Commit Graph

97 Commits

Author SHA1 Message Date
5c39f1abd8
roles/common: minor changes to Debian sshd_config files 2023-08-10 22:10:04 +02:00
6794eb0432
roles/common: default to disabling SSH passwords 2023-08-10 22:09:03 +02:00
d280859b0d
roles/common: minor updates to Debian 11 sshd_config 2023-08-09 21:55:04 +02:00
4fa82faf18
roles/common: adjust sshd_config for Debian 12
Adjust sshd_config based on ssh-audit profile for OpenSSH 9.2.
2023-08-09 21:27:19 +02:00
b8f0b4b1fb
roles/common: add vanilla sshd_config for Debian 12 2023-08-09 21:16:50 +02:00
34be0013b7
Remove Debian 10 support 2022-09-11 09:21:08 +03:00
0240897b1b
Remove Ubuntu 18.04 support 2022-09-10 23:30:04 +03:00
0ffb1b1a36
roles/common: use pyinotify backend for nginx fail2ban jail
This seems to be automatically selected, but on some other servers
I notice it is not. I will set it here explicitly so fail2ban does
not fall back to the inefficient "polling" or incorrect "systemd"
backends.
2022-01-04 15:10:02 +02:00
b13ead0657
roles/common: use a range for mosh ports in nftables
This is better than a loop in Jinja (though that is useful!).
2021-09-28 07:34:25 +03:00
65e6dd34cd
roles/common: Add missing section to Debian 11 sshd_config
We need to be able to configure the list of SSH users.
2021-09-27 12:59:27 +03:00
575a9fdfe6
roles/common: Add mosh ports to common
These have been in each hosts's "extra" rules lists forever and I
use them on every single host so they might as well be in the base
rules.
2021-09-05 16:23:42 +03:00
98cc3a8c2e
Add nginx filter for fail2ban
Some hosts can use fail2ban's nginx-botsearch filter to ban anyone
making requests to non-existent files like wp-login.php. There is
no reason to request such files naively and anyone found doing so
can be banned immediately.

In theory I should report them to AbuseIPDB.com, but that will take
a little more wiring up.
2021-08-01 09:56:43 +03:00
a67d901641
roles/common: Use AbuseIPDB.com list in nftables
For now I am still manually updating this, as we can only hit their
API five times per day, so it is not possible to have each host get
the list themselves every day with our one API key.
2021-07-31 21:46:50 +03:00
7ae100faeb
roles/common: Add comments to nftables.conf 2021-07-30 09:37:30 +03:00
8dd7663b3c
roles/common: Use Abuse.ch's SSL Blacklist in nftables
This adds Abuse.sh's list of IPs using blacklisted SSL certificates
to nftables. These IPs are high confidence indicators of compromise
and we should not route them. The list is updated daily by a systemd
timer.

See: https://sslbl.abuse.ch/blacklist/
2021-07-29 10:16:00 +03:00
b66c724109
roles/common: Use nftables on Ubuntu 20.04 as well
This mostly copies the Debian 11 nftables setup and includes a play
to clean up the old firewalld settings, timers, etc.
2021-07-28 14:18:41 +03:00
8bc2b6f493
roles/common: Retab nftables.conf.j2 2021-07-27 22:03:23 +03:00
d3922e7878
roles/common: Port configurable firewall logic to nftables
This opens TCP port 22 on all hosts, TCP ports 80 and 443 on hosts
in the web group, and allows configuration of "extra" rules in the
host or group vars.
2021-07-27 21:22:32 +03:00
14814aa5d9
roles/common: Wire up fail2ban
The nftables support works easily and creates the table, chains, and
sets on demand.
2021-07-26 22:07:31 +03:00
3b053167b1
roles/common: Fix sources.list for Debian 11 Bullseye
Seems the path to the security updates repo changed.
2021-07-26 21:12:05 +03:00
9bba0d96bb
roles/common: Add initial support for nftables on Debian 11
I will try using nftables directly instead of via firewalld as of
Debian 11 as it is the replacement for the iptables/ipset stack in
recent years and is easier to work with.

This also includes a systemd service, timer, and script to update
the spamhaus DROP lists as nftables sets.

Still need to add fail2ban support.
2021-07-26 13:09:41 +03:00
0bad75788d
roles/common: Add encryption settings to Debian 11 sshd_config
Mostly based on the ssh-audit policy for OpenSSH 8.4, but with any
algorithms using less than 256 bits removed. NSA's Suite B removed
these long ago, and the new CNSA suite only uses 256 and up.

See: https://github.com/jtesta/ssh-audit/blob/master/src/ssh_audit/policy.py
See: https://en.wikipedia.org/wiki/Commercial_National_Security_Algorithm_Suite
2021-07-24 22:28:59 +03:00
892033b880
roles/common: port common settings to Debian 11 sshd_config
Still need to add the encryption settings.
2021-07-22 14:16:20 +03:00
7c6ab2a652 roles/common: Add sshd_config from Debian 11 RC2 2021-07-22 14:15:00 +03:00
1c95c1faa8
roles/common: Update KexAlgorithms in Ubuntu 20.04 sshd_config
Recommended by ssh-audit. Note that curve25519-sha256 is the new name
for the previously private implementation in libssh.
2021-07-22 12:57:31 +03:00
9ea14de6f5
roles/common: Remove Encrypt-and-MAC modes from Ubuntu 20.04 sshd_config
Recommended by ssh-audit, but also generally the concensus for a few
years that Encrypt-and-MAC is hard to get right. OpenSSH has several
Encrypt-then-MAC schemes available so we can use those.

See: https://www.daemonology.net/blog/2009-06-24-encrypt-then-mac.html
2021-07-22 12:48:12 +03:00
d7c34a30a3
roles/common: Add Spamhaus DROP lists to firewalld ipsets
This configures the recommended DROP, EDROP, and DROPv6 lists from
Spamhaus as ipsets in firewalld. First we copy an empty placeholder
ipset to seed firewalld, then we use a shell script to download the
real lists and activate them. The same shell script is run daily as
a service (update-spamhaus-lists.service) by a systemd timer.

I am strictly avoiding any direct ipset commands here because I want
to make sure that this works on older hosts where ipsets is used as
well as newer hosts that have moved to nftables such as Ubuntu 20.04.
So far I have tested this on Ubuntu 16.04, 18.04, and 20.04, but ev-
entually I need to abstract the tasks and run them on CentOS 7+ as
well.

See: https://www.spamhaus.org/drop/
2021-07-21 09:34:51 +03:00
4edf92fe0d
roles/common: Allow adding extra SSH users 2020-12-08 23:15:51 +02:00
72b8b193b5
Remove support for Debian 9 and Ubuntu 16.04 2020-07-14 09:45:33 +03:00
539f081d4d
roles/common: Remove storage-specific tweaks
We don't have any "storage" group. This was ported from somewhere
else and I didn't notice that code.
2020-07-14 09:10:07 +03:00
6fcb1290fe roles/common: Port sshd_config changes from Debian 10 to Ubuntu 20.04
By now the recommendations we were using as guidance are five years
old. The ciphers have not changed much since then.
2020-06-08 12:15:29 +03:00
5a58d93dfe roles/common: Import sshd_config for Ubuntu 20.04 2020-06-08 12:15:29 +03:00
870bdbfcc3 roles/common: Harden fail2ban service on Ubuntu 20.04 2020-06-08 12:15:29 +03:00
2dc195b33c
Use version() instad of version_compare()
This changed in Ansible 2.5 apparently.

See: https://docs.ansible.com/ansible/latest/user_guide/playbooks_tests.html
2020-03-09 15:20:51 +02:00
d8d8a01a5f
roles/common: Remove SSH rate limiting from firewalld
Rather than a simple rate limit, I'm now using fail2ban to ban IPs
that actually fail to login.
2019-10-26 16:41:42 +02:00
0605f70f2e
roles/common: Add support for fail2ban
This is active banning of IPs that are brute forcing login attempts
to SSH, versus the passive banning of 10,000 abusive IPs from the
abuseipdb.com blacklist. For now I am banning IPs that fail to log
in successfully more than twelve times in a one-hour period, but
these settings might change, and I can override them at the group
and host level if needed.

Currently this works for CentOS 7, Ubuntu 16.04, and Ubuntu 18.04,
with minor differences in the systemd configuration due to older
versions on some distributions.

You can see the status of the jail like this:

    # fail2ban-client status sshd
    Status for the jail: sshd
    |- Filter
    |  |- Currently failed: 0
    |  |- Total failed:     0
    |  `- Journal matches:  _SYSTEMD_UNIT=sshd.service + _COMM=sshd
    `- Actions
       |- Currently banned: 1
       |- Total banned:     1
       `- Banned IP list:   106.13.112.20

You can unban IPs like this:

    # fail2ban-client set sshd unbanip 106.13.112.20
2019-10-26 16:36:07 +02:00
f3614d4ad4
roles/common: Remove buster-backports
I was using it to get iptables 1.8.3 to work around an issue with
firewalld, but I've solved that another way.
2019-10-18 22:56:52 +03:00
d030827f12
roles/common: Relax SSH rate limit in firewalld
Now that I'm blocking ~10,000 malicious IPs from AbuseIPDB I feel
more comfortable using a more relaxed rate limit for SSH. A limit
of 12 per minute is about one every five seconds.
2019-10-06 18:27:45 +03:00
6ebf900960
roles/common: Add missing rules for abusers ipsets
I had forgotten to add these when porting these rules from another
repository.
2019-10-05 13:01:51 +03:00
2740f050fc
roles/common: Increase ssh MaxAuthTries from 3 to 4
If a user has RSA, ECDSA, and ED25519 private keys present on their
system then the ssh client will offer all of these to the server
and they may not get a chance to try password auth before it fails.
2019-09-15 15:17:00 +03:00
cf16264f53
roles/common: Update sshd_config template for Debian 10
It seems I had imported the stock one from a default install, but I
never configured it.
2019-09-15 15:15:30 +03:00
43715dd392
roles/common: Use stable tarsnap 2019-09-13 22:14:49 +03:00
7551b803f6
roles/common: Use iptables 1.8.3 on Debian Buster
There is a bug in iptables 1.8.2 in Debian 10 "Buster" that causes
firewalld to fail when restoring rules. The bug has been fixed in
iptables 1.8.3, which is currently in buster-backports.

See: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914694
2019-08-01 15:36:15 +03:00
c148da73e7
roles/common: Use experimental Tarsnap on Debian buster
Tarsnap currently provides experimental packages for Debian Buster.

See: https://www.tarsnap.com/pkg-deb.html#experimental
2019-07-19 12:07:27 +03:00
39622077cd roles/common: Use Debian 9 tarsnap packages
There are no tarsnap binaries for Debian 10 yet.
2019-07-06 21:16:19 +03:00
b79001f97a roles/common: Update security.sources.list for cron-apt
We need to make sure to get security updates for packages that are
not in main!
2019-07-06 21:16:19 +03:00
207296b1f8 roles/common: Update Debian security apt repository
See: https://www.debian.org/security/
2019-07-06 21:16:19 +03:00
dd5662911e roles/common: Import sshd_config from Debian 10
OpenSSH version is 7.9p1-10.
2019-07-06 21:16:19 +03:00
18ee583261
roles/common: Don't log brute force SSH attempts
This is nice to see that the throttling is working, but the logs are
completely full of this useless crap now.
2019-02-26 10:30:03 -08:00
329edaee87
roles/common: Rate limit SSH connections in firewalld
I think 5 connections per minute is more than enough. Any over this
and it will be logged to the systemd journal as a warning.

See: https://www.win.tue.nl/~vincenth/ssh_rate_limit_firewalld.htm
See: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/security_guide/configuring_complex_firewall_rules_with_the_rich-language_syntax
2019-01-28 14:09:18 +02:00