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Lab 12.4.3 Configure Intrusion Detection

Estimated Time: 30 Minutes

Number of Team Members: Two teams with four students per team

Objective

In this lab exercise, students will complete the following tasks:

• Configure the use of Cisco Intrusion Detection System (IDS) information signatures and

send Cisco IDS Syslog output to a Syslog server.

• Configure the use of IDS attack signatures and send Cisco IDS Syslog output to a Syslog

server.

Scenario

The PIX Security Appliance is interoperable with the Cisco Intrusion Detection System (Cisco IDS).
The PIX Security Appliance traps IDS signatures and sends these as syslog messages to the Syslog
server. This feature supports only single-packet IDS signatures.

Topology

This figure illustrates the lab network environment.

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6 Fundamentals of Network Security v 1.1 - Lab 12.4.3 Copyright  2003, Cisco Systems, Inc.

Preparation

Begin with the standard lab topology and verify the standard configuration on the pod PIX Security
Appliances. Access the PIX Security Appliance console port using the terminal emulator on the
student PC. If desired, save the PIX Security Appliance configuration to a text file for later analysis.

Tools and Resources

In order to complete the lab, the standard lab topology is required:

•  Two pod PIX Security Appliances
•  Two student PCs
•  One SuperServer
•  Backbone switch and one backbone router
•  Two console cables
•  HyperTerminal

Additional materials:

Refer to Cisco PIX Security Appliance System Log Messages for a list of the supported IDS
signature messages. The documentation can be viewed online at the following website:

http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_61/syslog/index.htm

Additional information on configuring firewalls can be found in, Cisco Secure PIX Firewalls by David
Chapman and Andy Fox (ISBN 1587050358).

Command list

In this lab exercise, the following commands will be used. Refer to this list if assistance or help is
needed during the lab exercise.

Command

Description

ip audit interface

if_name audit_name

Configures IDS signature use. Configuration mode.

ip audit name audit_name

attack [action [alarm]

[drop] [reset]]

Configures IDS signature use. Configuration mode.

show ip audit info

Displays the default informational actions.

show ip audit interface

Displays the interface configuration.

show ip audit name [name

[info | attack]]

Displays all audit policies or specific policies
referenced by name and possibly type.

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Step 1 Configure the Use of Cisco IDS Signatures and to Send Cisco IDS Syslog Output to a
Syslog Server

Complete the following steps to configure the use of Cisco IDS signatures and to send Cisco IDS
Syslog output to a Syslog server:

a. Turn off console logging:

PixP(config)# no logging console debug

b. Turn on logging and send messages to the syslog server:

PixP(config)# logging on

PixP(config)# logging host inside 10.0.P.11

PixP(config)# logging trap debug

c. Verify connectivity by pinging the peer pod internal host from the Windows command prompt:

C:\>ping 192.168.Q.10

Pinging 192.168.Q.10 with 32 bytes of data:

Reply from 192.168.Q.10: bytes=32 time<10ms TTL=125

(where Q = peer pod number)

d. Specify the information signature policy on the PIX Security Appliance:

PixP(config)# ip audit name INFOPOLICY info action alarm reset

Note: The syntax for the ip audit command is:

ip audit name audit_name info [action [alarm] [drop] [reset]]

The alarm option indicates that when a signature match is detected in a packet, PIX Security
Appliance reports the event to all configured syslog servers. The drop option drops the offending
packet. The reset option drops the offending packet and closes the connection if it is part of an
active connection. The default is alarm.

e. Apply the information signature policy to the outside interface:

PixP(config)# ip audit interface outside INFOPOLICY

f. Verify the information signature policy on the PIX Security Appliance:

PixP(config)# show ip audit interface

ip audit interface outside INFOPOLICY

PixP(config)# show ip audit info

ip audit info action alarm

PixP(config)# show ip audit name

ip audit name INFOPOLICY info action alarm reset

PixP(config)#

g. Open and the Kiwi Syslog Daemon on the desktop.

h. Return to the Windows command line and attempt to ping the peer pod internal host. The ping

should fail.
C:\>ping 192.168.Q.10

Pinging 192.168.Q.10 with 32 bytes of data:

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Request timed out.

(where Q = peer pod number)

i. Observe the messages that appear on the Kiwi Syslog Daemon display. The log should be

similar to the following:

%PIX-4-400010: IDS:2000 ICMP echo reply from 192.168.Q.10 to

192.168.P.10 on interface outside

%PIX-4-400010: IDS:2000 ICMP echo reply from 192.168.Q.10 to

192.168.P.10 on interface outside

%PIX-4-400010: IDS:2000 ICMP echo reply from 192.168.Q.10 to

192.168.P.10 on interface outside

%PIX-4-400010: IDS:2000 ICMP echo reply from 192.168.Q.10 to

192.168.P.10 on interface outside

(where P = pod number, and Q = peer pod number)

j. Remove the information signature policy from the outside interface:

PixP(config)# no ip audit interface outside INFOPOLICY

k. Remove the audit policy audit_name:

PixP(config)# no ip audit name INFOPOLICY

l. Verify that the information signature policy has been removed from the outside interface, the

default informational actions have been restored, and the ip audit name has been removed:
PixP(config)# show ip audit interface

PixP(config)# show ip audit info

ip audit info action alarm

PixP(config)# show ip audit name

Step 2 Configure the Use of IDS Attack Signatures and Send IDS Syslog Output to a Syslog
Server

Complete the following steps to configure the use of IDS attack signatures and send IDS Syslog
output to a Syslog server:

a. Create a global statement for traffic destined to the DMZ server:

PixP(config)# global (dmz) 1 172.16.P.20-172.16.P.254 netmask

255.255.255.0

b. Ping the bastion host with an Internet Control Message Protocol (ICMP) packet size of 10000

from the Windows 2000 command line:

C:\>ping –l 10000 172.16.P.2

Pinging 172.16.P.2 with 10000 bytes of data:

Reply from 172.16.P.2: bytes=10000 time<10ms TTL=128

(where P = pod number)

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c. Specify an attack policy:

PixP(config)# ip audit name ATTACKPOLICY attack action alarm reset

d. Apply the attack policy to the inside interface:

PixP(config)# ip audit interface inside ATTACKPOLICY

e. Ping the bastion host with an ICMP packet size of 10000 from the Windows 2000 command line:

C:\>ping –l 10000 172.16.P.2

Pinging 172.16.P.2 with 10000 bytes of data:

Request timed out.

(where P = pod number)

f. Observe the messages that appear on the Kiwi Syslog Daemon display. The log should be

similar to the following:

%PIX-4-400025: IDS:2154 ICMP ping of death from 10.0.P.11 to 172.16.P.2

on interface inside