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Fail2Ban Setup
Setup Fail2ban will prevent attackers to brute force your vault logins. This is particularly important if your instance is publicaly available.
- Pre-requisite
- Installation
- Setup for web vault
- Setup for admin page
- Testing Fail2Ban
- SELinux Problems
- Commands below are using
vi
. The basics can be found there. However, you can use whatever text editor you want. - From Release 1.5.0, Bitwarden_rs supports logging to file. Please set this up : Logging
- Try to log to web vault with a false account and check the log files for 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.
sudo apt-get install fail2ban -y
EPEL repository is necessary (CentOS 7)
sudo yum install epel-release
sudo yum install fail2ban -y
With Synology, a bit more work is needed for various reasons. The full solution is pushed with Docker Compose there. The main issues are:
- The embedded IP ban system does not work for Docker's containers
- The iptables embedded do no support the
REJECT
blocktype - The Docker GUI does not allow some advanced settings
- Modifying system configuration is not upgrade-proof
Therefore, we will use Fail2ban in a Docker container. Crazy-max/docker-fail2ban provides a good solution and the Synology's Docker GUI will be ignored. From command line through SSH, here the steps. As a convention volumeX
is to be adapted to your Synology's config.
- Get root
sudo -i
- Creating persistent folders
mkdir -p /volumeX/docker/fail2ban/action.d/
mkdir -p /volumeX/docker/fail2ban/jail.d/
mkdir -p /volumeX/docker/fail2ban/filter.d/
- Replace
REJECT
byDROP
blocktype
vi /volumeX/docker/fail2ban/action.d/iptables-common.local
Copy and paste the following content
[Init]
blocktype = DROP
[Init?family=inet6]
blocktype = DROP
- Create docker-compose file
vi /volumeX/docker/fail2ban/docker-compose.yml
Copy and paste the following content
version: '3'
services:
fail2ban:
container_name: fail2ban
restart: always
image: crazymax/fail2ban:latest
environment:
- TZ=Europe/Paris
- F2B_DB_PURGE_AGE=30d
- F2B_LOG_TARGET=/data/fail2ban.log
- F2B_LOG_LEVEL=INFO
- F2B_IPTABLES_CHAIN=INPUT
volumes:
- /volumeX/docker/fail2ban:/data
- /volumeX/docker/bw-data:/bitwarden:ro
network_mode: "host"
privileged: true
cap_add:
- NET_ADMIN
- NET_RAW
- Start the container using command line
cd /volumeX/docker/fail2ban
docker-compose up -d
You should see the container running in Synology's Docker GUI. You will have to reload after configuring the filters and jails
As a convention, path_f2b
means the path needed for Fail2ban to work. This depends on your system. E.g. on Synology, we are talking about /volumeX/docker/fail2ban/
where on some other systems we are talking about /etc/fail2ban/
Create and fill the following file
vi path_f2b/filter.d/bitwarden_rs.local
Copy and paste the following content
[INCLUDES]
before = common.conf
[Definition]
failregex = ^.*Username or password is incorrect\. Try again\. IP: <ADDR>\. Username:.*$
ignoreregex =
Tip: If you get the following error message in fail2ban.log
(CentOS 7, Fail2Ban v0.9.7)
fail2ban.filter [5291]: ERROR No 'host' group in '^.*Username or password is incorrect\. Try again\. IP: <ADDR>\. Username:.*$'
Please Use <HOST>
instead of <ADDR>
in bitwarden_rs.local
Tip: If you see 127.0.0.1 as the IP address of failed logins in bitwarden.log, then you're probably using a reverse proxy and fail2ban won't work correctly:
[YYYY-MM-DD hh:mm:ss][bitwarden_rs::api::identity][ERROR] Username or password is incorrect. Try again. IP: 127.0.0.1. Username: email@example.com.
To remedy this, forward the true remote address to bitwarden_rs via the X-Real-IP header. How to do this varies depending on the proxy you use. For example, in Caddy 2.x, when you define the reverse-proxy, define header_up X-Real-IP {remote_host}
. See Proxy examples for more info.
Create and fill the following file
vi path_f2b/jail.d/bitwarden_rs.local
Copy and paste the following content
[bitwarden_rs]
enabled = true
port = 80,443,8081
filter = bitwarden_rs
banaction = %(banaction_allports)s
logpath = /path/to/bitwarden.log
maxretry = 3
bantime = 14400
findtime = 14400
Note: Docker uses the FORWARD chain instead of the default INPUT chain. Therefore replace the banaction
line with the following action
when using Docker:
action = iptables-allports[name=bitwarden_rs, 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!
NOTE on the NOTE above:
That's at least not true for running on Docker (CentOS 7) with caddy as reverse proxy. chain=FORWARD is absolutely fine and working with caddy as reverse proxy.
Reload fail2ban for changes to take effect:
sudo systemctl reload fail2ban
Feel free to change the options as you see fit.
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. The process is the same as for the web vault.
Create and fill the following file
vi path_f2b/filter.d/bitwarden-admin.local
Copy and paste the following content
[INCLUDES]
before = common.conf
[Definition]
failregex = ^.*Invalid admin token\. IP: <ADDR>.*$
ignoreregex =
Create and fill the following file
vi path_f2b/jail.d/bitwarden_rs-admin.local
Copy and paste the following content
[bitwarden_rs-admin]
enabled = true
port = 80,443
filter = bitwarden_rs-admin
banaction = %(banaction_allports)s
logpath = /path/to/bitwarden.log
maxretry = 3
bantime = 14400
findtime = 14400
Note: Docker uses the FORWARD chain instead of the default INPUT chain. Therefore replace the banaction
line with the following action
when using Docker:
action = iptables-allports[name=bitwarden_rs, chain=FORWARD]
Reload fail2ban for changes to take effect:
sudo systemctl reload fail2ban
Now just try to login to bitwarden using any email (it doesn't 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:
Without Docker:
sudo fail2ban-client set bitwarden_rs unbanip XX.XX.XX.XX
With Docker:
sudo docker exec -t fail2ban fail2ban-client set bitwarden_rs 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).
Also verify that the timezone of the Docker container matches the timezone of the host. Check this by comparing the time shown in the logfile with the host OS time. If they differ, there are various ways to fix this. One option is to start Docker with the option -e "TZ=<timezone>"
. A list of valid timezones is here (eg. -e "TZ=Australia/Melbourne"
)
If you are using podman instead of Docker it seems that setting the timezone via -e "TZ=<timezone>"
does not work. This can be solved (when using the alpine image) by following this guide: https://wiki.alpinelinux.org/wiki/Setting_the_timezone.
When you are using SELinux it is possible that SELinux hinders fail2ban to read the logs. If so, follow these steps:
sudo tail /var/log/audit/audit.log
. There you should see something along the lines of this (of course the actual audit ID will vary in your case):
type=AVC msg=audit(1571777936.719:2193): avc: denied { search } for pid=5853 comm="fail2ban-server" name="containers" dev="dm-0" ino=1144588 scontext=system_u:system_r:fail2ban_t:s0 tcontext=unconfined_u:object_r:container_var_lib_t:s0 tclass=dir permissive=0
To actually find out the reason you can use grep 'type=AVC msg=audit(1571777936.719:2193)' /var/log/audit/audit.log | audit2why
. audit2allow -a
will give you specific instructions on how to create a module and allow fail2ban to access these logs. Follow these steps and you're done! fail2ban should now work correctly.
- Which container image to use
- Starting a container
- Updating the vaultwarden image
- Using Docker Compose
- Using Podman
- Building your own docker image
- Building binary
- Pre-built binaries
- Third-party packages
- Deployment examples
- Proxy examples
- Logrotate example
- Overview
- Disable registration of new users
- Disable invitations
- Enabling admin page
- Disable the admin token
- Enabling WebSocket notifications
- Enabling Mobile Client push notification
- Enabling U2F and FIDO2 WebAuthn authentication
- Enabling YubiKey OTP authentication
- Changing persistent data location
- Changing the API request size limit
- Changing the number of workers
- SMTP configuration
- Translating the email templates
- Password hint display
- Disabling or overriding the Vault interface hosting
- Logging
- Creating a systemd service
- Syncing users from LDAP
- Using an alternate base dir (subdir/subpath)
- Other configuration