I am running fail2ban (0.9.6-2) on Debian 9 with busybox-syslogd logging to /var/log/auth.log
setup with the following line in /etc/rc.local to get logs written to file.
/sbin/syslogd -O /var/log/auth.log || exit 1
SSHD jail is enabled but does not see failed login attempts
running fail2ban-regex on the auth.log file with the sshd filter gives no fails.
sshd_config set to AUTHPRIV and VERBOSE
Here is a sample of auth.log logs:
Jan 14 17:12:41 Fire-Video authpriv.info sshd(2556): Failed none for video from 192.168.60.5 port 56068 ssh2
Jan 14 17:12:42 Fire-Video authpriv.info sshd(2556): Failed password for video from 192.168.60.5 port 56068 ssh2
Jan 14 17:12:42 Fire-Video authpriv.info sshd(2556): Failed password for video from 192.168.60.5 port 56068 ssh2
Jan 14 17:12:42 Fire-Video authpriv.info sshd(2556): Connection closed by 192.168.60.5 port 56068 (preauth)
Jan 14 17:12:49 Fire-Video authpriv.info sshd(2558): Connection from 192.168.60.5 port 56074 on 192.168.40.19 port 22
Jan 14 17:12:53 Fire-Video authpriv.debug sshd(2558): pam_usermapper(sshd:auth): pam_sm_authenticate flags: 00000001
Jan 14 17:12:53 Fire-Video authpriv.notice sshd(2558): pam_usermapper(sshd:auth): aliasing to 'root'
Jan 14 17:12:53 Fire-Video authpriv.notice sshd(2558): pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=192.168.60.5 user=root
Jan 14 17:12:55 Fire-Video authpriv.info sshd(2558): Failed password for video from 192.168.60.5 port 56074 ssh2
Jan 14 17:13:15 Fire-Video authpriv.debug sshd(2558): pam_usermapper(sshd:auth): pam_sm_authenticate flags: 00000001
Jan 14 17:13:16 Fire-Video authpriv.info sshd(2558): Failed password for video from 192.168.60.5 port 56074 ssh2
Jan 14 17:13:21 Fire-Video authpriv.debug sshd(2558): pam_usermapper(sshd:auth): pam_sm_authenticate flags: 00000001
Jan 14 17:13:21 Fire-Video authpriv.info sshd(2558): Accepted password for video from 192.168.60.5 port 56074 ssh2
Jan 14 17:13:21 Fire-Video authpriv.info sshd(2558): pam_unix(sshd:session): session opened for user root by (uid=0)
This is my sshd.conf in filter.d
# 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
(Definition)
_daemon = sshd
failregex = ^%(__prefix_line)s(?:error: PAM: )?(aA)uthentication (?:failure|error|failed) for .* from <HOST>( via S+)?s*$
^%(__prefix_line)s(?:error: PAM: )?User not known to the underlying authentication module for .* from <HOST>s*$
^%(__prefix_line)sFailed S+ for (?P<cond_inv>invalid user )?(?P<user>(?P<cond_user>S+)|(?(cond_inv)(?:(?! from ).)*?|(^:)+)) from <HOST>(?: port d+)?(?: sshd*)?(?(cond_user):|(?:(?:(?! from ).)*)$)
^%(__prefix_line)sROOT LOGIN REFUSED.* FROM <HOST>s*$
^%(__prefix_line)s(iI)(?:llegal|nvalid) user .*? from <HOST>(?: port d+)?s*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because not listed in AllowUserss*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because listed in DenyUserss*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because not in any groups*$
^%(__prefix_line)srefused connect from S+ (<HOST>)s*$
^%(__prefix_line)s(?:error: )?Received disconnect from <HOST>: 3: .*: Auth fail(?: (preauth))?$
^%(__prefix_line)sUser .+ from <HOST> not allowed because a group is listed in DenyGroupss*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because none of user's groups are listed in AllowGroupss*$
^(?P<__prefix>%(__prefix_line)s)User .+ not allowed because account is locked<SKIPLINES>(?P=__prefix)(?:error: )?Received disconnect from <HOST>: 11: .+ (preauth)$
^(?P<__prefix>%(__prefix_line)s)Disconnecting: Too many authentication failures for .+? (preauth)<SKIPLINES>(?P=__prefix)(?:error: )?Connection closed by <HOST> (preauth)$
^(?P<__prefix>%(__prefix_line)s)Connection from <HOST> port d+(?: on S+ port d+)?<SKIPLINES>(?P=__prefix)Disconnecting: Too many authentication failures for .+? (preauth)$
^%(__prefix_line)s(error: )?maximum authentication attempts exceeded for .* from <HOST>(?: port d*)?(?: sshd*)? (preauth)$
^%(__prefix_line)spam_unix(sshd:auth):s+authentication failure;s*logname=S*s*uid=d*s*euid=d*s*tty=S*s*ruser=S*s*rhost=<HOST>s.*$
ignoreregex =
(Init)
# "maxlines" is number of log lines to buffer for multi-line regex searches
maxlines = 10
journalmatch = _SYSTEMD_UNIT=sshd.service + _COMM=sshd
# 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