Logcheck enhancement needs a volunteer

To: Rene Mayrhofer <rene.mayrhofer@vianova.at>
Cc: Debian User List <debian-user@lists.debian.org>
Subject: Logcheck enhancement needs a volunteer
From: Francois Gouget <fgouget@free.fr>
Date: Thu, 26 Apr 2001 12:23:08 -0700 (PDT)
Message-id: <[🔎] Pine.LNX.4.21.0104261212530.386-100000@amboise.dolphin>
   Hi,


   Back in the days of logcheck 1.1.1-8 I was bitten by the ignore.d
bug. So I looked at the source of logcheck and it seemed to me that it
was pretty innefficient to do one grep per file in the ignore.xxx
directories. I also thought that it would be nice to factorize some code
between the different cases.
   So I started hacking away but then 1.1.1-9 came out, I installed it
and it solved my problem. Also I ran out of time to test my changes so
the new file was left rotting on my hard-drive.
   Unfortunately I still don't have time to look at it again. So I'm
sending this to you and the debian-user mailing list in the hope that
something can be salvaged from what I have done. Maybe this could be
made into a wishlist bug report. Do what you think is best.


--- cut here ---
#!/bin/sh
#
#	logcheck.sh: Log file checker
#	Written by Craig Rowland <crowland@psionic.com>
#
#	This file needs the program logtail.c to run
#
#	This script checks logs for unusual activity and blatant
#	attempts at hacking. All items are mailed to administrators
# 	for review. This script and the logtail.c program are based upon
#       the frequentcheck.sh script idea from the Gauntlet(tm) Firewall
#	(c)Trusted Information Systems Inc. The original authors are
#	Marcus J. Ranum and Fred Avolio.
#
#	Default search files are tuned towards the TIS Firewall toolkit
# 	the TCP Wrapper program. Custom daemons and reporting facilites
#	can be accounted for as well...read the rest of the script for
#	details.
#
#	Version Information
#
#	1.0 	9/29/96  -- Initial Release
#	1.01	11/01/96 -- Added working /tmp directory for symlink protection
#			    (Thanks Richard Bullington (rbulling@obscure.org)
#	1.1	1/03/97	 -- Made this script more portable for Sun's.
#		1/03/97	 -- Made this script work on HPUX
#               5/14/97  -- Added Digital OSF/1 logging support. Big thanks
#                           to Jay Vassos-Libove <libove@compgen.com> for
#                           his changes.
#
# Some changes have been made by Rene Mayrhofer for the Debian distribution.


# CONFIGURATION SECTION

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/ucb:/usr/local/bin

# Logcheck is pre-configured to work on most BSD like systems, however it
# is a rather dumb program and may need some help to work on other
# systems. Please check the following command paths to ensure they are
# correct.

# Person to send log activity to.

# Full path to logtail program.
# This program is required to run this script and comes with the package.

#-- changed to meet Debian's location of the package
LOGTAIL=/usr/sbin/logtail

# Full path to SECURED (non public writable) /tmp directory.
# Prevents Race condition and potential symlink problems. I highly
# recommend you do NOT make this a publically writable/readable directory.
# You would also be well advised to make sure all your system/cron scripts
# use this directory for their "scratch" area.

TMPDIR=/var/state/logcheck

# The 'grep' command. This command MUST support the
# '-i' '-v' and '-f' flags!! The GNU grep does this by default (that's
# good GNUs for you Linux/FreeBSD/BSDI people :) ). The Sun grep I'm told
# does not support these switches, but the 'egrep' command does (Thanks
# Jason <jason@mastaler.com> ). Since grep and egrep are usually the GNU
# variety on most systems (well most Linux, FreeBSD, BSDI, etc) and just
# hard links to each other we'll just specify egrep here. Change this if
# you get errors.

# Linux, FreeBSD, BSDI, Sun, HPUX, etc.
GREP=egrep

# The 'mail' command. Most systems this should be OK to leave as is.
# If your default mail command does not support the '-s' (subject) command
# line switch you will need to change this command one one that does.
# The only system I've seen this to be a problem on are HPUX boxes.
# Naturally, the HPUX is so superior to the rest of UNIX OS's that they
# feel they need to do everything differently to remind the rest that
# they are the best ;).

# Linux, FreeBSD, BSDI, Sun, etc.
MAIL=mail
# HPUX 10.x and others(?)
#MAIL=mailx
# Digital OSF/1, Irix
#MAIL=Mail

# File of known active hacking attack messages to look for.
# Only put messages in here if you are sure they won't cause
# false alarms. This is a rather generic way of checking for
# malicious activity and can be inaccurate unless you know
# what past hacking activity looks like. The default is to
# look for generic ISS probes (who the hell else looks for
# "WIZ" besides ISS?), and obvious sendmail attacks/probes.

HACKING_FILE=/etc/logcheck/logcheck.hacking
HACKING_DIR=/etc/logcheck/hacking.d

# File of security violation patterns to specifically look for.
# This file should contain keywords of information administrators should
# probably be aware of. May or may not cause false alarms sometimes.
# Generally, anything that is "negative" is put in this file. It may miss
# some items, but these will be caught by the next check. Move suspicious
# items into this file to have them reported regularly.

VIOLATIONS_FILE=/etc/logcheck/logcheck.violations
VIOLATIONS_DIR=/etc/logcheck/violations.d

# File that contains more complete sentences that have keywords from
# the violations file. These keywords are normal and are not cause for
# concern but could cause a false alarm. An example of this is the word
# "refused" which is often reported by sendmail if a message cannot be
# delivered or can be a more serious security violation of a system
# attaching to illegal ports. Obviously you would put the sendmail
# warning as part of this file. Use your judgement before putting words
# in here or you can miss really important events. The default is to leave
# this file with only a couple entries. DO NOT LEAVE THE FILE EMPTY. Some
# grep's will assume that an EMPTY file means a wildcard and will ignore
# everything! The basic configuration allows for the more frequent sendmail
# error.
#
# Again, be careful what you put in here and DO NOT LEAVE IT EMPTY!

VIOLATIONS_IGNORE_FILE=/etc/logcheck/logcheck.violations.ignore
VIOLATIONS_IGNORE_DIR=/etc/logcheck/violations.ignore.d

# This is the name of a file that contains patterns that we should
# ignore if found in a log file. If you have repeated false alarms
# or want specific errors ignored, you should put them in here.
# Once again, be as specific as possible, and go easy on the wildcards

IGNORE_FILE=/etc/logcheck/logcheck.ignore
IGNORE_DIR=/etc/logcheck/ignore.d

# The files are reported in the order of hacking, security
# violations, and unusual system events. Notice that this
# script uses the principle of "That which is not explicitely
# ignored is reported" in that the script will report all items
# that you do not tell it to ignore specificially. Be careful
# how you use wildcards in the logcheck.ignore file or you
# may miss important entries.

# Make sure we really did clean up from the last run.
# Also this ensures that people aren't trying to trick us into
# overwriting files that we aren't supposed to. This is still a race
# condition, but if you are in a temp directory that does not have
# generic luser access it is not a problem. Do not allow this program
# to write to a generic /tmp directory where others can watch and/or
# create files!!

# Shouldn't need to touch these...
HOSTNAME=`hostname`
DATE=`date +%m/%d/%y:%H.%M`

# This file should contain the list of logfiles to check
# Rene Mayrhofer, 2000-11-24
LOGLIST=/etc/logcheck/logcheck.logfiles

# Added sourcing of the config file by Rene Mayrhofer, 14.5.1999
. /etc/logcheck/logcheck.conf
SYSADMIN=$SENDMAILTO

umask 077
rm -f $TMPDIR/check.$$ $TMPDIR/checkoutput.$$ $TMPDIR/checkreport.$$
if [ -f $TMPDIR/check.$$ -o -f $TMPDIR/checkoutput.$$ -o -f $TMPDIR/checkreport.$$ ]; then
	echo "Log files exist in $TMPDIR directory that cannot be removed. This
may be an attempt to spoof the log checker." \
	| $MAIL -s "$HOSTNAME $DATE ACTIVE SYSTEM ATTACK!" $SYSADMIN
	exit 1
fi

# LOG FILE CONFIGURATION SECTION
# You might have to customize these entries depending on how
# you have syslogd configured. Be sure you check all relevant logs.
# The logtail utility is required to read and mark log files.
# See INSTALL for more information. Again, using one log file
# is preferred and is easier to manage. Be sure you know what the
# > and >> operators do before you change them. LOG FILES SHOULD
# ALWAYS BE chmod 600 OWNER root!!

# Generic and Linux Slackware 3.x
#$LOGTAIL /var/log/messages > $TMPDIR/check.$$

# Linux Red Hat Version 3.x, 4.x
#$LOGTAIL /var/log/messages > $TMPDIR/check.$$
#$LOGTAIL /var/log/syslog >> $TMPDIR/check.$$
#$LOGTAIL /var/log/auth.log >> $TMPDIR/check.$$
#$LOGTAIL /var/log/mail.log >> $TMPDIR/check.$$
#$LOGTAIL /var/log/daemon.log >> $TMPDIR/check.$$

# Debian systems with logcheck.logfiles file
# created by Rene Mayrhofer, 2000-11-24
for file in `/bin/cat $LOGLIST`; do
	$LOGTAIL $file $TMPDIR/offset.`basename $file`
done > $TMPDIR/check.$$

# FreeBSD 2.x
#$LOGTAIL /var/log/messages > $TMPDIR/check.$$
#$LOGTAIL /var/log/maillog >> $TMPDIR/check.$$

# BSDI 2.x
#$LOGTAIL /var/log/messages > $TMPDIR/check.$$
#$LOGTAIL /var/log/secure >> $TMPDIR/check.$$
#$LOGTAIL /var/log/maillog >> $TMPDIR/check.$$
#$LOGTAIL /var/log/ftp.log >> $TMPDIR/check.$$
# Un-comment out the line below if you are using BSDI 2.1
#$LOGTAIL /var/log/daemon.log >> $TMPDIR/check.$$

# SunOS, Sun Solaris 2.5
#$LOGTAIL /var/log/syslog > $TMPDIR/check.$$
#$LOGTAIL /var/adm/messages >> $TMPDIR/check.$$

# HPUX 10.x and others(?)
#$LOGTAIL /var/adm/syslog/syslog.log > $TMPDIR/check.$$

# Digital OSF/1
# OSF/1 - uses rotating log directory with date & time in name
#        LOGDIRS=`find /var/adm/syslog.dated/* -type d -prune -print`
#        LOGDIR=`ls -dtr1 $LOGDIRS | tail -1`
#        if [ ! -d "$LOGDIR" ]
#        then
#          echo "Can't identify current log directory." >> $TMPDIR/checkrepo$
#        else
#                $LOGTAIL  $LOGDIR/auth.log >> $TMPDIR/check.$$
#                $LOGTAIL  $LOGDIR/daemon.log >> $TMPDIR/check.$$
#                $LOGTAIL  $LOGDIR/kern.log >> $TMPDIR/check.$$
#                $LOGTAIL  $LOGDIR/lpr.log >> $TMPDIR/check.$$
#                $LOGTAIL  $LOGDIR/mail.log >> $TMPDIR/check.$$
#                $LOGTAIL  $LOGDIR/syslog.log >> $TMPDIR/check.$$
#                $LOGTAIL  $LOGDIR/user.log >> $TMPDIR/check.$$
#        fi
#


# END CONFIGURATION SECTION. YOU SHOULDN'T HAVE TO EDIT ANYTHING
# BELOW THIS LINE.

function make_pattern_file()
{
	pat_file="$1"
	pat_dir="$2"

	if [ -f $pat_file ]; then
		cat "$pat_file"
	fi
	if [ -d $pat_dir -a "`echo $pat_dir/*`" != "$pat_dir/*" ]; then
		cat $pat/*
	fi
}

function filter_log()
{
	src="$1"
	dst="$2"
	match="$3"
	ignore="$4"

	if [ ! -s $src ]; then
		return 0;
	fi
	if [ -n $match -a -s $match ]; then
		if [ -n $ignore -a -s $ignore ]; then
			$GREP -i -f $match $src | $GREP -v -f $ignore >$dst
		else
			$GREP -i -f $match $src >$dst
		fi
	elif [ -n $ignore -a -s $ignore]; then
		$GREP -v -f $ignore $src >$dst
	else
		ln -s $src $dst
	fi
	return test -s $dst
}


# Set the flag variables
FOUND=0
ATTACK=0

# See if the tmp file exists and actually has data to check,
# if it doesn't we should erase it and exit as our job is done.

if [ ! -s $TMPDIR/check.$$ ]; then
	rm -f $TMPDIR/check.$$
	exit 0
fi

# Perform Searches
# first sort the logs to remove duplicate lines (from different logfiles with
# the same lines) and reduce CPU and memory usage afterwards.
sort -u < $TMPDIR/check.$$ > $TMPDIR/check-sorted.$$
mv $TMPDIR/check-sorted.$$ $TMPDIR/check.$$

# Add an identification line at the beginning of the sent mail
# Rene Mayrhofer, 2000-11-24, text by Rainer Dorsch
echo "This mail is sent by logcheck. If you do not want to receive it any more," \
	>> $TMPDIR/checkreport.$$
echo "please modify the configuration files in /etc/logcheck or deinstall logcheck." \
	>> $TMPDIR/checkreport.$$

# Check for blatant hacking attempts
make_pattern_file "$HACKING_FILE" "$HACKING_DIR" >"$TMPDIR/pat_hack.$$"

if filter_log "$TMPDIR/check.$$" "$TMPDIR/checkoutput.$$" "$TMPDIR/pat_hack.$$"; then
	echo >> $TMPDIR/checkreport.$$
	echo "Active System Attack Alerts" >> $TMPDIR/checkreport.$$
	echo "=-=-=-=-=-=-=-=-=-=-=-=-=-=" >> $TMPDIR/checkreport.$$
	cat $TMPDIR/checkoutput.$$ >> $TMPDIR/checkreport.$$
	FOUND=1
	ATTACK=1
fi

# Check for security violations
make_pattern_file "$VIOLATIONS_FILE" "$VIOLATIONS_DIR" >"$TMPDIR/pat_violations.$$"
make_pattern_file "$VIOLATIONS_IGNORE_FILE" "$VIOLATIONS_IGNORE_DIR" >"$TMPDIR/pat_violations_ignore.$$"

if filter_log "$TMPDIR/check.$$" "$TMPDIR/checkoutput.$$" "$TMPDIR/pat_violations.$$" "$TMPDIR/pat_violations_ignore.$$"; then
	echo >> $TMPDIR/checkreport.$$
	echo "Security Violations" >> $TMPDIR/checkreport.$$
	echo "=-=-=-=-=-=-=-=-=-=" >> $TMPDIR/checkreport.$$
	cat $TMPDIR/checkoutput.$$ >> $TMPDIR/checkreport.$$
	FOUND=1
fi

# Do reverse grep on patterns we want to ignore
make_pattern_file "$IGNORE_FILE" "$IGNORE_DIR" >"$TMPDIR/pat_ignore.$$"

if filter_log "$TMPDIR/check.$$" "$TMPDIR/checkoutput.$$" "$TMPDIR/pat_ignore.$$"; then
	echo >> $TMPDIR/checkreport.$$
	echo "Unusual System Events" >> $TMPDIR/checkreport.$$
	echo "=-=-=-=-=-=-=-=-=-=-=" >> $TMPDIR/checkreport.$$
	cat $TMPDIR/checkoutput.$$ >> $TMPDIR/checkreport.$$
	FOUND=1
fi

# If there are results, mail them to sysadmin

if [ "$ATTACK" -eq 1 ]; then
	cat $TMPDIR/checkreport.$$ | $MAIL -s "$HOSTNAME $DATE ACTIVE SYSTEM ATTACK!" $SYSADMIN
elif [ "$FOUND" -eq 1 ]; then
	cat $TMPDIR/checkreport.$$ | $MAIL -s "$HOSTNAME $DATE system check" $SYSADMIN
fi

# Clean Up
rm -f $TMPDIR/check.$$ $TMPDIR/check-sorted.$$ $TMPDIR/checkoutput.$$ \
	$TMPDIR/checkoutput.tmp.$$ $TMPDIR/checkreport.$$ \
	$TMPDIR/pat_*
--- cut here ---

--
Francois Gouget         fgouget@free.fr        http://fgouget.free.fr/
                  Dieu dit: "M-x Lumière". Et la lumière fut.
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