J
J
junior_css2021-09-22 00:44:06
SSH
junior_css, 2021-09-22 00:44:06

How to set up fail2ban + ipset blocking?

Hello. There is a debian 10 axis, Vesta panel is installed on it.
And additionally fail2ban
I constantly see how in Iptables, huge block lists are added, bots brute port 22.
Changing the port in this situation is not of interest, the question is how to set blocking in the configuration file immediately in ipset?
In order not to hammer iptables

Current config:

[ssh-iptables]
enabled  = true
filter   = sshd
action   = vesta[name=SSH]
logpath  = /var/log/auth.log
maxretry = 3


sshd.conf

# Fail2Ban filter for openssh
#
# If you want to protect OpenSSH from being bruteforced by password
# authentication then get public key authentication working before disabling
# PasswordAuthentication in sshd_config.
#
#
# "Connection from <HOST> port \d+" requires LogLevel VERBOSE in sshd_config
#

[INCLUDES]

# Read common prefixes. If any customizations available -- read them from
# common.local
before = common.conf

[DEFAULT]

_daemon = sshd

# optional prefix (logged from several ssh versions) like "error: ", "error: PAM: " or "fatal: "
__pref = (?:(?:error|fatal): (?:PAM: )?)?
# optional suffix (logged from several ssh versions) like " [preauth]"
__suff = (?: \[preauth\])?\s*
__on_port_opt = (?: port \d+)?(?: on \S+(?: port \d+)?)?

# for all possible (also future) forms of "no matching (cipher|mac|MAC|compression method|key exchange method|host key type) found",
# see ssherr.c for all possible SSH_ERR_..._ALG_MATCH errors.
__alg_match = (?:(?:\w+ (?!found\b)){0,2}\w+)

[Definition]

prefregex = ^<F-MLFID>%(__prefix_line)s</F-MLFID>%(__pref)s<F-CONTENT>.+</F-CONTENT>$

cmnfailre = ^[aA]uthentication (?:failure|error|failed) for <F-USER>.*</F-USER> from <HOST>( via \S+)?\s*%(__suff)s$
            ^User not known to the underlying authentication module for <F-USER>.*</F-USER> from <HOST>\s*%(__suff)s$
            ^Failed \S+ for invalid user <F-USER>(?P<cond_user>\S+)|(?:(?! from ).)*?</F-USER> from <HOST>%(__on_port_opt)s(?: ssh\d*)?(?(cond_user): |(?:(?:(?! from ).)*)$)
            ^Failed \b(?!publickey)\S+ for (?P<cond_inv>invalid user )?<F-USER>(?P<cond_user>\S+)|(?(cond_inv)(?:(?! from ).)*?|[^:]+)</F-USER> from <HOST>%(__on_port_opt)s(?: ssh\d*)?(?(cond_user): |(?:(?:(?! from ).)*)$)
            ^<F-USER>ROOT</F-USER> LOGIN REFUSED.* FROM <HOST>\s*%(__suff)s$
            ^[iI](?:llegal|nvalid) user <F-USER>.*?</F-USER> from <HOST>%(__on_port_opt)s\s*$
            ^User <F-USER>.+</F-USER> from <HOST> not allowed because not listed in AllowUsers\s*%(__suff)s$
            ^User <F-USER>.+</F-USER> from <HOST> not allowed because listed in DenyUsers\s*%(__suff)s$
            ^User <F-USER>.+</F-USER> from <HOST> not allowed because not in any group\s*%(__suff)s$
            ^refused connect from \S+ \(<HOST>\)\s*%(__suff)s$
            ^Received <F-MLFFORGET>disconnect</F-MLFFORGET> from <HOST>%(__on_port_opt)s:\s*3: .*: Auth fail%(__suff)s$
            ^User <F-USER>.+</F-USER> from <HOST> not allowed because a group is listed in DenyGroups\s*%(__suff)s$
            ^User <F-USER>.+</F-USER> from <HOST> not allowed because none of user's groups are listed in AllowGroups\s*%(__suff)s$
            ^pam_unix\(sshd:auth\):\s+authentication failure;\s*logname=\S*\s*uid=\d*\s*euid=\d*\s*tty=\S*\s*ruser=<F-USER>\S*</F-USER>\s*rhost=<HOST>\s.*%(__suff)s$
            ^(error: )?maximum authentication attempts exceeded for <F-USER>.*</F-USER> from <HOST>%(__on_port_opt)s(?: ssh\d*)?%(__suff)s$
            ^User <F-USER>.+</F-USER> not allowed because account is locked%(__suff)s
            ^<F-MLFFORGET>Disconnecting</F-MLFFORGET>: Too many authentication failures(?: for <F-USER>.+?</F-USER>)?%(__suff)s
            ^<F-NOFAIL>Received <F-MLFFORGET>disconnect</F-MLFFORGET></F-NOFAIL> from <HOST>: 11:
            ^<F-NOFAIL>Connection <F-MLFFORGET>closed</F-MLFFORGET></F-NOFAIL> by <HOST>%(__suff)s$
            ^<F-MLFFORGET><F-NOFAIL>Accepted publickey</F-NOFAIL></F-MLFFORGET> for \S+ from <HOST>(?:\s|$)

mdre-normal =

mdre-ddos = ^Did not receive identification string from <HOST>%(__suff)s$
            ^Connection <F-MLFFORGET>reset</F-MLFFORGET> by <HOST>%(__on_port_opt)s%(__suff)s
            ^<F-NOFAIL>SSH: Server;Ltype:</F-NOFAIL> (?:Authname|Version|Kex);Remote: <HOST>-\d+;[A-Z]\w+:
            ^Read from socket failed: Connection <F-MLFFORGET>reset</F-MLFFORGET> by peer%(__suff)s

mdre-extra = ^Received <F-MLFFORGET>disconnect</F-MLFFORGET> from <HOST>%(__on_port_opt)s:\s*14: No supported authentication methods available%(__suff)s$
            ^Unable to negotiate with <HOST>%(__on_port_opt)s: no matching <__alg_match> found.
            ^Unable to negotiate a <__alg_match>%(__suff)s$
            ^no matching <__alg_match> found:

mdre-aggressive = %(mdre-ddos)s
                  %(mdre-extra)s

cfooterre = ^<F-NOFAIL>Connection from</F-NOFAIL> <HOST>

failregex = %(cmnfailre)s
            <mdre-<mode>>
            %(cfooterre)s

# Parameter "mode": normal (default), ddos, extra or aggressive (combines all)
# Usage example (for jail.local):
#   [sshd]
#   mode = extra
#   # or another jail (rewrite filter parameters of jail):
#   [sshd-aggressive]
#   filter = sshd[mode=aggressive]
#
mode = normal

#filter = sshd[mode=aggressive]

ignoreregex = 

maxlines = 1

journalmatch = _SYSTEMD_UNIT=sshd.service + _COMM=sshd

datepattern = {^LN-BEG}

# DEV Notes:
#
#   "Failed \S+ for .*? from <HOST>..." failregex uses non-greedy catch-all because
#   it is coming before use of <HOST> which is not hard-anchored at the end as well,
#   and later catch-all's could contain user-provided input, which need to be greedily
#   matched away first.
#
# Author: Cyril Jaquier, Yaroslav Halchenko, Petr Voralek, Daniel Black and Sergey Brester aka sebres
# Rewritten using prefregex (and introduced "mode" parameter) by Serg G. Brester.

Answer the question

In order to leave comments, you need to log in

1 answer(s)
A
Andrey Barbolin, 2021-09-22
@Example

There is already a ready preset in fail2ban 0.9.6

[ssh-iptables-ipset4]

enabled  = false
port     = ssh
filter   = sshd
banaction = iptables-ipset-proto4
logpath  = /var/log/sshd.log
maxretry = 6

Didn't find what you were looking for?

Ask your question

Ask a Question

731 491 924 answers to any question