Slackware Snort Installation Guide
Copyright (c) 2007 Jeffrey Denton
http://www.cochiselinux.org/files/slackware-snort-0.2.txt
Written by Jeffrey Denton <dentonj@gmail.com>
23 Sept 2007
Version - 0.2
This is written for:
$ cat /etc/slackware-version
Slackware 12.0.0
This document was originally based on the Snort Enterprise Install document by
Patrick Harper.
The following will be installed and/or configured:
Snort
Barnyard
BASE
Oinkmaster
MySQL
Apache with SSL
ModSecurity
OSSEC HIDS Server and Agent
LogWatch
NTOP
Stunnel
--{ Required Reading ]--
The Snort Users Manual - http://www.snort.org/docs/snort_htmanuals/htmanual_2615
/
The Snort FAQ - http://www.snort.org/docs/faq/3Q06/
Oinkmaster README - http://oinkmaster.sourceforge.net/readme.shtml
Oinkmaster FAQ - http://oinkmaster.sourceforge.net/docs.shtml
How to stop Snort alerts from being generated / how to (not) ignore traffic -
http://oinkmaster.sourceforge.net/avoiding_snort_alerts.txt
README files - located in the "doc" directory of the source code
--[ Resources ]--
Snort Website - http://www.snort.org
The Snort-users mailing list -
http://lists.sourceforge.net/lists/listinfo/snort-users
Snort Forums - http://www.snort.org/reg-bin/forums.cgi
Bleeding Edge Threats - http://www.bleedingthreats.net
Bleeding Sigs mailing list -
http://lists.bleedingthreats.net/cgi-bin/mailman/listinfo/bleeding-sigs
Base Forums - http://base.secureideas.net/support.php
OSSEC Users mailing list - http://www.ossec.net/ossec-list/
ModSecurity documentation - http://www.modsecurity.org/documentation/index.html
NTOP mailing list - http://listgateway.unipi.it/pipermail/ntop/
Safari Library (paid subscription required) - http://safari.oreilly.com
--[ Books ]--
Snort Intrusion Detection and Prevention Toolkit, by Jay Beale, Syngress
Publishing, February 2007, ISBN - 1597490997
The Tao of Network Security Monitoring, by Richard Bejtlich, Addison-Wesley,
July 2004, ISBN - 0321246772
Extrusion Detection, by Richard Bejtlich, Addison-Wesley, November 2005,
ISBN - 0321349962
--[ Bash Prompt ]--
In this document, the shell prompts are included as part of the commands
that I use. The current working directory is listed to prevent readers
from getting lost in the directory tree while commands are being run. I've
modified the default shell prompt for this document to list only the current
working directory without listing the entire path. I made the change to
minimize the number of lines in the guide that wrap from one line to the next.
If you would like to use the same shell prompt, change the following to:
root@darkstar:~# vi /etc/profile
PS1='\u@\h:\w\$ '
To:
PS1='\u@\h:\W\$ '
To have this change take effect, run the follow for each terminal:
root@darkstar:~# source /etc/profile
--[ Snort Installation ]--
Create a downloads and a src directory. The directories will be used to store
downloads and to compile source code.
dentonj@darkstar:~$ mkdir downloads src
dentonj@darkstar:~$ cd downloads
dentonj@darkstar:downloads$ wget http://www.snort.org/dl/current/snort-2.7.0
.1.tar.gz
dentonj@darkstar:downloads$ wget http://www.snort.org/dl/current/snort-2.7.0
.1.tar.gz.md5
dentonj@darkstar:downloads$ md5sum -c snort-2.7.0.1.tar.gz.md5
snort-2.7.0.1.tar.gz: OK
If this file does not exist, there is a more recent version of Snort available.
Check http://www.snort.org to determine which version of Snort is the latest.
If you would like to use the version of Snort listed above, replace the
"current" directory with "old". Using an older version of Snort is generally
not recommended.
dentonj@darkstar:downloads$ cd ../src
dentonj@darkstar:src$ gzip -cd ../downloads/snort-2.7.0.1.tar.gz | tar xf -
dentonj@darkstar:src$ cd snort-2.7.0.1
dentonj@darkstar:snort-2.7.0.1$ ./configure --enable-dynamicplugins
--enable-timestamps --enable-perfprofiling --enable-gre --with-mysql
If your network does not normally use GRE tunnels, you can remove the
"--enable-gre" option.
dentonj@darkstar:snort-2.7.0.1$ make
dentonj@darkstar:snort-2.7.0.1$ su
root@darkstar:snort-2.7.0.1# make install
Create a user account that Snort will use while running.
root@darkstar:snort-2.7.0.1# groupadd snort
root@darkstar:snort-2.7.0.1# useradd -g snort snort -s /bin/false
root@darkstar:snort-2.7.0.1# passwd -S snort
The newly created user account is locked by default. Setting the shell to
"/bin/false" is an extra precaution.
Create the directories that are going to be used by Snort:
root@darkstar:snort-2.7.0.1# mkdir -p /etc/snort/rules
root@darkstar:snort-2.7.0.1# mkdir -p /var/log/snort/archive
root@darkstar:snort-2.7.0.1# chown -R snort.snort /var/log/snort
Copy the configuration files to the configuration directory for Snort:
root@darkstar:snort-2.7.0.1# cd etc
root@darkstar:etc# cp * /etc/snort
Register as a user on http://www.snort.org. Then download the month old VRT
Certified Rules. The downloaded rules contained Shared Object rules that need
to be compiled. To compile the Shared Object rules, extract the download in
the Snort source code directory.
dentonj@darkstar:downloads$ ls snortrules-snapshot-CURRENT.tar.gz*
snortrules-snapshot-CURRENT.tar.gz
snortrules-snapshot-CURRENT.tar.gz.md5
dentonj@darkstar:downloads$ md5sum -c snortrules-snapshot-CURRENT.tar.gz.md5
snortrules-snapshot-CURRENT.tar.gz: OK
dentonj@darkstar:downloads$ cd ../src/snort-2.7.0.1
dentonj@darkstar:snort-2.7.0.1$ gzip -cd ../../downloads/snortrules-snapshot
-CURRENT.tar.gz | tar xf -
dentonj@darkstar:snort-2.7.0.1$ cd so_rules
dentonj@darkstar:so_rules$ make
dentonj@darkstar:so_rules$ cat *.rules > so.rules
dentonj@darkstar:so_rules$ su
root@darkstar:so_rules# cp so.rules /etc/snort/rules
root@darkstar:so_rules# mkdir /usr/local/lib/snort_dynamicrule
root@darkstar:so_rules# cp *.so /usr/local/lib/snort_dynamicrule
Configure Snort to use the Shared Object rules:
root@darkstar:so_rules# vi /etc/snort/snort.conf
dynamicdetection directory /usr/local/lib/snort_dynamicrule/
include $RULE_PATH/so.rules
Copy the rest of the rules to the rule configuration directory for Snort:
root@darkstar:so_rules# cd ../rules
root@darkstar:rules# cp * /etc/snort/rules
Bleeding Edge Threats provides Snort rules for the latest vulnerabilities and
computer security threats. Download the rules:
dentonj@darkstar:downloads$ wget http://www.bleedingthreats.net/rules/bleedi
ng.rules.tar.gz
dentonj@darkstar:downloads$ su -
root@darkstar:~# cd /etc/snort
root@darkstar:snort# gzip -cd /home/dentonj/downloads/bleeding.rules.tar.gz
| tar xf -
Configure Snort to use the Bleeding Edge Threats rules:
root@darkstar:snort# vi snort.conf
include $RULE_PATH/bleeding.conf
include $RULE_PATH/bleeding-attack_response.rules
#include $RULE_PATH/bleeding-botcc-BLOCK.rules
include $RULE_PATH/bleeding-botcc.excluded
include $RULE_PATH/bleeding-botcc.rules
#include $RULE_PATH/bleeding-compromised-BLOCK.rules
include $RULE_PATH/bleeding-compromised.rules
include $RULE_PATH/bleeding-dos.rules
#include $RULE_PATH/bleeding-drop-BLOCK.rules
#include $RULE_PATH/bleeding-drop.rules
#include $RULE_PATH/bleeding-dshield-BLOCK.rules
include $RULE_PATH/bleeding-dshield.rules
include $RULE_PATH/bleeding-exploit.rules
include $RULE_PATH/bleeding-game.rules
include $RULE_PATH/bleeding-inappropriate.rules
include $RULE_PATH/bleeding-malware.rules
include $RULE_PATH/bleeding-p2p.rules
include $RULE_PATH/bleeding-policy.rules
include $RULE_PATH/bleeding-scan.rules
#include $RULE_PATH/bleeding-storm-BLOCK.rules
include $RULE_PATH/bleeding-storm.rules
include $RULE_PATH/bleeding-virus.rules
include $RULE_PATH/bleeding-voip.rules
include $RULE_PATH/bleeding-web.rules
include $RULE_PATH/bleeding-web_sql_injection.rules
include $RULE_PATH/bleeding.rules
The Community Rules are available from http://www.snort.org. A registered
user account on http://www.snort.org is not needed to download the rules.
dentonj@darkstar:downloads$ wget http://www.snort.org/pub-bin/downloads.cgi/
Download/comm_rules/Community-Rules-CURRENT.tar.gz
dentonj@darkstar:downloads$ wget http://www.snort.org/pub-bin/downloads.cgi/
Download/comm_rules/Community-Rules-CURRENT.tar.gz.md5
dentonj@darkstar:downloads$ md5sum Community-Rules-CURRENT.tar.gz
f236b8a4ac12e99d3e7bd81bf3b5a482
dentonj@darkstar:downloads$ cat Community-Rules-CURRENT.tar.gz.md5
f236b8a4ac12e99d3e7bd81bf3b5a482
dentonj@darkstar:downloads$ su -
root@darkstar:~# cd /etc/snort
root@darkstar:snort# gzip -cd /home/dentonj/downloads/Community-Rules-CURREN
T.tar.gz | tar xf -
Configure Snort to use the Community Rules:
root@darkstar:snort# vi snort.conf
include $RULE_PATH/community-bot.rules
#include $RULE_PATH/community-deleted.rules
include $RULE_PATH/community-dos.rules
include $RULE_PATH/community-exploit.rules
include $RULE_PATH/community-ftp.rules
include $RULE_PATH/community-game.rules
include $RULE_PATH/community-icmp.rules
include $RULE_PATH/community-imap.rules
include $RULE_PATH/community-inappropriate.rules
include $RULE_PATH/community-mail-client.rules
include $RULE_PATH/community-misc.rules
include $RULE_PATH/community-nntp.rules
include $RULE_PATH/community-oracle.rules
include $RULE_PATH/community-policy.rules
include $RULE_PATH/community-sip.rules
include $RULE_PATH/community-smtp.rules
include $RULE_PATH/community-sql-injection.rules
include $RULE_PATH/community-virus.rules
include $RULE_PATH/community-web-attacks.rules
include $RULE_PATH/community-web-cgi.rules
include $RULE_PATH/community-web-client.rules
include $RULE_PATH/community-web-dos.rules
include $RULE_PATH/community-web-iis.rules
include $RULE_PATH/community-web-misc.rules
include $RULE_PATH/community-web-php.rules
Create the startup script for Snort.
root@darkstar:~# vi /etc/rc.d/rc.snort
#!/bin/sh
#
# Start/Stop/Restart Snort NIDS
#
# Specify network interface
INTERFACE="eth1"
CONF="/etc/snort/snort.conf"
snort_start() {
if ! /sbin/ifconfig $INTERFACE | grep "RUNNING" 1> /dev/null; then
echo "Bringing up interface $INTERFACE..."
/sbin/ifconfig $INTERFACE up -arp
/usr/bin/touch /var/run/snort.$INTERFACE
fi
echo "Starting Snort..."
/usr/local/bin/snort -u snort -g snort -i $INTERFACE -c $CONF \
-D -F /etc/snort/excludes.conf
}
snort_stop() {
echo "Stopping Snort..."
/bin/killall snort
if [ -e /var/run/snort.$INTERFACE ]; then
echo "Shutting down interface $INTERFACE..."
/sbin/ifconfig $INTERFACE down
/usr/bin/rm -f /var/run/snort.$INTERFACE
fi
}
snort_restart() {
snort_stop
/usr/bin/sleep 2
snort_start
}
case "$1" in
'start')
snort_start
;;
'stop')
snort_stop
;;
'restart')
snort_restart
;;
*)
echo "usage $0 start|stop|restart"
esac
--[ Configure Snort ]--
Unless otherwise specified, the configurations are for the file
/etc/snort/snort.conf.
Snort has a habit of using relative paths in snort.conf. In my experience, the
relative paths tend to do nothing but cause problems. The relative paths
assume that Snort is being started from /etc/snort. But if Snort is restarted
after editing a rule and the current working directory is /etc/snort/rules or
$HOME, then the startup may encounter problems. Yes, running the command
"cd /etc/snort" as part of the startup script could fix some of the problems.
But this assumes that Snort is always going to be started using rc.snort.
Starting Snort from the commandline with a current working directory anywhere
in the filesystem other than /etc/snort may cause problems. An example
problem is Snort reading the threshold.conf file in /etc/snort/rules instead of
/etc/snort. Use absolute paths to keep from wasting time tracking down weird
startup problems.
root@darkstar:~# vi /etc/snort/snort.conf
var RULE_PATH /etc/snort/rules
include /etc/snort/classification.config
include /etc/snort/reference.conf
include /etc/snort/threshold.conf
Snort sets HOME_NET to "any" by default. HOME_NET is used to specify the IPs
that are used by the network that you are trying to protect. HOME_NET can
either be left as "any", or it can be set. If the Snort sensor is located
near a firewall or border router, set HOME_NET to list the IP subnets that are
used on the LAN. If the Snort sensor is located in a DMZ or a single subnet on
the LAN, then set HOME_NET to the traffic the sensor can see. Setting
HOME_NET to something other than "any" can potentially reduce the number of
false positive alerts generated by Snort. To determine the network subnets the
Snort sensor can see, look at the ARP traffic.
root@darkstar:~# tcpdump -ni eth0 'arp'
var HOME_NET [192.168.0.0/16,172.16.0.0/12,10.0.0.0/8]
Set the DNS_SERVERS variable to list the DNS servers used by the network.
var DNS_SERVERS [192.168.2.3,172.18.2.4,10.1.1.5]
Set the SMTP_SERVERS variable to list the servers or bridge heads that will
be generating SMTP traffic. Setting this can cause problems with false
positives on networks that have Digital Senders if they are not listed in the
variable. Setting this variable can help detect mass-mailing worms that have
infected clients.
var SMTP_SERVERS [192.168.5.21,192.168.5.22]
If there are dedicated SQL servers on the network, set the SQL_SERVERS
variable. Setting this to list specific IPs can prevent alerts from being
generated by unauthorized SQL servers or SQL servers not listed in the
variable, such as the Snort sensor. I prefer to leave this variable set to
$HOME_NET.
var SQL_SERVERS $HOME_NET
I generally the variables TELNET_SERVERS and SNMP_SERVERS set to $HOME_NET.
Add a variable for multicast traffic and modify an existing rule to reduce
the number of false positives.
var MULTICAST_NET 224.0.0.0/4
Enable alerting on oversized lengths. Read the Snort Manual for more
information.
config enable_decode_oversized_alerts
Configure the detection engine. By default, the detection engine that is used
is "ac". With the configuration and rulesets that I use, the "ac" detection
engine can cause the Snort process to consume over 2 GB of memory. If the
system contains anything less than 4 GB of memory, use the "ac-bnfa" detection
engine.
config detection: search-method ac-bnfa
Configure the order that rules are processed. Set pass rules to be processed
first.
config order: pass alert log activation
Configure performance profiling to locate poorly performing rules. Poorly
written rules can increase the time it takes to process each packet. This
configuration will list the top 10 rules that take the most time when
evaluating a packet. The list wll be generated in /var/log/messages when
Snort is shutdown. Read the file README.PertProfiling for more information.
config profile_rules: print 10, sort total_ticks
Increase the tagged packet limit from 256 to 512.
config tagged_packet_limit: 512
Configure the target-based frag3 preprocessor. The frag3 preprocessor defines
how fragmented packets are reassembled. Different operating systems do not
reassemble fragmented packets the same way. If most of the computers on the
network are Windows systems, use the policy "windows". If you have the systems
on your network separated on different subnets, such as Linux servers on one
subnet and Windows clients on another subnet, use the "bind_to" option to set
multiple policies. I'd suggest reading the README.frag3 file, but it is not
up to date. Read the following paper for more information,
"http://www.snort.org/reg/docs/target_based_frag.pdf".
preprocessor frag3_global: max_frags 65536, prealloc_frags 65536
preprocessor frag3_engine: policy windows detect_anomalies
Configure the target-based Stream5 preprocessor. As with the frag3 preprocessor
, configure the policy to match the computers on the network. Read the file
READEME.stream5 for more information.
preprocessor stream5_global: max_tcp 8192, track_tcp yes, track_udp yes
preprocessor stream5_tcp: policy windows, detect_anomalies
preprocessor stream5_udp:
Configure capturing of performance statistics. Read the Snort Manual for more
information.
preprocessor perfmonitor: time 300 file /var/log/snort/snort.stats \
pktcnt 10000
Configure the arpspoof preprocessor to watch the default gateway. To get the
MAC address, either ping the gateway or do a DNS query. Then run the "arp"
command.
root@darkstar:~# route -n | grep UG
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
root@darkstar:~# host google.com
root@darkstar:~# arp
Address HWtype HWaddress Flags Mask Iface
192.168.1.1 ether 00:00:DE:AD:BE:EF C eth0
preprocessor arpspoof
preprocessor arpspoof_detect_host: 192.168.1.1 00:00:DE:AD:BE:EF
Configure the SSH preprocessor. The protocol mismatch and payload size
detection tend to cause a large number of false positives. Read the file
README.ssh for more information.
preprocessor ssh: server_ports { 22 } \
max_client_bytes 19600 \
max_encrypted_packets 20 \
disable_protomismatch \
disable_paysize
Configure the DCERPC preprocessor. Read the file README.dcerpc for more
information.
preprocessor dcerpc: \
ports smb { 139 445 } ports dcerpc { 135 } \
max_frag_size 3000 \
memcap 100000 \
alert_memcap
Configure the DNS preprocessor. Read the file README.dns for more information.
preprocessor dns: \
ports { 53 } \
enablerdata_overflow \
enable_obsolete_types \
enable_experimental_types
Configure the Snort output for Barnyard.
output log_unified: filename snort.log, limit 512
Add a file for IP exclusions. The rc.snort file needs to have the "-F" option
added to use the exclusions. IP exclusions can be used to ignore IP addresses
that generate a large number of false positives. An example of a system that
create a large number of false positive are the systems used to scan the
network for vulnerabilities and to verify patch compliance. Backup servers also
tend to generate a large number of alerts.
root@darkstar:~# touch /etc/snort/excludes.conf
root@darkstar:~# vi /etc/snort/excludes.conf
not src host 192.168.15.234 and
not src host 192.168.17.27
Add the classification "local" for use on custom rules. The addition makes it
easier for BASE to list the custom rules.
root@darkstar:~# vi /etc/snort/classification.config
config classification: local,Local custom rules,1
Custom rules can be added to the local.rules file. An example rule is a
Blackhole IP Address. This is a rule that looks for network traffic going to
an IP address that is not being used. Network traffic will not originate from
it, and as such, legitimate network traffic should not go to the IP address.
Anyone scanning the network for live hosts or running services will trigger the
rule and generate an alert. Read the Snort man page for more information.
root@darkstar:~# vi /etc/snort/rules/local.rules
alert ip any any -> 192.168.3.127 any (msg:"Blackhole IP Address"; class
type:local; sid:1000001; rev:1;)
Network monitoring utilities can cause the Blackhole IP Address rule to
generate alerts. These alerts are false positives, meaning the traffic the
rule is detecting is valid network traffic coming from a known host. To
suppress alerts that are known to be false positives, add a suppress rule.
Add a comment to the suppress rule to serve as a reminder six months from now.
root@darkstar:~# vi /etc/snort/threshold.conf
# Blackhole IP Address, Network Monitor
suppress gen_id 1, sig_id 1000001, track by_src, ip 192.168.5.34
Snort can have problems with dropping packets. A Snort sensor configured
to use all of the preprocessors and a large ruleset on a congested network will
more than likely drop packets. If the Snort sensor has problems with dropping
packets, disable some of the preprocessors and reduce the size of the ruleset.
Read the documentation on the Snort website and the books mentioned in the
Resources section for more information on optimizing Snort.
Snort generates and logs statistics while shutting down.
root@darkstar:~# grep Dropped /var/log/messages*
root@darkstar:~# zgrep Dropped /var/log/messages*.gz
If the preprocessor perfmonitor is configured, Snort will periodically insert
statistics into the file snort.stats. Each line of this file contains 52
fields. A listing of information contained in each field is listed in the
Snort Manual. The "Drop Rate" is listed in the second field. Yes, the Snort
Manual does not explain what all of the fields are for. Ask the developers or
look at the source code.
http://www.snort.org/docs/snort_htmanuals/htmanual_2615/node59.html
root@darkstar:~# tail -n 1 /var/log/snort/snort.stats | awk -F, '{print NF}'
root@darkstar:~# less /var/log/snort/snort.stats
The snort.conf configuration file:
root@darkstar:~# grep -v "^#" /etc/snort/snort.conf | grep -v "^$"
var HOME_NET [192.168.0.0/16,172.16.0.0/12,10.0.0.0/8]
var EXTERNAL_NET any
var DNS_SERVERS [192.168.2.3,172.18.2.4,10.1.1.5]
var SMTP_SERVERS [192.168.5.21,192.168.5.22]
var HTTP_SERVERS $HOME_NET
var SQL_SERVERS $HOME_NET
var TELNET_SERVERS $HOME_NET
var SNMP_SERVERS $HOME_NET
var HTTP_PORTS 80
var SHELLCODE_PORTS !80
var ORACLE_PORTS 1521
var MULTICAST_NET 224.0.0.0/4
var AIM_SERVERS [64.12.24.0/23,64.12.28.0/23,64.12.161.0/24,64.12.163.0/
24,64.12.200.0/24,205.188.3.0/24,205.188.5.0/24,205.188.7.0/24,205.188.9.0/24,20
5.188.153.0/24,205.188.179.0/24,205.188.248.0/24]
var RULE_PATH /etc/snort/rules
config enable_decode_oversized_alerts
config detection: search-method ac-bnfa
config order: pass alert log activation
config profile_rules: print 10, sort total_ticks
dynamicpreprocessor directory /usr/local/lib/snort_dynamicpreprocessor/
dynamicengine /usr/local/lib/snort_dynamicengine/libsf_engine.so
dynamicdetection directory /usr/local/lib/snort_dynamicrule/
preprocessor frag3_global: max_frags 65536, prealloc_frags 65536
preprocessor frag3_engine: policy windows detect_anomalies
preprocessor stream5_global: max_tcp 8192, track_tcp yes, \
track_udp yes
preprocessor stream5_tcp: policy windows, detect_anomalies
preprocessor stream5_udp:
preprocessor perfmonitor: time 300 file /var/log/snort/snort.stats \
pktcnt 10000
preprocessor http_inspect: global \
iis_unicode_map unicode.map 1252
preprocessor http_inspect_server: server default \
profile all ports { 80 8080 8180 } oversize_dir_length 500
preprocessor rpc_decode: 111 32771
preprocessor bo
preprocessor ftp_telnet: global \
encrypted_traffic yes \
inspection_type stateful
preprocessor ftp_telnet_protocol: telnet \
normalize \
ayt_attack_thresh 200
preprocessor ftp_telnet_protocol: ftp server default \
def_max_param_len 100 \
alt_max_param_len 200 { CWD } \
cmd_validity MODE < char ASBCZ > \
cmd_validity MDTM < [ date nnnnnnnnnnnnnn[.n[n[n]]] ] string > \
chk_str_fmt { USER PASS RNFR RNTO SITE MKD } \
telnet_cmds yes \
data_chan
preprocessor ftp_telnet_protocol: ftp client default \
max_resp_len 256 \
bounce yes \
telnet_cmds yes
preprocessor smtp: \
ports { 25 } \
inspection_type stateful \
normalize cmds \
normalize_cmds { EXPN VRFY RCPT } \
alt_max_command_line_len 260 { MAIL } \
alt_max_command_line_len 300 { RCPT } \
alt_max_command_line_len 500 { HELP HELO ETRN } \
alt_max_command_line_len 255 { EXPN VRFY }
preprocessor arpspoof
preprocessor arpspoof_detect_host: 192.168.1.27 00:00:DE:AD:BE:EF
preprocessor ssh: server_ports { 22 } \
max_client_bytes 19600 \
max_encrypted_packets 20 \
disable_protomismatch \
disable_paysize
preprocessor dcerpc: \
ports smb { 139 445 } ports dcerpc { 135 } \
max_frag_size 3000 \
memcap 100000 \
alert_memcap
preprocessor dns: \
ports { 53 } \
enable_rdata_overflow \
enable_obsolete_types \
enable_experimental_types
output log_unified: filename snort.log, limit 512
include /etc/snort/classification.config
include /etc/snort/reference.config
include $RULE_PATH/local.rules
include $RULE_PATH/bad-traffic.rules
include $RULE_PATH/exploit.rules
include $RULE_PATH/scan.rules
include $RULE_PATH/finger.rules
include $RULE_PATH/ftp.rules
include $RULE_PATH/telnet.rules
include $RULE_PATH/rpc.rules
include $RULE_PATH/rservices.rules
include $RULE_PATH/dos.rules
include $RULE_PATH/ddos.rules
include $RULE_PATH/dns.rules
include $RULE_PATH/tftp.rules
include $RULE_PATH/web-cgi.rules
include $RULE_PATH/web-coldfusion.rules
include $RULE_PATH/web-iis.rules
include $RULE_PATH/web-frontpage.rules
include $RULE_PATH/web-misc.rules
include $RULE_PATH/web-client.rules
include $RULE_PATH/web-php.rules
include $RULE_PATH/sql.rules
include $RULE_PATH/x11.rules
include $RULE_PATH/icmp.rules
include $RULE_PATH/netbios.rules
include $RULE_PATH/misc.rules
include $RULE_PATH/attack-responses.rules
include $RULE_PATH/oracle.rules
include $RULE_PATH/mysql.rules
include $RULE_PATH/snmp.rules
include $RULE_PATH/smtp.rules
include $RULE_PATH/imap.rules
include $RULE_PATH/pop2.rules
include $RULE_PATH/pop3.rules
include $RULE_PATH/nntp.rules
include $RULE_PATH/other-ids.rules
include $RULE_PATH/web-attacks.rules
include $RULE_PATH/backdoor.rules
include $RULE_PATH/shellcode.rules
include $RULE_PATH/policy.rules
include $RULE_PATH/porn.rules
include $RULE_PATH/info.rules
include $RULE_PATH/icmp-info.rules
include $RULE_PATH/virus.rules
include $RULE_PATH/chat.rules
include $RULE_PATH/multimedia.rules
include $RULE_PATH/p2p.rules
include $RULE_PATH/spyware-put.rules
include $RULE_PATH/specific-threats.rules
include $RULE_PATH/experimental.rules
include $RULE_PATH/so.rules
include $RULE_PATH/bleeding.conf
include $RULE_PATH/bleeding-attack_response.rules
include $RULE_PATH/bleeding-botcc.rules
include $RULE_PATH/bleeding-compromised.rules
include $RULE_PATH/bleeding-dos.rules
include $RULE_PATH/bleeding-drop.rules
include $RULE_PATH/bleeding-dshield.rules
include $RULE_PATH/bleeding-exploit.rules
include $RULE_PATH/bleeding-game.rules
include $RULE_PATH/bleeding-inappropriate.rules
include $RULE_PATH/bleeding-malware.rules
include $RULE_PATH/bleeding-p2p.rules
include $RULE_PATH/bleeding-policy.rules
include $RULE_PATH/bleeding-scan.rules
include $RULE_PATH/bleeding-storm.rules
include $RULE_PATH/bleeding-virus.rules
include $RULE_PATH/bleeding-voip.rules
include $RULE_PATH/bleeding-web.rules
include $RULE_PATH/bleeding-web_sql_injection.rules
include $RULE_PATH/bleeding.rules
include $RULE_PATH/community-bot.rules
include $RULE_PATH/community-deleted.rules
include $RULE_PATH/community-dos.rules
include $RULE_PATH/community-exploit.rules
include $RULE_PATH/community-ftp.rules
include $RULE_PATH/community-game.rules
include $RULE_PATH/community-icmp.rules
include $RULE_PATH/community-imap.rules
include $RULE_PATH/community-inappropriate.rules
include $RULE_PATH/community-mail-client.rules
include $RULE_PATH/community-misc.rules
include $RULE_PATH/community-nntp.rules
include $RULE_PATH/community-oracle.rules
include $RULE_PATH/community-policy.rules
include $RULE_PATH/community-sip.rules
include $RULE_PATH/community-smtp.rules
include $RULE_PATH/community-sql-injection.rules
include $RULE_PATH/community-virus.rules
include $RULE_PATH/community-web-attacks.rules
include $RULE_PATH/community-web-cgi.rules
include $RULE_PATH/community-web-client.rules
include $RULE_PATH/community-web-dos.rules
include $RULE_PATH/community-web-iis.rules
include $RULE_PATH/community-web-misc.rules
include $RULE_PATH/community-web-php.rules
include /etc/snort/threshold.conf
--[ Configure MySQL ]--
MySQL should be installed during the installation of Slackware. To check to
see if MySQL is installed:
dentonj@darkstar:~$ /usr/libexec/mysqld --version
usr/libexec/mysqld Ver 5.0.37 for slackware-linux-gnu on i486 (Source distr
ibution)
By default, MySQL will not start in Slackware. The mysql database must first
be created.
dentonj@darkstar:~$ su -
root@darkstar:~# su - mysql
mysql@darkstar:~$ mysql_install_db
mysql@darkstar:~$ exit
Slackware prevents MySQL from accepting network connections by default.
Comment out the following line:
root@darkstar:~# vi /etc/rc.d/rc.mysqld
#SKIP="--skip-networking"
Change the permissions on the RC file and start MySQL:
root@darkstar:~# chmod 700 /etc/rc.d/rc.mysqld
root@darkstar:~# /etc/rc.d/rc.mysqld start
Secure MySQL before continuing. Run the following command and answer the
questions as follows:
root@darkstar:~# mysql_secure_installation
Set root password? Y
Remove anonymous users? Y
Disallow root login remotely? Y
Remove test database and access to it? Y
Reload privilege tables now? Y
Create the tables for the snort database:
root@darkstar:~# mysql -p < /home/dentonj/src/snort-2.7.0.1/schemas/create_m
ysql snort
Check the tables:
root@darkstar:~# mysql -p
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| snort |
+--------------------+
3 rows in set (0.01 sec)
mysql> use snort;
mysql> show tables;
+------------------+
| Tables_in_snort |
+------------------+
| data |
| detail |
| encoding |
| event |
| icmphdr |
| iphdr |
| opt |
| reference |
| reference_system |
| schema |
| sensor |
| sig_class |
| sig_reference |
| signature |
| tcphdr |
| udphdr |
+------------------+
16 rows in set (0.01 sec)
mysql> exit
The mysql client logs all commands to a history file. Any commands that set
passwords will be saved in the history file. If the idea of passwords to MySQL
being present in the history file bothers you, overwrite the file.
root@darkstar:~# less .mysql_history
root@darkstar:~# cat /dev/null > .mysql_history
There are four example my.cnf files in the /etc directory. The differences
between them is how much memory is configured for use by MySQL. Copy the
appropriate configuration file to /etc/my.cnf.
root@darkstar:~# cp /etc/my-huge.cnf /etc/my.cnf
From "man mysqld", "To avoid a possible security hole where a user adds a
--user=root option to a my.cnf file (thus causing the server to run as root),
mysqld uses only the first --user option specified and produces a warning if
there are multiple --user options. Options in /etc/my.cnf and
$MYSQL_HOME/my.cnf are processed before command-line options, so it is
recommended that you put a --user option in /etc/my.cnf and specify a value
other than root." Add the following the the "[mysqld]" section of the
configuration file:
root@darkstar:~# vi /etc/my.cnf
user = mysql
The Snort sensor is not going to have any entries in a DNS server. Hostnames
do not need to be resolved. All grant statements must be an IP address or
localhost. A slight performance increase may be gained by not resolving
hostnames. Add the following in the "[mysqld]" section of the configuration
file:
root@darkstar:~# vi /etc/my.cnf
skip-name-resolve
There is only going to be one instance of mysqld running on the Snort sensor.
The snort database is not going to be shared with any other process. External
locking can be disabled to gain a slight performance boost. Add the following
in the "[mysqld]" section of the configuration file:
root@darkstar:~# vi /etc/my.cnf
skip-external-locking
Do not allow authentication to mysqld for accounts that use old (pre-4.1)
passwords. Prevent the mysql client from connecting to a server that requires
a password in the old format. Add the following in the "[mysqld]" and
"[mysql]" sections of the configuration file:
root@darkstar:~# vi /etc/my.cnf
secure-auth
The MySQL storage engine that is used by default is MyISAM. The InnoDB storage
engine can be disabled. Add the following:
root@darkstar:~# vi /etc/rc.d/rc.mysqld
SKIP="--skip-innodb"
Restart MySQL so the configuration changes take effect:
root@darkstar:~# /etc/rc.d/rc.mysqld restart
--[ BASE Installation ]--
Before we can install BASE, some prerequisits for PHP must first be installed.
The command "pear" is used to download and install packages from the PHP
Extension and Application Repository.
dentonj@darkstar:~$ su -
root@darkstar:~# pear install --alldeps Image_Graph-alpha
Image_Canvas-alpha Image_Color Numbers_Roman
root@darkstar:~# pear list
Installed packages, channel pear.php.net:
=========================================
Package Version State
Archive_Tar 1.3.2 stable
Console_Getopt 1.2.2 stable
Image_Canvas 0.3.1 alpha
Image_Color 1.0.2 stable
Image_Graph 0.7.2 alpha
Numbers_Roman 0.2.0 stable
Numbers_Words 0.15.0 beta
PEAR 1.5.4 stable
Structures_Graph 1.0.2 stable
ADODB is a database abstraction library for PHP. It is required by BASE.
Download ADODB and BASE:
dentonj@darkstar:~/downloads$ wget http://easynews.dl.sourceforge.net/source
forge/adodb/adodb480.tgz
dentonj@darkstar:~/downloads$ wget http://easynews.dl.sourceforge.net/source
forge/secureideas/base-1.3.8.tar.gz
Check http://base.secureideas.net to determine which verson of BASE is the
latest. Note: base-1.3.8 was not listed on the home page when this was
written. Check the "Downloads" link.
Extract ADODB:
dentonj@darkstar:downloads$ su -
root@darkstar:~# cd /var/www
root@darkstar:www# tar xvf /home/dentonj/downloads/adodb480.tgz
ADODB is nice enough to be distributed with world writable files. Fix this
problem:
root@darkstar:www# chmod -R o-w adodb
Extract BASE:
root@darkstar:www# cd htdocs
root@darkstar:htdocs# tar zxf /home/dentonj/downloads/base-1.3.8.tar.gz
root@darkstar:htdocs# mv base-1.3.8 frontend
It's common to rename the base-1.3.8 directory to base or create a symlink. I
rename the directory to something that is not so obvious and is not checked by
Nikto to provide some obfuscation.
Configure BASE:
root@darkstar:htdocs# cd frontend
root@darkstar:frontend# cp base_conf.php.dist base_conf.php
root@darkstar:frontend# vi base_conf.php
$BASE_urlpath = '/frontend';
$DBlib_path = '/var/www/adodb';
$DBtype = 'mysql';
$alert_dbname = 'snort';
$alert_host = 'localhost';
$alert_port = '';
$alert_user = 'snort';
$alert_password = 'mysqlsnortpassword';
$show_rows = 90;
$show_expanded_query = 1;
$colored_alerts = 1;
Change the following line from:
$priority_colors = array('FF0000','FFFF00','FF9900','999999','FFFFFF','0
06600');
To:
$priority_colors = array('000000','FF0000','FF9900','FFFF00','999999');
Snort uses the priorities 1 through 4. The array starts counting from zero. I
also changed the order of the colors and remove the excess.
Some of the Snort rules are documented to explain what the rule is looking for.
BASE is setup to create links to this documentation. Copy the rule
documentation directory into the BASE directory.
root@darkstar:frontend# cd /home/dentonj/src/snort-2.7.0.1/doc
root@darkstar:doc# cp -r signatures /var/www/htdocs/frontend
--[ Configure the web server ]--
BASE should only be accessed using SSL. The Apache web server needs to be
configured to use SSL. Apache also needs to be locked down a little bit.
Enable loading of the SSL modules and the configuration file for SSL.
Uncomment the following lines:
root@darkstar:~# vi /etc/httpd/httpd.conf
LoadModule ssl_module lib/httpd/modules/mod_ssl.so
Include /etc/httpd/extra/httpd-ssl.conf
Set the server's name to localhost and add a line to slow down fingerprinting
of the server. Add the following:
root@darkstar:~# vi /etc/httpd/httpd.conf
ServerName localhost
ServerSignature Off
Configure the Pseudo Random Number Generator. Uncomment the following lines:
root@darkstar:~# vi /etc/httpd/extra/httpd-ssl.conf
SSLRandomSeed startup file:/dev/urandom 512
SSLRandomSeed connect file:/dev/urandom 512
The web server needs a server certificate and a server private key to use SSL.
The keys are going to be created without a passphrase. If a passphrase is
used, that passphrase must be entered everytime the web server starts.
root@darkstar:~# openssl genrsa -out server.key 2048
root@darkstar:~# openssl req -new -key server.key -out server.csr
root@darkstar:~# openssl x509 -reg -days 1095 -in server.csr -signkey server
.key -out server.crt
Copy the server certificate and the server private key into /etc/httpd:
root@darkstar:~# cp server.key /etc/httpd
root@darkstar:~# cp server.crt /etc/httpd
root@darkstar:~# chmod 400 /etc/httpd/server.*
There are a number of files and directories in /var/www/htdocs that can be
used to identify the web server. We are not going to use a local search
engine, so htdig can be removed from the system. The Apache manual can be
moved to another location so that it is still available if needed. The rest
of the files can be deleted.
root@darkstar:~# removepkg htdig
root@darkstar:~# mv /var/www/htdocs/manual /var/www
root@darkstar:~# rm /var/www/htdocs/apache_pb*
Create an empty index.html file.
root@darkstar:~# cat /dev/null > /var/www/htdocs/index.html
Restrict access to the BASE directory to authorized users. Create the password
file and configure the users that will be allowed to access BASE.
root@darkstar:~# mkdir /var/www/passwords
root@darkstar:~# htpasswd -c /var/www/passwords/passwords dentonj
root@darkstar:~# htpasswd /var/www/passwords/passwords baseuser
root@darkstar:~# chmod -R o-rwx /var/www/passwords
Configure the BASE directory to only allow access to authorized users.
Slackware follows the Filesystem Hierarchy Standard. Because of this standard,
the directory /srv is the location for data for services provided by the
system. While the directory /srv contains a symlink to /var/www, the directive
DocumentRoot is set to /srv/httpd/htdocs. Basic authentication is OK when used
with SSL. I have not been able to get BASE to work properly with Digest
authentication. Add the following:
root@darkstar:~# vi /etc/httpd/httpd.conf
<Directory "/srv/httpd/htdocs/frontend">
AuthType Basic
AuthName "Authentication"
AuthUserFile /srv/httpd/passwords/passwords
Require user dentonj baseuser
</Directory>
Most of the Apache modules are not needed. Comment out the following:
root@darkstar:~# vi /etc/httpd/httpd.conf
#LoadModule authn_dbm_module lib/httpd/modules/mod_authn_dbm.so
#LoadModule authn_anon_module lib/httpd/modules/mod_authn_anon.so
#LoadModule authn_dbd_module lib/httpd/modules/mod_authn_dbd.so
#LoadModule authn_default_module lib/httpd/modules/mod_authn_default.so
#LoadModule authn_alias_module lib/httpd/modules/mod_authn_alias.so
#LoadModule authz_groupfile_module lib/httpd/modules/mod_authz_groupfile
.so
#LoadModule authz_dbm_module lib/httpd/modules/mod_authz_dbm.so
#LoadModule authz_owner_module lib/httpd/modules/mod_authz_owner.so
#LoadModule authnz_ldap_module lib/httpd/modules/mod_authnz_ldap.so
#LoadModule authz_default_module lib/httpd/modules/mod_authz_default.so
#LoadModule auth_digest_module lib/httpd/modules/mod_auth_digest.so
#LoadModule file_cache_module lib/httpd/modules/mod_file_cache.so
#LoadModule cache_module lib/httpd/modules/mod_cache.so
#LoadModule disk_cache_module lib/httpd/modules/mod_disk_cache.so
#LoadModule mem_cache_module lib/httpd/modules/mod_mem_cache.so
#LoadModule dbd_module lib/httpd/modules/mod_dbd.so
#LoadModule dumpio_module lib/httpd/modules/mod_dumpio.so
#LoadModule ext_filter_module lib/httpd/modules/mod_ext_filter.so
#LoadModule include_module lib/httpd/modules/mod_include.so
#LoadModule filter_module lib/httpd/modules/mod_filter.so
#LoadModule deflate_module lib/httpd/modules/mod_deflate.so
#LoadModule ldap_module lib/httpd/modules/mod_ldap.so
#LoadModule log_forensic_module lib/httpd/modules/mod_log_forensic.so
#LoadModule logio_module lib/httpd/modules/mod_logio.so
#LoadModule env_module lib/httpd/modules/mod_env.so
#LoadModule cern_meta_module lib/httpd/modules/mod_cern_meta.so
#LoadModule expires_module lib/httpd/modules/mod_expires.so
#LoadModule headers_module lib/httpd/modules/mod_headers.so
#LoadModule ident_module lib/httpd/modules/mod_ident.so
#LoadModule usertrack_module lib/httpd/modules/mod_usertrack.so
#LoadModule version_module lib/httpd/modules/mod_version.so
#LoadModule proxy_module lib/httpd/modules/mod_proxy.so
#LoadModule proxy_connect_module lib/httpd/modules/mod_proxy_connect.so
#LoadModule proxy_ftp_module lib/httpd/modules/mod_proxy_ftp.so
#LoadModule proxy_http_module lib/httpd/modules/mod_proxy_http.so
#LoadModule proxy_ajp_module lib/httpd/modules/mod_proxy_ajp.so
#LoadModule proxy_balancer_module lib/httpd/modules/mod_proxy_balancer.s
o
#LoadModule dav_module lib/httpd/modules/mod_dav.so
#LoadModule status_module lib/httpd/modules/mod_status.so
#LoadModule autoindex_module lib/httpd/modules/mod_autoindex.so
#LoadModule asis_module lib/httpd/modules/mod_asis.so
#LoadModule info_module lib/httpd/modules/mod_info.so
#LoadModule cgi_module lib/httpd/modules/mod_cgi.so
#LoadModule dav_fs_module lib/httpd/modules/mod_dav_fs.so
#LoadModule vhost_alias_module lib/httpd/modules/mod_vhost_alias.so
#LoadModule negotiation_module lib/httpd/modules/mod_negotiation.so
#LoadModule imagemap_module lib/httpd/modules/mod_imagemap.so
#LoadModule actions_module lib/httpd/modules/mod_actions.so
#LoadModule userdir_module lib/httpd/modules/mod_userdir.so
#LoadModule alias_module lib/httpd/modules/mod_alias.so
#LoadModule rewrite_module lib/httpd/modules/mod_rewrite.so
Change the permissions of the startup script and start the web server:
root@darkstar:~# chmod 700 /etc/rc.d/rc.httpd
root@darkstar:~# /etc/rc.d/rc.httpd start
To test SSL on the web server, run the following command. When the cursor is
sitting on a blank line, type "GET /frontend".
dentonj@darkstar:~$ openssl s_client -connect localhost:443
GET /frontend
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>401 Authorization Required</title>
</head><body>
<h1>Authorization Required</h1>
<p>This server could not verify that you
are authorized to access the document
requested. Either you supplied the wrong
credentials (e.g., bad password), or your
browser doesn't understand how to supply
the credentials required.</p>
</body></html>
closed
When running the above command, ensure the following is seen:
New, TLSv1/SSLv3, Cipher is DHE-RSA-AES256-SHA
Server public key is 2048 bit
--[ Configure PHP ]--
PHP must be configured before BASE will function.
root@darkstar:~# vi /etc/httpd/httpd.conf
Include /etc/httpd/mod_php.conf
Change the DirectoryIndex directive to allowing loading of PHP index files.
root@darkstar:~# vi /etc/httpd/httpd.conf
Modify the following line from:
DirectoryIndex index.html
To:
DirectoryIndex index.html index.php
Secure PHP a bit by changing the following:
root@darkstar:~# vi /etc/httpd/php.ini
safe_mode = On
all_url_fopen = Off
allow_url_fopen = Off
file_uploads = Off
open_basedir = /var/www
disable_functions = system,exec,shell_exec,eval,include,require,include_
once,require_once
expose_php = Off
error_log = /var/log/httpd/php_error_log
Create the php_error_log and restart the web server so the configuration
changes take effect:
root@darkstar:~# touch /var/log/httpd/php_error_log
root@darkstar:~# /etc/rc.d/rc.httpd restart
--[ Configure the firewall ]--
The startup script /etc/rc.d/rc.inet2 will start the file /etc/rc.d/rc.firewall
if it exists. The file rc.firewall does not exist by default. Create the file
and add the following:
root@darkstar:~# vi /etc/rc.d/rc.firewall
# rc.firewall
#
firewall_start() {
echo "Starting Iptables..."
/usr/sbin/iptables -P INPUT DROP
/usr/sbin/iptables -P FORWARD DROP
/usr/sbin/iptables -A INPUT -i lo -j ACCEPT
/usr/sbin/iptables -A INPUT -p icmp --icmp-type any -j DROP
/usr/sbin/iptables -A INPUT -m state --state ESTABLISHED,RELATED -j AC
CEPT
/usr/sbin/iptables -A INPUT -m state --state NEW -m tcp -p tcp -s 192.
168.1.0/24 --dport 22 -j ACCEPT
/usr/sbin/iptables -A INPUT -m state --state NEW -m tcp -p tcp -s 192.
168.1.0/24 --dport 443 -j ACCEPT
/usr/sbin/iptables -A INPUT -m state --state NEW -m tcp -p tcp -s 192.
168.1.0/24 --dport 3001 -j ACCEPT
/usr/sbin/iptables -A INPUT -m state --state NEW -m tcp -p tcp -s 192.
168.1.0/24 --dport 3307 -j ACCEPT
# Drop broadcasts before logging
/usr/sbin/iptables -A INPUT -d 192.168.1.255 -j DROP
/usr/sbin/iptables -A INPUT -j LOG --log-ip-options --log-tcp-options
#/usr/sbin/iptables -A INPUT -j REJECT --reject-with icmp-host-prohibi
ted
/usr/sbin/iptables -A INPUT -j DROP
}
firewall_stop() {
echo "Stopping Iptables..."
/usr/sbin/iptables -P INPUT ACCEPT
/usr/sbin/iptables -P FORWARD ACCEPT
/usr/sbin/iptables -F
}
firewall_restart() {
firewall_stop
/usr/bin/sleep 2
firewall_start
}
case "$1" in
'start')
firewall_start
;;
'stop')
firewall_stop
;;
'restart')
firewall_restart
;;
*)
echo "usage $0 start|stop|restart"
esac
If you regularly VPN into your network, remember to add that subnet to allow
access.
Change the permissions and start the firewall script:
root@darkstar:~# chmod 700 /etc/rc.d/rc.firewall
root@darkstar:~# /etc/rc.d/rc.firewall start
root@darkstar:~# iptables -L -nv
--[ Create the BASE tables ]--
With a web browser:
- Go to https://<sensor ip>/frontend
- Click on the "Setup page" link
- Click on the "Create BASE AG" button
- Click on the "Main Page" link
--[ Create the archive database]--
There probably is a better way to do this, but it works. Unfortunately, the
setup page for BASE is not able to create the BASE specific tables in the Snort
archive database. Copy the snort database and name the copy snort_archive.
root@darkstar:~# /etc/rc.d/rc.mysqld stop
root@darkstar:~# cd /var/lib/mysql
root@darkstar:mysql# cp -pr snort snort_archive
root@darkstar:mysql# /etc/rc.d/rc.mysqld start
Configure the permissions in MySQL:
root@darkstar:~# mysql -p
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| snort |
| snort_archive |
+--------------------+
4 rows in set (0.00 sec)
mysql> grant create,insert,select,delete,update on snort_archive.* to snort@
localhost;
mysql> grant create,insert,select,delete,update on snort_archive.* to snort;
mysql> flush privileges;
mysql> use snort;
mysql> show tables;
+------------------+
| Tables_in_snort |
+------------------+
| acid_ag |
| acid_ag_alert |
| acid_event |
| acid_ip_cache |
| base_roles |
| base_users |
| data |
| detail |
| encoding |
| event |
| icmphdr |
| iphdr |
| opt |
| reference |
| reference_system |
| schema |
| sensor |
| sig_class |
| sig_reference |
| signature |
| tcphdr |
| udphdr |
+------------------+
22 rows in set (0.00 sec)
mysql> exit
Configure BASE to use the archive database:
root@darkstar:~# vi /var/www/htdocs/frontend/base_conf.php
$archive_exists = 1;
$archive_dbname = 'snort_archive';
$archive_host = 'localhost';
$archive_port = '';
$archive_user = 'snort';
$archive_password = 'mysqlsnortpassword';
--[ Barnyard Installation ]--
Barnyard is used to separate Snort from the database. Snort uses a single
process for all packet processing and logging. Logging directory from Snort
into a database is slow and can potentially cause Snort to start dropping
packets. The solution is to have Snort log to files and use Barnyard to take
the alerts in the files and stuff them into the database.
dentonj@darkstar:downloads$ wget http://www.snort.org/dl/barnyard/barnyard-0
.2.0.tar.gz
dentonj@darkstar:downloads$ wget http://www.snort.org/dl/barnyard/barnyard-0
.2.0.tar.gz.md5
dentonj@darkstar:downloads$ md5sum barnyard-0.2.0.tar.gz
be3283028cf414b52b220308ceb411e9 barnyard-0.2.0.tar.gz
dentonj@darkstar:downloads$ cat barnyard-0.2.0.tar.gz.md5
md5 : be3283028cf414b52b220308ceb411e9 barnyard-0.2.0.tar.gz
sha1 : 4adfcabb2702def5a9a6c68cbde1b90a70f7e67a barnyard-0.2.0.tar.gz
dentonj@darkstar:downloads$ cd ../src
dentonj@darkstar:src$ gzip -cd ../downloads/barnyard-0.2.0.tar.gz | tar xf -
dentonj@darkstar:src$ cd barnyard-0.2.0
denotnj@darkstar:barnyard-0.2.0$ ./configure --enable-mysql
dentonj@darkstar:barnyard-0.2.0$ make
dentonj@darkstar:barnyard-0.2.0$ su
root@darkstar:barnyard-0.2.0# make install
Barnyard does not insert an entry into the sensor table in the snort database.
Not having an entry in this table will prevent BASE from updating its tables
and prevent alerts from being displayed through the BASE interface in the web
browser. Manually add an entry into the snort.sensor table:
root@darkstar:~# mysql -p
mysql> use snort;
mysql> insert into snort.sensor (sid,hostname,interface,filter,detail,encodi
ng,last_cid) values (1,"localhost","eth1","",1,0,0);
mysql> select * from snort.sensor;
mysql> exit
The commands used to troubleshoot this problem:
root@darkstar:~# mysql -p
mysql> use snort;
mysql> select count(*) from event;
+----------+
| count(*) |
+----------+
| 4561 |
+----------+
1 row in set (0.00 sec)
mysql> select count(*) from acid_event;
+----------+
| count(*) |
+----------+
| 0 |
+----------+
1 row in set (0.00 sec)
mysql> select * from sensor;
Empty set (0.00 sec)
Barnyard uses a file to keep track of the alerts that have been inserted into
the database. Create this file:
root@darkstar:~# vi /var/log/snort/barnyard.waldo
/var/log/snort
snort.log
0
0
Configure Barnyard:
root@darkstar:~# vi /etc/snort/barnyard.conf
config daemon
config localtime
config hostname: localhost
config interface: eth0
config filter: not src host 192.168.15.234 and \
not src host 192.168.17.27
config sid-msg-map: /etc/snort/sid-msg.map
config gen-msg-map: /etc/snort/gen-msg.map
config class-file: /etc/snort/classification.config
output log_acid_db: mysql, sensor_id 1, database snort, server localhost
, user snort, detail full, password mysqlsnortpassword
Create the startup script used to start Barnyard:
root@darkstar:~# vi /etc/rc.d/rc.barnyard
#!/bin/sh
#
# Start/Stop/Restart Barnyard
#
CONF="/etc/snort/barnyard.conf"
barnyard_start() {
echo "Starting Barnyard..."
/usr/local/bin/barnyard -v -c $CONF \
-d /var/log/snort \
-f snort.log \
-w /var/log/snort/barnyard.waldo \
-a /var/log/snort/archive \
-X /var/run/barnyard.pid
}
barnyard_stop() {
echo "Stopping Barnyard..."
/bin/killall barnyard
}
barnyard_restart() {
barnyard_stop
/usr/bin/sleep 2
barnyard_start
}
case "$1" in
'start')
barnyard_start
;;
'stop')
barnyard_stop
;;
'restart')
barnyard_restart
;;
*)
echo "usage $0 start|stop|restart"
esac
Change the permissions for the startup script:
root@darkstar:~# chmod 700 /etc/rc.d/rc.barnyard
--[ Oinkmaster Installation ]--
Oinkmaster is used to manage the rules used by Snort. Oinkmaster can download
and update new rules. It can also enable, disable, and modify rules after
each update.
dentonj@darkstar:downloads$ wget http://easynews.dl.sourceforge.net/sourcefo
rge/oinkmaster/oinkmaster-2.0.tar.gz
dentonj@darkstar:downloads$ cd ../src
dentonj@darkstar:src$ gzip -cd ../downloads/oinkmaster-2.0.tar.gz | tar xf -
dentonj@darkstar:src$ cd oinkmaster-2.0
dentonj@darkstar:oinkmaster-2.0$ su
root@darkstar:oinkmaster-2.0# cp oinkmaster.pl /usr/local/sbin
root@darkstar:oinkmaster-2.0# cp oinkmaster.conf /etc
root@darkstar:oinkmaster-2.0# cp oinkmaster.1 /usr/local/man/man1
root@darkstar:oinkmaster-2.0# cd contrib
root@darkstar:contrib# cp *.pl /usr/local/sbin
Configure Oinkmaster to update the rules. If you have registered as a user on
the Snort website, then get the Oink Code to download the VRT rules. The Oink
Code can be obtained on the user preference page on the Snort website. Setup
Oinkmaster to download the VRT rules, the latest Bleeding Threats rules, and
the Community rules.
root@darkstar:~# vi /etc/oinkmaster.conf
url = http://www.snort.org/pub-bin/oinkmaster.cgo/GetYourOwnCode012345ab
cde6789fg0123456789/snortrules-snapshot-CURRENT.tar.gz
url = http://www.bleedingthreats.net/rules/bleeding.rules.tar.gz
url = http://www.snort.org/pub-bin/downloads.cgi/
Download/comm_rules/Community-Rules-CURRENT.tar.gz
path = /bin:/usr/bin:/usr/local/bin
update_files = \.rules$|\.txt$|\.map$
skipfile local.rules
skipfile snort.conf
skipfile threshold.conf
skipfile classification.config
skipfile reference.config
When updating the rules, run a check first. The only problem with this is the
Snort website only allows downloads of the VRT rules once every 15 minutes. If
this annoys you too, download the VRT rules separately and configure Oinkmaster
with , "url = file///home/dentonj/downloads/snortrules-snapshot-CURRENT.tar.gz".
root@darkstar:~# oinkmaster.pl -c -o /etc/snort/rules > oinktest
15 minutes later....
root@darkstar:~# oinkmaster.pl -o /etc/snort/rules
Each rules contains a unique Snort rule ID (SID). The file sid-msg.map
contains the mapping of alert messages to SIDs. Since Barnyard does not read
the rules files, the sid-msg.map file is used when feeding alerts into MySQL.
If the file is out of date, meaning there are SIDs in the rules files that are
not listed in the sid-msg.map file, Barnyard will not be able to insert the
alert message into MySQL. The result will be seen in BASE with an alert such
as "Snort Alert [1:1948:15]". Everytime the rules are updated or a new rule is
added, the sid-msg.map file needs to be recreated.
root@darkstar:~# create-sidmap.pl /etc/snort/rules > /etc/snort/sid-msg.map
There are over 3600 rules disabled by default in the VRT rules. There are
over 400 rules disabled by default in the Bleeding Threat rules. The rules
are disabled by default for various reasons.
- The rules could generate a large number of false positive either generally
or in certain environments.
- The rules are only useful in specific environments, so it's not worth
making Snort work harder unless your environment has the specific
thing the rule is looking for.
- The rules are performance hogs and should be enabled only if you are
really concerned about what the rule is looking for.
Spend some time going through the rules files to determine if there is anything
that needs to be enabled. To generate a list of the disabled SIDs:
root@darkstar:~# makesidex.pl /etc/snort/rules > /etc/snort/disablesid.conf
To enable a rule, uncomment the rule itself in the appropriate file. To ensure
that Oinkmaster does not disable the rule when rules are updated, add an
"enablesid" line to the Oinkmaster configuration file.
root@darkstar:~# cd /etc/snort/rules
root@darkstar:rules# grep -n "DNS zone transfer" *
dns.rules:23:# alert tcp $EXTERNAL_NET any -> $HOME_NET 53 (msg:"DNS zone tr
ansfer TCP"; flow:to_server,established; content:"|00 00 FC|"; offset:15; metada
ta:service dns; reference:arachnids,212; reference:cve,1999-0532; reference:ness
us,10595; classtype:attempted-recon; sid:255; rev:15;)
dns.rules:24:# alert udp $EXTERNAL_NET any -> $HOME_NET 53 (msg:"DNS zone tr
ansfer UDP"; content:"|00 00 FC|"; offset:14; metadata:service dns; reference:ar
achnids,212; reference:cve,1999-0532; reference:nessus,10595; classtype:attempte
d-recon; sid:1948; rev:8;)
Uncomment lines 23 and 24.
root@darkstar:rules# vi +23 dns.rules
Configure Oinkmaster to enable the rules during every update. Oinkmaster uses
the SID to determine which rules should be enabled. Add a comment to each
entry to help identify the SID. I list the revision of the rule when I create
the entry. The rule may change at a later date. The revision information may
help troubleshoot any possible problems with an updated rule. It's a good
idea to review the enablesid and disablesid entries every month or so. If a
rule was disabled because of false positives, a new revision of that rule may
have eliminated the problem.
root@darkstar:rules# vi /etc/oinkmaster.conf
enablesid 255 # DNS zone transfer TCP, rev 15
enablesid 1948 # DNS zone transfer UDP, rev 8
If the "MULTICAST_NET" variable was added to snort.conf, modify the follow rule
during updates.
root@darkstar:~# vi /etc/oinkmaster.conf
modifysid 2189 "->\s*any" | "-> !\$MULTICAST_NET" # IP Proto 103, rev 4
To disable rules, comment out the rule in the appropriate file. To ensure
Oinkmaster does not enable the rule when rules are updated, add a "disablesid"
line to the Oinkmaster configuration file.
root@darkstar:~# vi /etc/oinkmaster.conf
disablesid 376 # ICMP PING Microsoft Windows, rev 7
An alternative to editing the oinkmaster.conf file is to run makesidex.pl
everytime a rules is disabled.
root@darkstar:~# makesidex.pl /etc/snort/rules > /etc/snort/disablesid.conf
root@darkstar:~# oinkmaster.pl -C /etc/oinkmaster.conf \
-C /etc/snort/disablesid.conf -o /etc/snort/rules
To enable all of the rules, even the ones that are disabled by default:
root@darkstar:~# oinkmaster.pl -e -o /etc/snort/rules
--[ Configure SSH ]--
Make a few changes to the SSH server:
root@darkstar:~# vi /etc/ssh/sshd_config
Protocol 2
PermitRootLogin no
The following are already set by default. If it makes you feel better, add
them to the configuration file:
PermitEmptyPasswords no
UsePrivilegeSeparation yes
StrictMode yes
SyslogFacility AUTH
LogLevel INFO
Restart SSH so the changes take effect:
root@darkstar:~# /etc/rc.d/rc.sshd restart
--[ mod_security Installation ]--
From the webpage for ModSecurity, "ModSecurity is a web application firewall
that can work either embedded or as a reverse proxy. It provides protection
from a range of attacks against web applications and allows for HTTP traffic
monitoring, logging and real-time analysis."
dentonj@darkstar:downloads$ wget http://www.modsecurity.org/download/modsecu
rity-apache_2.1.1.tar.gz
dentonj@darkstar:downloads$ wget http://www.modsecurity.org/download/modsecu
rity-apache_2.1.1.tar.gz.md5
dentonj@darkstar:downloads$ wget http://www.modsecurity.org/download/modsecu
rity-core-rules_2.1-1.4.tar.gz
dentonj@darkstar:downloads$ md5sum modsecurity-apache_2.1.1.tar.gz
ab74ed5f320ffc4ed9f56487bf17c670 modsecurity-apache_2.1.1.tar.gz
dentonj@darkstar:downloads$ cat modsecurity-apache_2.1.1.tar.gz.md5
ab74ed5f320ffc4ed9f56487bf17c670 /home/ivanr/work/mod_security/build/modsec
urity-apache_2.1.1.tar.gz
dentonj@darkstar:downloads$ echo "Hi ivanr"
dentonj@darkstar:downloads$ cd ../src
dentonj@darkstar:src$ gzip -cd ../downloads/modsecurity-apache_2.1.1.tar.gz
| tar xf -
dentonj@darkstar:src$ cd modsecurity_2.1.1/apache2
Before compiling ModSecurity, change the following:
dentonj@darkstar:apache2$ vi Makefile
top_dir = /usr/lib/httpd
#DEFS = -DWITH_LIBXML2
dentonj@darkstar:apache2$ make
dentonj@darkstar:apache2$ su
root@darkstar:apache2# make install
root@darkstar:apache2# mkdir /etc/httpd/modsecurity
root@darkstar:apache2# cd /etc/httpd/modsecurity
root@darkstar:modsecurity# gzip -cd /home/dentonj/downloads/modsecurity-core
-rules_2.1-1.4.tar.gz | tar xf -
Change the configuration file for the web server to load the ModSecurity
module and the ModSecurity configuration files:
root@darkstar:rules# vi /etc/httpd/httpd.conf
LoadModule security2_module lib/httpd/modules/mod_security2.so
Include /etc/httpd/modsecurity/*.conf
One of the features is to mask the server identify. Before this feature can
work, the ServerTokens directive for Apache needs to be set to Full. Add the
following:
root@darkstar:~# vi /etc/httpd/httpd.conf
ServerTokens Full
Restart the web server so the configuration changes take effect:
root@darkstar:~# /etc/rc.d/rc.httpd restart
Configure and create the log files for ModSecurity. Logrotate is setup to look
for "/var/log/httpd/*_log".
root@darkstar:rules# vi modsecurity_crs_10_config.conf
SecAuditLog /var/log/httpd/modsec_audit_log
SecDebugLog /var/log/httpd/modsec_debug_log
root@darkstar:rules# touch /var/log/httpd/modsec_audit_log
root@darkstar:rules# touch /var/log/httpd/modsec_debug_log
Since a DNS entry is not going to be configured for the Snort sensor, the web
browser will have to use the IP address when connecting to the web server. One
of the ModSecurity rules will trigger when this happens. Comment out the
following to prevent this alert from filling up the logs:
root@darkstar:rules# cd /etc/httpd/modsecurity
root@darkstar:modsecurity# vi modsecurity_crs_21_protocol_anomalies.conf
#SecRule REQUEST_HEADERS:Host "^[\d\.]+$" "deny,log,auditlog,status:400,
msg:'Host header is a numeric IP address', severity:'2',id:'960017'"
id:'960015'
--[ OSSEC Installation ]--
From the webpage for OSSEC, "OSSEC is an Open Source Host-based Intrusion
Detection System. It performs log analysis, integrity checking, Windows
registry monitoring, rootkit detection, real-time alerting and active
response."
dentonj@darkstar:downloads$ wget http://www.ossec.net/files/ossec-hids-1.3.t
ar.gz
dentonj@darkstar:downloads$ cd ../src
dentonj@darkstar:src$ gzip -cd ../downloads/ossec-hids-1.3.tar.gz | tar xf -
dentonj@darkstar:src$ cd ossec-hids-1.3
dentonj@darkstar:ossec-hids-1.3$ su
root@darkstar:ossec-hids-1.3# ./install.sh
For installation in English, choose [en]. en
Press ENTER to continue
What kind of installation do you want? server
Choose where to install the OSSEC HIDS: /var/ossec
Do you want e-mail notifications? y
What's your e-mail address? root@localhost
We found your SMTP server as: 127.0.0.1 Do you want to use it? y
Do you want to run the integrity check daemon? y
Do you want to run the rootkit detection engine? y
Do you want to enable active response? y
Do you want to enable remote syslog? y
Configure OSSEC to monitor the PHP, ModSecurity, and SSL log files. Add the
following:
root@darkstar:~# vi /var/ossec/etc/ossec.conf
<localfile>
<log_format>syslog</log_format>
<location>/var/log/httpd/php_error_log</location>
</localfile>
<localfile>
<log_format>syslog</log_format>
<location>/var/log/httpd/modsec_audit_log</location>
</localfile>
<localfile>
<log_format>syslog</log_format>
<location>/var/log/httpd/modsec_debug_log</location>
</localfile>
<localfile>
<log_format>apache</log_format>
<location>/var/log/httpd/ssl_request_log</location>
</localfile>
OSSEC will parse syslog files looking for key words. One of the words that it
looks for, "bad", can be displayed by Snort during startup. An example message
is "Bad Payload Size Alert: ENABLED". To prevent Snort from triggering this
alert in OSSEC, change the following from:
root@darkstar:~# vi /var/ossec/rules/syslog_rules.xml
<rule id="1002" level="7">
<match>$BAD_WORDS</match>
<description>Unknown problem somewhere in the system.</description>
</rule>
To:
<rule id="1002" level="7">
<regex>$BAD_WORDS</regex>
<if_matched_regex>!snort</if_matched_regex>
<description>Unknown problem somewhere in the system.</description>
</rule>
OSSEC will look for network interfaces that go into promiscuous mode. Snort
will place the listening interface in promiscuous mode everytime is starts. To
prevent Snort from triggering this alert in OSSEC, change the following from:
root@darkstar:~# vi /var/ossec/rules/syslog_rules.xml
<rule id="5104" level="8">
<if_sid>5100</if_sid>
<regex>Promiscuous mode enabled|</regex>
<regex>device \S+ entered promiscuous mode</regex>
<description>Interface entered in promiscuous(sniffing) mode.</descr
iption>
<group>promisc,</group>
</rule>
To:
<!-- <rule id="5104" level="8">
<if_sid>5100</if_sid>
<regex>Promiscuous mode enabled|</regex>
<regex>device \S+ entered promiscuous mode</regex>
<description>Interface entered in promiscuous(sniffing) mode.</descr
iption>
<group>promisc,</group>
</rule> -->
Add an agent to be monitored. An encryption key will be created to encrypt
communications between the OSSEC server and the agent.
root@darkstar:~# /var/ossec/bin/manage_agents
****************************************
* OSSEC HIDS v1.3 Agent manager. *
* The following options are available: *
****************************************
(A)dd an agent (A).
(E)xtract key for an agent (E).
(L)ist already added agents (L).
(R)emove an agent (R).
(Q)uit.
Choose your action: A,E,L,R or Q: a
- Adding a new agent (use '\q' to return to the main menu).
Please provide the following:
* A name for the new agent: linuxclient
* The IP Address of the new agent: 192.168.1.27
* An ID for the new agent[001]:
Agent information:
ID:001
Name:linuxclient
IP Address:192.168.1.27
Confirm adding it?(y/n): y
Agent added.
****************************************
* OSSEC HIDS v1.3 Agent manager. *
* The following options are available: *
****************************************
(A)dd an agent (A).
(E)xtract key for an agent (E).
(L)ist already added agents (L).
(R)emove an agent (R).
(Q)uit.
Choose your action: A,E,L,R or Q: e
Available agents:
ID: 001, Name: linuxclient, IP: 192.168.1.27
Provide the ID of the agent to extract the key (or '\q' to quit): 001
Agent key information for '001' is:
GetYourOwnKeyMDAxIGRlYXRoc5MDk1NA==
** Press ENTER to return to the main menu.
****************************************
* OSSEC HIDS v1.3 Agent manager. *
* The following options are available: *
****************************************
(A)dd an agent (A).
(E)xtract key for an agent (E).
(L)ist already added agents (L).
(R)emove an agent (R).
(Q)uit.
Choose your action: A,E,L,R or Q: q
** You must restart the server for your changes to have effect.
Install the OSSEC agent on a computer that is going to be monitored.
nick@linuxclient:downloads$ wget http://www.ossec.net/files/ossec-hids-1.3.t
ar.gz
nick@linuxclient:downloads$ cd ../src
nick@linuxclient:src$ gzip -cd ../downloads/ossec-hids-1.3.tar.gz | tar xf -
nick@linuxclient:src$ cd ossec-hids-1.3
nick@linuxclient:ossec-hids-1.3$ su
root@linuxclient:ossec-hids-1.3# ./install.sh
For installation in English, choose [en]. en
Press ENTER to continue
What kind of installation do you want? server
Choose where to install the OSSEC HIDS: /var/ossec
What's the IP Address of the OSSEC HIDS server? 192.168.1.2
Do you want to run the integrity check daemon? y
Do you want to run the rootkit detection engine? y
Do you want to enable active response? y
Import the key generated by the server:
root@linuxclient:~# /var/ossec/bin/manage_agents
****************************************
* OSSEC HIDS v1.3 Agent manager. *
* The following options are available: *
****************************************
(I)mport key from the server (I).
(Q)uit.
Choose your action: I or Q: i
* Provide the Key generated by the server.
* The best approach is to cut and paste it.
*** OBS: Do not include spaces or new lines.
Paste it here (or '\q' to quit): GetYourOwnKeyMDAxIGRlYXRoc5MDk1NA==
Agent information:
ID:001
Name:linuxclient
IP Address:192.168.1.27
Confirm adding it?(y/n): y
Added.
** Press ENTER to return to the main menu.
Restart the OSSEC server and agent.
root@darkstar:~# /var/ossec/bin/ossec-control restart
root@linuxclient:~# /vaar/ossec/bin/ossec-control restart
Check the status of the agent.
root@darkstar:~# /var/ossec/bin/list_agents -a
linuxclient-192.168.1.27 is available.
--[ LogWatch Installation ]--
Install LogWatch to monitor the system and the logs for abnormal behavior.
Yes, OSSEC is installed for this purpose. Yes, installing LogWatch is
redundant. It's a good idea anyways.
dentonj@darkstar:downloads$ wget ftp://ftp.kaybee.org/pub/linux/logwatch-7.3
.6.tar.gz
dentonj@darkstar:downloads$ cd ../src
dentonj@darkstar:src$ gzip -cd ../downloads/logwatch-7.3.6.tar.gz | tar xf -
dentonj@darkstar:src$ cd logwatch-7.3.6
dentonj@darkstar:logwatch-7.3.6$ su
root@darkstar:logwatch-7.3.6# chmod 700 install_logwatch.sh
root@darkstar:logwatch-7.3.6# ./install_logwatch.sh
Enter the path to the Logwatch BaseDir: Use Default
Enter the path for the Logwatch ConfigDir: Use Default
Enter the dir name to be used for temp files: Use Default
Enter the location of perl: Use Default
Enter the dir name to used for the manpage: /usr/man
Configure LogWatch:
root@darkstar:~# cd /usr/share/logwatch/default.conf
root@darkstar:default.conf# cp -R * /etc/logwatch/conf
root@darkstar:default.conf# cd ../scripts
root@darkstar:scripts# cp -R * /etc/logwatch/scripts
root@darkstar:scripts# vi /etc/logwatch/conf/logwatch.conf
Print = No
Detail = High
#Service = "-zz-network"
#Service = "-zz-sys"
#Service = "-eximstats"
--[ Increase system log retention ]--
By default, system logs are only maintained for 4 weeks. Login logs are only
retained for an extra month. Change the log retention to one year:
root@darkstar:~# vi /etc/logrotate.conf
compress
rotate 52
/var/log/wtmp {
monthly
create 0664 root utmp
rotate 12
}
/var/log/btmp {
monthly
create 0600 root root
rotate 12
}
root@darkstar:~# vi /etc/logrotate.d/httpd
rotate 52
--[ Keep the system clock synced ]--
root@darkstar:~# vi /etc/cron.daily/ntpdate
#!/bin/sh
/usr/sbin/ntpdate clock.via.net && /sbin/hwclock --systohc
root@darkstar:~# chmod 700 /etc/cron.daily/ntpdate
--[ Optimize the kernel ]--
The file /etc/sysctl.conf is called by /etc/rc.d/rc.S. However, the file does
not exist by default. Create the file and add the following:
root@darkstar:~# vi /etc/sysctl.conf
net.core.netdev_max_backlog = 2500
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 87380 16777216
net.ipv4.tcp_no_metrics_save = 1
Look at http://www-didc.lbl.gov/TCP-tuning/linux.html for more information.
--[ Optimize the network interface ]--
Change the rx ring parameters for the interface. Run the following to get the
current settings.
root@darkstar:~# ethtool -g eth0
Look at the "RX" settings. If the current setting is lower than the pre-set
maximum, run the following command, replacing 512 with the maximum:
root@darkstar:~# ethtool -G eth0 rx 512
root@darkstar:~# vi /etc/rc.d/rc.local
/usr/sbin/ethtool -G eth0 rx 512
--[ Optimizing MySQL ]--
Some of the configuration changes that have already been made were to increase
the performance of MySQL. On busy networks, the tables in the Snort database
can quickly become fragmented. I run the following SQL script once a week to
optimize the tables. Since a password is require, I do not use cron to run
this script.
root@darkstar:~# vi optimize_snort.sql
optimize table acid_ag;
optimize table acid_ag_alert;
optimize table acid_event;
optimize table acid_ip_cache;
optimize table base_roles;
optimize table base_users;
optimize table data;
optimize table detail;
optimize table encoding;
optimize table event;
optimize table icmphdr;
optimize table iphdr;
optimize table opt;
optimize table reference;
optimize table reference_system;
optimize table schema;
optimize table sensor;
optimize table sig_class;
optimize table sig_reference;
optimize table signature;
optimize table tcphdr;
optimize table udphdr;
root@darkstar:~# mysql -p snort < optimize_snort.sql
--[ Start Snort and Barnyard ]--
Start Snort and Barnyard:
root@darkstar:~# /etc/rc.d/rc.snort start
root@darkstar:~# /etc/rc.d/rc.barnyard start
Verify Snort and Barnyard are running:
root@darkstar:~# ps auxww | grep snort
root@darkstar:~# ps auxww | grep barnyard
If either one is not running, check the logs to determine the problem:
root@darkstar:~# less /var/log/messages
root@darkstar:~# less /var/log/syslog
If Barnyard seems to start, but then exits without an error, comment out the
"config daemon" line in the configuration file. Start Barnyard and look for
any errors.
After everything is working properly, change rc.local so Snort and Barnyard
starts during bootup:
root@darkstar:~# vi /etc/rc.d/rc.local
if [ -x /etc/rc.d/rc.snort ]; then
/etc/rc.d/rc.snort start
fi
if [ -x /etc/rc.d/rc.barnyard ]; then
/etc/rc.d/rc.barnyard start
fi
--[ NTOP Installation ]--
From the webpage for ntop, "ntop is a network traffic probe that shows the
network usage, similar to what the popular top Unix command does."
Before ntop can be installed, rrdtool must be installed.
dentonj@darkstar:downloads$ wget http://oss.oetiker.ch/rrdtool/pub/rrdtool-1
.2.23.tar.gz
dentonj@darkstar:downloads$ cd ../src
dentonj@darkstar:src$ gzip -cd ../downloads/rrdtool-1.2.23.tar.gz | tar xf -
dentonj@darkstar:src$ cd rrdtool-1.2.23
dentonj@darkstar:rrdtool-1.2.23$ ./configure
dentonj@darkstar:rrdtool-1.2.23$ make
dentonj@darkstar:rrdtool-1.2.23$ su
root@darkstar:rrdtool-1.2.23# make install
root@darkstar:rrdtool-1.2.23# cd /usr/local
root@darkstar:local# ln -s rrdtool-1.2.23 rrdtool
Download and install ntop.
dentonj@darkstar:downloads$ wget http://easynews.dl.sourceforge.net/sourcefo
rge/ntop/ntop-3.3.tar.gz
dentonj@darkstar:downloads$ cd ../src
dentonj@darkstar:src$ gzip -cd ../downloads/ntop-3.3.tar.gz | tar xf -
dentonj@darkstar:src$ cd ntop-3.3
dentonj@darkstar:ntop-3.3$ ./autogen.sh
dentonj@darkstar:ntop-3.3$ make
dentonj@darkstar:ntop-3.3$ su
root@darkstar:ntop-3.3# make install
Create a user account that ntop will use while running.
root@darkstar:ntop-3.3# groupadd ntop
root@darkstar:ntop-3.3# useradd -g ntop ntop -s /bin/false
root@darkstar:ntop-3.3# chown -R ntop.ntop /usr/local/share/ntop
Copy files that will need to be used by ntop to the configuration directory.
root@darkstar:ntop-3.3# mkdir /etc/ntop
root@darkstar:ntop-3.3# cp etter.finger.os.gz /etc/ntop
root@darkstar:ntop-3.3# cp oui.txt.gz /etc/ntop
root@darkstar:ntop-3.3# cp specialMAC.txt.gz /etc/ntop
root@darkstar:ntop-3.3# cp ntop-cert.pem /etc/ntop
root@darkstar:ntop-3.3# cp p2c.opt.table.gz /etc/ntop
root@darkstar:ntop-3.3# mkdir /var/ntop
root@darkstar:ntop-3.3# cp packages/debian.official/protocol.list /usr/local
/share/ntop/
root@darkstar:ntop-3.3# cp ntop.8 /usr/local/man/man8/
Copy the configuration file for ntop to the configuration directory.
root@darkstar:ntop-3.3# cp packages/RedHat/ntop.conf.sample /etc/ntop.conf
Configure ntop:
root@darkstar:ntop-3.3# vi /etc/ntop.conf
--interface eth0
--https-server 3001
#--daemon
--use-syslog=daemon
--no-mac
Set a password for ntop:
root@darkstar:ntop-3.3# /usr/local/bin/ntop @/etc/ntop.conf -A
Configure ntop to run in daemon mode:
root@darkstar:ntop-3.3# vi /etc/ntop.conf
--daemon
Create the startup script to start ntop:
root@darkstar:ntop-3.3# vi /etc/rc.d/rc.ntop
#!/bin/sh
#
# Start/Stop/Restart NTOP
#
# Basic checks
[ -x "/usr/local/bin/ntop" ] || exit 1
[ -r "/etc/ntop.conf" ] || exit 1
[ -r "/var/ntop/ntop_pw.db" ] || exit 1
ntop_start() {
echo "Starting NTOP..."
/usr/local/bin/ntop -d -L @/etc/ntop.conf
}
ntop_stop() {
echo "Stopping NTOP..."
/bin/killall ntop
}
ntop_restart() {
ntop_stop
/usr/bin/sleep 2
ntop_start
}
case "$1" in
'start')
ntop_start
;;
'stop')
ntop_stop
;;
'restart')
ntop_restart
;;
*)
echo "usage $0 start|stop|restart"
esac
root@darkstar:ntop-3.3# chmod 700 /etc/rc.d/rc.ntop
root@darkstar:ntop-3.3# /etc/rc.d/rc.ntop start
Change rc.local so NTOP starts during bootup:
root@darkstar:ntop-3.3# vi /etc/rc.d/rc.local
if [ -x /etc/rc.d/rc.ntop ]; then
/etc/rc.d/rc.ntop start
fi
--[ Stunnel ]--
Stunnel should already be installed with Slackware. To verify Stunnel is
installed:
root@darkstar:~# stunnel -version
On the server (the system running MySQL):
Create the Stunnel configuration file:
root@darkstar:~# vi /etc/stunnel/stunnel.conf
;
; stunnel.conf
;
cert = /etc/stunnel/stunnel.pem
pid = /var/run/stunnel.pid
client = no
[3306]
accept = 3307
connect = 3306
Generate a new stunnel.pem key. Answer the question appropriately:
root@darkstar:~# cd /etc/stunnel && ./generate-stunnel-key.sh
Generating a 1024 bit RSA private key
.....++++++
............................++++++
writing new private key to 'stunnel.pem'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or
a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [PL]:US
State or Province Name (full name) [Some-State]:Arizona
Locality Name (eg, city) []:Sierra Vista
Organization Name (eg, company) []: Cochiselinux
Organizational Unit Name (eg, section) []:
Common Name (FQDN of your server) [localhost]:
subject= /C=US/ST=Arizona/L=Sierra Vista/O=Cochiselinux/CN=localhost
notBefore=Aug 23 14:14:21 2007 GMT
notAfter=Aug 22 14:14:21 2008 GMT
SHA1 Fingerprint=A0:CA:38:AA:B4:5E:2E:7C:A2:F9:82:24
Modify the sensor table in the snort database:
root@darkstar:~# mysql -p
mysql> insert into snort.sensor (sid,hostname,interface,filter,detail,encodi
ng,last_cid) values (2,"192.168.1.27","eth1","",1,0,0);
mysql> select * from snort.sensor;
+-----+--------------+-----------+--------+--------+----------+----------+
| sid | hostname | interface | filter | detail | encoding | last_cid |
+-----+--------------+-----------+--------+--------+----------+----------+
| 1 | localhost | eth1 | | 1 | 0 | 2969 |
| 2 | 192.168.1.27 | eth1 | | 1 | 0 | 0 |
+-----+--------------+-----------+--------+--------+----------+----------+
2 rows in set (0.00 sec)
Create the startup script for Stunnel:
root@darkstar:~# vi /etc/rc.d/rc.stunnel
#!/bin/sh
#
# Stop/Restart Stunnel
#
stunnel_start() {
echo "Starting stunnel..."
/usr/sbin/stunnel /etc/stunnel/stunnel.conf
}
stunnel_stop() {
echo "Stopping stunnel..."
/bin/killall stunnel
}
stunnel_restart() {
stunnel_stop
/usr/bin/sleep 2
stunnel_start
}
case "$1" in
'start')
stunnel_start
;;
'stop')
stunnel_stop
;;
'restart')
stunnel_restart
;;
*)
echo "usage $0 start|stop|restart"
esac
root@darkstar:~# chmod 700 /etc/rc.d/rc.stunnel
root@darkstar:~# vi /etc/rc.d/rc.local
if [ -x /etc/rc.d/rc.stunnel ]; then
/etc/rc.d/rc.stunnel start
fi
root@darkstar:~# /etc/rc.d/rc.stunnel start
On the client:
Install and configure Snort
Install and configure Barnyard
Install and configure Oinkmaster
Install and configure Logwatch
Configure the firewall
Configure the kernel
Configure Logrotate
Install and configure OSSEC Agent
Create the Stunnel configuration file:
root@snortsensor:~# vi /etc/stunnel/stunnel.conf
;
; stunnel.conf
;
pid = /var/run/stunnel.pid
client = yes
[3307]
accept = 3306
connect = 192.168.1.2:3307
Create the startup script for Stunnel:
root@snortsensor:~# vi /etc/rc.d/rc.stunnel
Use the same file as the server.
root@darkstar:~# chmod 700 /etc/rc.d/rc.stunnel
root@darkstar:~# vi /etc/rc.d/rc.local
if [ -x /etc/rc.d/rc.stunnel ]; then
/etc/rc.d/rc.stunnel start
fi
Test the Stunnel connection:
root@snortsensor:~# openssl s_client -connect 192.168.1.2:3307
CONNECTED(00000003)
depth=0 /C=US/ST=Arizona/L=Sierra Vista/O=Cochiselinux/CN=localhost
verify error:num=18:self signed certificate
verify return:1
depth=0 /C=US/ST=Arizona/L=Sierra Vista/O=Cochiselinux/CN=localhost
verify return:1
---
Certificate chain
0 s:/C=US/ST=Arizona/L=Sierra Vista/O=Cochiselinux/CN=localhost
i:/C=US/ST=Arizona/L=Sierra Vista/O=Cochiselinux/CN=localhost
---
Server certificate
-----BEGIN CERTIFICATE-----
MIICaTCCAdKgAwIBAgIJAONNMRMSpxQqMA0GCSqGSIb3DQEBBQUAMGsxCzAJBgNV
BAYTAlVTMRAwDgYDVQQIEwdBcml6b25hMRUwEwYDVQQHEwxTaWVycmEgVmlzdGEx
HzAdBgNVBAoTFlN0dW5uZWwgRGV2ZWxvcGVycyBMdGQxEjAQBgNVBAMTCWxvY2Fs
-----END CERTIFICATE-----
subject=/C=US/ST=Arizona/L=Sierra Vista/O=Cochiselinux/CN=localhost
issuer=/C=US/ST=Arizona/L=Sierra Vista/O=Cochiselinux/CN=localhost
---
No client certificate CA names sent
---
SSL handshake has read 783 bytes and written 316 bytes
---
New, TLSv1/SSLv3, Cipher is AES256-SHA
Server public key is 1024 bit
Compression: NONE
Expansion: NONE
SSL-Session:
Protocol : TLSv1
Cipher : AES256-SHA
Session-ID: E42CFF92027106F3FE0344EBFC9ED51800AB
Session-ID-ctx:
Master-Key: 7280027DEC46FF305EBECDA8225B43E191D2
Key-Arg : None
Start Time: 1190554391
Timeout : 300 (sec)
Verify return code: 18 (self signed certificate)
---
8
5.0.37-log=Ui1U<j!c,OB=LG_&@MCI%closed
Ensure that MySQL is not running on the client and start Stunnel:
root@snortsensor:~# /etc/rc.d/rc.mysql stop
root@snortsensor:~# chmod 600 /etc/rc.d/rc.mysql
root@snortsensor:~# /etc/rc.d/rc.stunnel start
Configure the output for Barnyard. Specify the IP that the client is using
with the "server" entry. Using "localhost" will cause Barnyard to attempt to
connect to "/var/run/mysql/mysql.sock". Since MySQL is not running on the
client, Barnyard will exit with an error.
root@snortsensor:~# vi /etc/snort/barnyard.conf
output log_acid_db: mysql, sensor_id 2, database snort, server 192.168.2
.27, user snort, detail full, password mysqlsnortpassword
If the line "config daemon" is commented out from "/etc/snort/barnyard.conf",
the following should be seen when starting Barnyard:
root@snortsensor:~# /etc/rc.d/rc.snort start
root@snortsensor:~# /etc/rc.d/rc.barnyard start
Starting Barnyard...
Barnyard Version 0.2.0 (Build 32)
Starting data processing using information from bookmark file
Opened spool file '/var/log/snort/snort.log.1190549663'
OpAcidDB configured
Database Flavour: mysql
Database Server: 192.168.1.27
Database User: snort
SensorID: 2
Next CID: 1
Waiting for new data
Use IPTraf to verify the Stunnel connection.
root@snortsensor:~# iptraf
192.168.1.2:3307 = 50205 7118351 -PA- eth0
192.168.1.27:54356 = 50696 18768688 --A- eth0
192.168.1.27:54355 = 101379 30158512 --A- lo
192.168.1.27:3306 = 100345 7899016 -PA- lo
On the server, verify the client is inserting entries in the snort database:
root@darkstar:~# mysql -p
mysql> select * from snort.sensor;
+-----+--------------+-----------+--------+--------+----------+----------+
| sid | hostname | interface | filter | detail | encoding | last_cid |
+-----+--------------+-----------+--------+--------+----------+----------+
| 1 | localhost | eth1 | | 1 | 0 | 64338 |
| 2 | 192.168.1.27 | eth1 | | 1 | 0 | 11002 |
+-----+--------------+-----------+--------+--------+----------+----------+
2 rows in set (0.00 sec)
To add another Snort sensor, repeat the above.
--[ When You Are Done ]--
Join the irc channel #slackware on irc.oftc.net and talk about everything
but Slackware.