew install dnstwist
Docker
Pull and run official image from the Docker Hub:
$ docker run -it elceef/dnstwist
Quick start guide
The tool will run the provided domain name through its fuzzing algorithms and generate a list of potential phishing domains along with DNS records.
Usually thousands of domain permutations are generated - especially for longer input domains. In such cases, it may be practical to display only the ones that are registered:
$ 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 or DNS-over-HTTPS server
with --nameservers argument.
Sometimes 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.
Note: Be aware of possible false positives. Some mail servers only pretend to accept incorrectly addressed e-mails but then discard those messages.
$ 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.
$ dnstwist --dictionary dictionaries/english.dict domain.name
If you need to check whether domains with different TLD exist, just supply a dictionary file with the list of TLD.
$ dnstwist --tld dictionaries/common_tlds.dict domain.name
On the other hand, if only selected algorithms need to be used, --fuzzers
argument is available, which takes a comma-separated list.
Note: non-existent algorithm names will be silently ignored.
$ dnstwist --fuzzers homoglyph,hyphenation domain.name
Apart from the colorful terminal output, the tool allows exporting results to
CSV and JSON. In case you need just the permutations without making any DNS
lookups, use --format list argument:
$ dnstwist --format csv domain.name | column -t -s,
$ dnstwist --format json domain.name | jq
$ dnstwist --format list domain.name
The tool can perform real-time lookups to return geographical location (approximated to the country) of IPv4 addresses.
$ dnstwist --geoip domain.name
The GeoIP2 library is used by default. Country database location has to be
specified with $GEOLITE2_MMDB environment variable. If the library or the
database are not present, the tool will fall-back to the older GeoIP Legacy.
To display all available options with brief descriptions simply execute the tool without any arguments.
Phishing detection
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, often called ssdeep) and perceptual hashes
(pHash). Fuzzy hashing is a concept that involves the ability to compare two
inputs (HTML code) and determine a fundamental level of similarity, while
perceptual hash is a fingerprint derived from visual features of an image
(web browser screenshot).
The unique feature of detecting similar HTML source code can be enabled with
--ssdeep argument. For each generated domain, dnstwist will fetch content
from responding HTTP server (following possible redirects), normalize HTML code
and compare its fuzzy hash with the one for the original (initial) domain. The
level of similarity will be expressed as a percentage.
Important: In cases when the effective URL is the same as for the original domain, the fuzzy hash is not calculated at all in order to reject false positive indications.
Note: Keep in mind it's rather unlikely to get 100% match, even for MITM attack frameworks, and that a phishing site can have completely different HTML source code. However, each notification is a strong indicator and 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. Use --ssdeep-url to override URL to
fetch the original web page from.
$ dnstwist --ssdeep https://domain.name/owa/
$ dnstwist --ssdeep --ssdeep-url https://different.domain/owa/ domain.name
Additionally, if Chromium browser is installed, dnstwist can run it in
headless mode to render web pages, take screenshots and calculate pHash to
evaluate visual similarity expressed as percentage.
$ dnstwist --phash domain.name
Web page screenshots in PNG format can be saved to specified location:
$ dnstwist --phash --screenshots /tmp/domain domain.name
API
In case you need to consume the data produced by the tool within your code, probably the most convenient and fast way is to pass the input as follows.
>>> import dnstwist
>>> data = dnstwist.run(domain='domain.name', registered=True, format='null')
The arguments for dnstwist.run() are translated internally, so the usage is
very similar to the command line. Keep in mind that dnstwist.run() spawns
a number of daemon threads.
Notes on coverage
Along with the length of the domain, the number of variants generated by the algorithms increases considerably, and therefore the time and resources needed to verify them. It's mathematically impossible to check all domain permutations - especially for longer input domains which would require millions of DNS lookups. 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.
Unicode tables consist of thousands of characters with many of them visually similar to each other. However, despite the fact certain characters are encodable using punycode, most TLD authorities will reject them during domain registration process. In general, TLD authorities disallow mixing of characters coming from different Unicode scripts or maintain their own sets of acceptable characters. With that being said, the homoglyph fuzzer was build on top of carefully researched range of Unicode characters (homoglyphs) to ensure that generated domains can be registered in practice.
It really works
The scanner is utilized by tens of SOC and incident response teams around the globe, as well as independent information security analysts and researchers. On top of this, it's integrated into products and services of many security providers, in particular but not only:
Splunk ESCU, RecordedFuture, SpiderFoot, DigitalShadows, SecurityRisk, SmartFense, ThreatPipes, PaloAlto Cortex XSOAR, Rapid7 InsightConnect SOAR, Mimecast, Watcher, Intel Owl, PatrOwl, VDA Labs, Appsecco, Conscia ThreatInsights.
Contact
To send questions, thoughts or a bar of chocolate, just drop an e-mail at marcin@ulikowski.pl. 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.