fail2ban/config/filter.d/sshd-ddos.conf

# Fail2Ban ssh filter for at attempted exploit
#
# The regex here also relates to a exploit:
#
#  http://www.securityfocus.com/bid/17958/exploit
#  The example code here shows the pushing of the exploit straight after
#  reading the server version. This is where the client version string normally
#  pushed. As such the server will read this unparsible information as
#  "Did not receive identification string".

[INCLUDES]

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

[Definition]

_daemon = sshd

failregex = ^%(__prefix_line)sDid not receive identification string from <HOST>\s*$

ignoreregex = 

[Init]

journalmatch = _SYSTEMD_UNIT=sshd.service + _COMM=sshd

# Author: Yaroslav Halchenko