This python utility scans for vulnerability to the DROWN attack against TLS. It is distributed under the GPLv2 license, and includes a specific version of https://github.com/tintinweb/scapy-ssl_tls (which is also distributed under GPLv2) and https://github.com/hiviah/pyx509. We are grateful to both authors for providing these useful libraries.

This utility was written in an ad-hoc manner in order to identify only the most common vulnerable configurations. We emphasize that it cannot accurately detect all vulnerable servers, and no one should rely on it to confidently determine a particular server is not vulnerable.

In particular, the utility only detects SSLv2 support by a single port. DROWN is made worse by its cross-protocol nature, i.e. an HTTPS server that doesn't support SSLv2 may be vulnerable because it shares its public key with an SMTP server that does. This utility cannot detect this scenario, and we strongly recommend testing servers using our online scanner, at https://drownattack.com.

Likewise, it may also have false positives, i.e. it may indicate a server is vulnerable when it is in fact not.

Hubert Kario has also made different scanning scripts available here: https://mta.openssl.org/pipermail/openssl-dev/2016-March/005602.html

You need the packages listed below. This dependency list is unfortunately a work in progress. If you think you're missing a dependency, please read the instructions for other operating systems, and see if they might shed light on the issue. Pull requests clarifying the dependency list (and also general PRs) are welcome.

Some versions of this tool produce the following lines on startup:

Import Error - most likely due to missing pycrypto libraries - disabling crypto functionality
ImportError('cannot import name TLSHandshake',)

These lines do not prevent the tool from producing its results.

sudo apt-get install tcpdump python-enum python-pyasn1 scapy python-crypto

and also run

pip install scapy-ssl_tls

sudo yum install python-enum scapy python-crypto tcpdump

and also run pip install scapy-ssl_tls

sudo pip install enum pycrypto scapy pyasn1 scapy-ssl_tls

You may also need dnet as a dependency.

One user has graciously documented setting up the dependencies on a stripped-down installation of CentOS: nimia#17

docker build -t public-drown-scanner .
docker run -it public-drown-scanner localhost 443

python scanner.py localhost 443
...
python scanner.py localhost 587 -esmtp
...
python scanner.py localhost 143 -imap
...
python scanner.py localhost 25 -esmtp
...
python scanner.py localhost 110 -pop3
...
python scanner.py localhost 443 -bare