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bruteblock(8)		FreeBSD	System Manager's Manual		 bruteblock(8)

NAME
     bruteblock	-- utility to block bruteforce attacks

SYNOPSIS
     bruteblock	[-f configfile]	[-h]
     bruteblockd -t table [-s sleep] [-p pidfile] [-f] [-h]

DESCRIPTION
     Bruteblock	allows system administrators to	block various bruteforce at-
     tacks on UNIX services. The program analyzes system logs and adds at-
     tacker's IP address into ipfw2 table effectively blocking them.  Ad-
     dresses are automatically removed from the	table after specified amount
     of	time. Bruteblock uses regular expressions to parse logs, which pro-
     vides flexibility allowing	it to be used with almost any network service.
     Bruteblock	is written in pure C, doesn't use any external programs	and
     work with ipfw2 tables via	raw sockets API.

     Bruteblock	consists of two	binaries: bruteblock and bruteblockd.

   bruteblock
     bruteblock	is intended to be used in /etc/syslog.conf to pipe logs	into.
     It	does log analysis and adds attacker IP's into ipfw2 table. Along with
     address and mask, every entry in ipfw2 table has value field, which is
     used by bruteblock	to store expiration time as 32 bit UNIX	timestamp.

     The following command line	options	are available for bruteblock:

     -f	configfile
	     Specify path to config file

     -h	     Display help

   bruteblockd
     bruteblock	is a daemon, which checks ipfw2	table periodically and removes
     expired entries.

     The following command line	options	are available for bruteblockd:

     -t	table
	     Specify numer of ipfw2 table

     -s	sleep
	     Specify table check interval

     -p	pidfile
	     Specify location of the pid file

     -f	     Run the daemon in the foreground (do not daemonize)

     -h	     Display help

     Such design allows	to avoid any IPC use and to store entries for differ-
     ent services in one table.	Also makes it is easy for the administrator to
     get list of currently blocked addresses and edit the list if needed so.

CONFIGURATION FILE
     Configuration file	for bruteblock utility allows you to set following
     values:

     regexp  regular expression	in perl-compatible format that is used to ex-
	     tract failed password attempts from log files.

     max_count,	within_time
	     defines time interval and maximum number of failed	password at-
	     tempts during that	interval. If the number	is exceeded by spe-
	     cific IP, that IP is blocked.

     reset_ip
	     time-to-live of table entry. When it expires, address is removed
	     from the table, thus being	unblocked.

     ipfw2_table_no
	     number of ipfw2 table to add bad IPs to. Must match -t parameter
	     of	bruteblockd.

EXAMPLE	(SSH)
     First, you	need to	establish log processing to determine attacker's IPs
     and add them to ipfw2 table.  Edit	/etc/syslog.conf and add the following
     entry:

     auth.info;authpriv.info | exec /usr/local/sbin/bruteblock -f /usr/local/etc/bruteblock/ssh.conf

     then restart syslogd.

     Next, you'll want to setup	periodical cleanup of ipfw2 table.  Add	fol-
     lowing lines to /etc/rc.conf:

     bruteblockd_enable="YES"
     bruteblockd_table="1"
     bruteblockd_flags="-s 5"

     don't forget to change table number and sleep interval to match your
     needs.

     Now launch	bruteblockd: /usr/local/etc/rc.d/bruteblockd.sh	start

     Finally, setup your ipfw to block addresses contained in the table:

     ipfw add 100 deny ip from me to table\(1\)
     ipfw add 100 deny ip from table\(1\) to me

     you may want to add these lines to	you /etc/rc.firewall.

SYSTEM REQUIREMENTS
     Bruteblock	requires FreeBSD 5.3 and above (tested on FreeBSD 5.3, 5.4,
     6.1) with ipfw2 firewall.

SEE ALSO
     ipfw(8), rc.conf(5), syslog.conf(5)

AUTHOR
     Alex Samorukov <samm@os2.kiev.ua>,	http://samm.kiev.ua/bruteblock/

FreeBSD				 July 31, 2006			       FreeBSD

NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION FILE | EXAMPLE (SSH) | SYSTEM REQUIREMENTS | SEE ALSO | AUTHOR

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