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Fail2Ban Setup

jonathanmmm edited this page May 3, 2019 · 9 revisions

As of release 1.5.0, bitwarden_rs supports logging to file. See Logging for information on how to set this up.

Logging Failed Login Attempts

After specifying the log file location, failed login attempts will appear in the logs in the following format:

[YYYY-MM-DD hh:mm:ss][bitwarden_rs::api::identity][ERROR] Username or password is incorrect. Try again. IP: XXX.XXX.XXX.XXX. Username: email@domain.com.

Install Fail2Ban (under Debian/Rasbian)

sudo apt-get install fail2ban -y

Fail2Ban Filter

Create the filter file

sudo nano /etc/fail2ban/filter.d/bitwarden.conf

And add the following

[INCLUDES]
before = common.conf

[Definition]
failregex = ^.*Username or password is incorrect\. Try again\. IP: <HOST>\. Username:.*$
ignoreregex =

Fail2Ban Jail

Now we need the jail, create the jail file

sudo nano /etc/fail2ban/jail.d/bitwarden.local

and add:

[bitwarden]
enabled = true
port = 80,443,8081
filter = bitwarden
action = iptables-allports[name=bitwarden]
logpath = /path/to/bitwarden/log
maxretry = 3
bantime = 14400
findtime = 14400

Note: Docker uses the FORWARD chain instead of the default INPUT chain. Therefore use the following action when using Docker:

action = iptables-allports[name=bitwarden, chain=FORWARD]

NOTE: Do not use this if you use a reverse proxy before docker container. If proxy, like apache2 or nginx is used, use the ports of the proxy and do not use chain=FORWARD, only when using Docker without proxy!

Feel free to change the options as you see fit.

Testing Fail2Ban

Now just try to login to bitwarden using any email (it doesnt have to be a valid email, just an email format) If it works correctly and your IP is banned, you can unban the ip by running:

sudo fail2ban-client set bitwarden unbanip XX.XX.XX.XX

If Fail2Ban does not appear to be functioning, verify that the path to the Bitwarden log file is correct. For Docker: If the specified log file is not being generated and/or updated, make sure the EXTENDED_LOGGING env variable is set to true (which is default) and that the path to the log file is the path inside the docker (when you use /bw-data/:/data/ the log file should be in /data/... to be outside the container).

Setting Up Fail2Ban for the Admin Page

If you've enabled the admin console by setting the ADMIN_TOKEN environment variable, you can prevent an attacker brute-forcing the admin token using Fail2Ban. Following the same process as for the web vault, create the following filter in /etc/fail2ban/filter.d/bitwarden-admin.conf:

[INCLUDES]
before = common.conf

[Definition]
failregex = ^.*Invalid admin token\. IP: <HOST>.*$
ignoreregex =

Then create the following jail configuration in /etc/fail2ban/jail.d/bitwarden-admin.local (note that this example uses the action directive for the Docker image--modify it if you're using the binary build):

[bitwarden-admin]
enabled = true
port = 80,443
filter = bitwarden-admin
action = iptables-allports[name=bitwarden, chain=FORWARD]
logpath = /path/to/bitwarden.log
maxretry = 5
bantime = 14400
findtime = 14400
``
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