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Cisco Traffic Anomaly Detector Configuration Guide (Software Version 6.1)
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Index
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Preface
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Product Overview
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Intitializing the Detector
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Configuring the Detector
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Configuring Zones
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Configuring Zone Filters
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Configuring Policy Templates and Policies
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Learning Zone Traffic Characteristics
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Detecting Zone Traffic Anomalies
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Using Interactive Detect Mode
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Using Attack Reports
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Using Detector Diagnostic Tools
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Performing Maintenance Tasks
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Feedback
Table Of Contents
Using Detector Diagnostic Tools
Displaying the Detector Configuration
Using Counters to Analyze Traffic
Displaying Counters and Average Traffic Rates
Clearing Detector and Zone Counters
Configuring the Logging Parameters
Clearing the BIOS System Log File
Monitoring Network Traffic and Extracting Attack Signatures
Configuring the Detector to Automatically Record Traffic
Activating the Detector to Manually Record Traffic
Stopping the Detector from Manually Recording Traffic
Managing Packet-Dump Capture Files Disk Space
Displaying Manual Packet-Dump Settings
Displaying Automatic Packet-Dump Settings
Exporting Packet-Dump Capture Files Automatically
Exporting Packet-Dump Capture Files Manually
Importing Packet-Dump Capture Files
Displaying Packet-Dump Capture Files
Generating Attack Signatures from Packet-Dump Capture Files
Copying Packet-Dump Capture Files
Deleting Packet-Dump Capture Files
Displaying General Diagnostic Data
Configuring the Log and Report History
Displaying the CPU Utilization
Using Detector Diagnostic Tools
This chapter describes how to display statistics and diagnostics on the Cisco Traffic Anomaly Detector (Detector) and contains the following sections:
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Displaying the Detector Configuration
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Displaying the Detector Configuration
You can display the Detector configuration file, which includes information about the Detector configuration, such as interface IP addresses, default gateway addresses, and configured zones.
To display the Detector configuration file, use the following command:
show running-config [all | detector | interfaces interface-name | router | zones]
Table 11-1 provides the arguments and keywords for the show running-config command.
The following example shows how to display the Detector configuration file:
user@DETECTOR# show running-config detectorThe configuration file consists of the commands that you enter to configure the Detector with the current settings. You can export the Detector configuration file to a remote FTP server for backup purposes or for implementing the Detector configuration parameters on another Detector. See the "Displaying Detector Zones" section for more information.
Displaying Detector Zones
You can display an overview of the zones to see which zones are active and what their current status is by entering the show command in global mode.
Table 11-2 describes the possible operating states of a zone.
The following example shows how to display an overview of the Detector zones:
user@DETECTOR# showUsing Counters to Analyze Traffic
You can display Detector and zone counters to display information about the current traffic that the Detector is handling, analyze zone traffic, and perform monitoring tasks.
This section contains the following topics:
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Displaying Counters and Average Traffic Rates
To display the zone counters, use one of the following commands:
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To display the Detector counters, use the command in global or configuration mode.
To display the zone counters, use the command in one of the following command modes:
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The rate units are in bits per second (bps) and in packets per second (pps).
Note
The counter units are in packets and in kilobits. The counters are set to zero when you activate zone detection.
Table 11-3 displays the Detector counters.
The following example shows how to display the Detector average traffic rates:
user@DETECTOR-conf-zone-scannet# show ratesClearing Detector and Zone Counters
You can clear the Detector or zone counters if you are going to perform testing and want to be sure that the counters include information from the testing session only. The Detector clears the counters and the average traffic rates.
To clear the Detector counters, use the following command in global or configuration mode:
clear counters
The following example shows how to clear the Detector counters:
user@DETECTOR-conf# clear countersTo clear the zone counters, use one of the following commands:
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The following example shows how to clear the zone counters:
user@DETECTOR-conf-zone-scannet# clear countersDisplaying the Zone Status
To display an overview of the zone and its current status, use the show command in zone configuration mode. The overview includes the following information:
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See the "Configuring Zone Attributes" section on page 4-7 for more information.
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See the "Configuring Flex-Content Filters" section on page 5-2 and the "Configuring Dynamic Filters" section on page 5-13 for more information.
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See the "Using Counters to Analyze Traffic" section for more information.
The following example shows how to display the zone status:
user@DETECTOR-conf-zone-scannet# showManaging Detector Logs
The Detector automatically logs the system activity and events. You can display the Detector logs to review and track the Detector activity.
Table 11-4 displays the event log levels.
The log file displays all log levels (emergencies, alerts, critical, errors, warnings, notification, informational, and debugging). The Detector log file includes zone events with severity levels: emergencies, alerts, critical, errors, warnings, and notifications.
You can display the event log locally or from a remote server. This section contains the following topics:
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Configuring the Logging Parameters
To control the log file operations of the Detector, you can configure the logging parameters.
To configure the logging parameters, use the following command in configuration mode:
logging {device-log size logging-size-init | facility {local0 | local1 | local2 | local3 | local4 | local5 | local6 | local7} | host remote-syslog-server-ip | trap {alerts | critical | debugging | emergencies | errors | informational | notifications | warnings} | zone-log size logging-size-init}
Table 11-5 provides the keywords and arguments for the logging command:
Table 11-5 Keywords and Arguments for the logging Command
device-log size logging-size-init
Specifies the space allocated for all Detector log files. The maximum amount of space is 140 MB, which is the default setting.
facility
Specifies the export syslog facility. The remote syslog server uses logging facilities to filter events. For example, the logging facility allows the remote user to receive the Detector events in one file and use another file for events from other networking devices.
The available facilities are local0 through local7. The default is local4.
host remote-syslog-
server-ipSpecifies the remote syslog server IP address to use when exporting log files. Enter the IP address and subnet mask in dotted-decimal notation (for example, an IP address of 192.168.100.1 and a subnet mask of 255.255.255.0). See the "Exporting the Log File" for more information.
trap
Specifies the severity level of the syslog traps sent to the remote syslog. When you specify one of the lower severity levels, the event log includes the higher severity levels above it. For example, if the trap level is set to warning, then error, critical, alerts, and emergencies are also sent. The available trap levels from the highest to the lowest severity level are as follows:
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The default is notification. See Table 11-4 for more information.
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zone-log size logging-size-init
Specifies the space allocated for all log files of a zone. The maximum amount of space is 100 MB, which is the default setting.
To display the current settings of the logging parameters, use either of the following commands in the global or configuration modes:
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The following example shows how to allocate 6 MB of space for zone logs:
user@DETECTOR-conf# logging zone-log size 6Managing Online Event Logs
This section describes how to manage the Detector real-time logging of events and contains the following topics:
Displaying Online Event Logs
You can activate the Detector monitoring feature and display a real-time event log, which enables you to view the online logging of the Detector events. To display the online event logs, use the following command:
event monitor
The following example shows how to activate monitoring:
user@DETECTOR# event monitorThe screen constantly updates to show new events.
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Exporting Online Event Logs
You can export the Detector online event logs to display the Detector operations that are registered in the log file and to display the Detector events from a remote host while they are registered in the Detector log file. The Detector log file is exported using the syslog mechanism. You can export the Detector log file to several syslog servers and specify additional servers so that if one server goes offline, another server is available to receive messages.
Online Detector log export is applicable with a remote syslog server only. If a remote syslog server is not available, use the copy log command to export the Detector log information to a file.
The following is an example of a logging event:
Sep 11 16:34:40 10.4.4.4 cm: scannet, 5 threshold-tuning-start: Zone activation completed successfully.The system log message syntax is as follows:
event-date event-time Detector-IP-address software-daemon/module zone-name event-severity-level event-type event-description
To export online event logs, perform the following steps:
Step 1
logging {facility | trap}Table 11-6 provides the keywords for the logging command.
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Step 2
logging host remote-syslog-server-ip
The remote-syslog-server-ip argument specifies the remote syslog server IP address.
To build a list of syslog servers that receive logging messages, use the logging host command more than once.
The following example shows how to configure the Detector to send traps with a severity level that is higher than notification. The Detector sends the traps using the facility local3 to a syslog server with IP address 10.0.0.191:
user@DETECTOR-conf# logging facility local3user@DETECTOR-conf# logging trap notificationsuser@DETECTOR-conf# logging host 10.0.0.191To display the configuration that the Detector uses to export online event logs, use the show logging command or the show log export-ip command.
Managing the Log File
This section describes how to manage the Detector log file and contains the following topics:
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Displaying the Log File
You can display the Detector log for diagnostic or monitoring purposes. The Detector log file includes zone events with these severity levels: emergencies, alerts, critical, errors, warnings, and notification.
To display the Detector log, use the following command in global mode:
show log
The following example shows how to display the Detector log:
user@DETECTOR# show logYou can display a zone log to display events that relate to the specified zone only.
To display the zone log, use the show log command in zone configuration mode.
Exporting the Log File
You can export the Detector log file to a network server for monitoring or diagnostics by entering one of the following commands in global mode:
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Table 11-7 provides the arguments and keywords for the copy log command.
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Because SFTP and SCP rely on Secure Shell (SSH) for secure communication, if you do not configure the key that the Detector uses before you enter the copy command with the sftp or scp option, the Detector prompts you for the password. See the "Configuring the Keys for SFTP and SCP Connections" section on page 3-27 for more information about how to configure the key that the Detector uses for secure communication.
The following example shows how to export the Detector log file to an FTP server:
user@DETECTOR# copy log ftp 10.0.0.191 log.txt <user> <password>Clearing the Log File
You can clear the Detector or zone log file if it is large or if you are going to perform testing and want to be sure that the log file includes information from the testing session only.
To clear the zone log file of all entries, use the following command in zone configuration mode:
clear log
To clear the Detector or zone log file of all entries, use the following command in configuration mode:
clear [zone zone-name] log
The optional zone zone-name keyword and argument specify the zone name. The default is to clear the Detector log file.
The following example shows how to clear the Detector log:
user@DETECTOR-conf# clear logClearing the BIOS System Log File
The BIOS system log contains mainly hardware-related event messages, such as the number of times that the device was powered off or restarted. You can clear the BIOS system log by using the following command in configuration mode:
clear log bios
The following example shows how to clear the BIOS log:
user@DETECTOR-conf# clear log bios
Monitoring Network Traffic and Extracting Attack Signatures
You can configure the Detector to record traffic directly from the network through nonintrusive taps and create a database from the recorded traffic. By querying the recorded traffic database, you can analyze past events, generate signatures of an attack, or compare current network traffic patterns with traffic patterns that the Detector recorded previously under normal traffic conditions.
You can configure filters so that the Detector records only traffic that meets certain criteria or you can record all traffic data and filter the traffic that the Detector displays.
The Detector records the traffic in PCAP format, which is compressed and encoded by the gzip (GNU zip) program with an accompanying file in Extensible Markup Language (XML) format that describes the recorded data.
The Detector can analyze the recorded traffic to determine if there are any common patterns or signatures that appear in the payload of the recorded attack packets. The Detector can extract attack signatures from the recorded traffic. Using the attack signature, you can configure a flex-content filter to block all traffic containing packet payloads that match the signature.
The Detector can record traffic as follows:
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New packet-dump capture files replace previous files. To save the recorded traffic, export the packet-dump capture files to a network server before you activate the Detector to record traffic again.
You can activate only one manual packet-dump capture at a time for a zone, but you can activate the manual packet-dump capture and the automatic packet-dump capture simultaneously. The Detector can manually record traffic for up to 10 zones simultaneously.
The Detector allocates, by default, 5-GB disk space for the manual packet-dump capture files of all zones. The Detector can save up to 50-GB disk space for manual and automatic packet-dump capture files of all zones. You must delete old files to free the disk space for additional packet-dump capture files.
This section contains the following topics:
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Configuring the Detector to Automatically Record Traffic
You can activate the Detector to automatically record network traffic for troubleshooting network problems or analyzing attack traffic. By using packet-dump capture filters, you can configure the Detector to record only the traffic that meets the criteria that you specify. You can also record all traffic and apply packet-dump capture filters to the recorded traffic when you view it.
The Detector records traffic in a capture buffer. When the capture buffer size reaches 50 MB, or after 10 minutes have elapsed, the Detector saves the buffered information to a local file in a compressed format, clears the buffer, and then continues recording traffic.
Within a packet-dump capture file, the Detector provides an IP summarization, which is a summary of the most frequently detected source IP addresses (according to the volume of traffic).
The Detector applies a naming convention to automatic packet-dump capture files that provides information about when the Detector recorded the traffic and how it handled the traffic. Table 11-8 describes the sections of the automatic packet-dump capture filename.
When you enable the learning process or the detect and learning function, the Detector saves all of the packet-dump capture files that it creates. When you enable zone detection, the Detector saves one set of past packet-dump capture files only. To save all packet-dump capture files when zone detection is enabled, configure the Detector to automatically export the packet-dump capture files that it creates to a network server.
When you activate zone detection or activate the Detector to automatically record network traffic, the Detector erases all previous packet-dump capture files that it recorded during the detection process and creates new ones.
To configure the Detector to automatically record network traffic, perform the following steps:
Step 1
packet-dump auto-captureStep 2
See the "Configuring the Detector to Automatically Record Traffic" section.
The following example shows how to configure the Detector to automatically record zone traffic:
user@DETECTOR-conf-zone-scannet# packet-dump auto-captureTo stop the Detector from automatically capturing zone traffic data, use the no packet-dump auto-capture command.
To display the current packet-dump settings, use the show packet-dump command.
Activating the Detector to Manually Record Traffic
You can activate the Detector to start recording traffic so that you can record traffic during a specific period or change the criteria that the Detector uses to record the traffic.
The Detector stops recording traffic and saves the manual packet-dump capture to a file when the specified number of packets have been recorded or when either the learning process or zone detection have ended.
Within a packet-dump capture file, the Detector provides an IP summarization, which is a summary of the most frequently detected source IP addresses (according to the volume of traffic).
You can activate only one manual packet-dump capture at a time for a zone, but you can activate the manual packet-dump capture and the automatic packet-dump capture simultaneously. The Detector can record manual packet-dump captures for up to 10 zones simultaneously.
To activate a manual packet-dump capture, use the following command in zone configuration mode:
packet-dump capture [view] capture-name pdump-rate pdump-count [tcpdump-expression]
Note
Table 11-9 provides the arguments and keywords for the packet-dump command.
Table 11-9 Arguments and Keywords for the packet-dump Command
view
(Optional) Displays the traffic that the Detector is recording in real time.
capture-name
Name of the packet-dump capture file. Enter an alphanumeric string from 1 to 63 characters. The string can contain underscores but cannot contain spaces.
pdump-rate
Sample rate in packets per second. Enter a value from 1 to 10000.
Note
A packet-dump capture configured with a high sample-rate value consumes resources. We recommend that you use high-rate values cautiously because of the potential performance penalty.
pdump-count
Number of packets to record. When the Detector finishes recording the specified number of packets, it saves the manual packet-dump capture buffer to a file. Enter an integer from 1 to 5000.
tcpdump-expression
(Optional) Filter that you apply to specify the traffic to record. The Detector captures only traffic that complies with the filter expression. The expression rules are identical to the flex-content filter TCPDump expression rules. See the "Configuring the tcpdump-expression Syntax" section on page 5-5 for more information.
The following example shows how to activate a manual packet-dump capture to record 1000 packets with a sample rate of 10 pps and display the packets that are captured:
user@DETECTOR-conf-zone-scannet# packet-dump capture view 10 1000Stopping the Detector from Manually Recording Traffic
The Detector stops a manual packet-dump capture when it records the number of packets that you specified when you activated the capture. However, you can stop a manual packet-dump capture before the Detector records the specified number of packets by performing one of the following actions:
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no packet-dump capture capture-name
The capture-name argument specifies the name of the capture to stop.
The Detector saves the packet-dump capture file.
Managing Packet-Dump Capture Files Disk Space
By default, the Detector allocates 2 GB of disk space for the zone automatic packet-dump capture files. To modify the amount of disk space that the Detector allocates for the zone automatic packet-dump capture files, use the following command in zone configuration mode:
packet-dump disk-space disk-space
The disk-space argument specifies the amount of disk space that the Detector allocates for the zone automatic packet-dump capture files in megabytes. Enter an integer from 1 to 51200.
The following example shows how to configure the amount of disk space that the Detector allocates for the zone automatic packet-dump capture files:
user@DETECTOR-conf-zone-scannet# packet-dump disk-space 500The Detector saves past packet-dump capture files in PCAP format, which is compressed and encoded by the gzip (GNU zip) program.
See the "Displaying Manual Packet-Dump Settings" section for information about how to view the current amount of allocated disk space.
Displaying Manual Packet-Dump Settings
You can display the current amount of disk space that the Detector allocated for manual packet-dump capture files by using the show packet-dump command in configuration mode or in global mode. The Detector allocates a single block of disk space for the manual packet-dump capture files of all zones.
The following example shows how to display the current amount of disk space that the Detector allocated for manual packet-dump capture files:
user@DETECTOR-conf# show packet-dumpTable 11-10 describes the fields in the show packet-dump command output.
Displaying Automatic Packet-Dump Settings
You can display the current amount of disk space that is allocated for the zone automatic packet-dump capture files by using the show packet-dump command in zone configuration mode.
The following example shows how to display the current amount of disk space that is allocated for the zone automatic packet-dump capture files:
user@DETECTOR-conf-zone-scannet# show packet-dumpTable 11-11 describes the fields in the show packet-dump command output.
Exporting Packet-Dump Capture Files Automatically
You can configure the Detector to automatically export packet-dump capture files to a network server that uses FTP, SFTP, or SCP to transfer files. When you enable the automatic export function, the Detector exports the packet-dump capture files each time that it saves the contents of the packet-dump buffer to a local file. The Detector exports the packet-dump capture files in PCAP format, which is compressed and encoded by the gzip (GNU zip) program, with an accompanying file in XML format that describes the recorded data. The XML schema is described in the Capture.xsd file which you can download from the Software Center at http://www.cisco.com/public/sw-center/.
To configure the Detector to export packet-dump capture files automatically, use the following command in configuration mode:
export packet-dump file-server-name
The file-server-name argument specifies the name of a network server to which you export the files that you configure by using the file-server command. If you configure the network server for SFTP or SCP, you must configure the SSH key that the Detector uses for SFTP and SCP communication. See the "Exporting Files Automatically" section on page 12-6 for more information.
The following example shows how to automatically export packet-dump capture files:
user@DETECTOR-conf# export packet-dump Corp-FTP-ServerExporting Packet-Dump Capture Files Manually
You can manually export packet-dump capture files to a network server that uses FTP, SFTP, or SCP to transfer files. You can export a single packet-dump capture file or all packet-dump capture files of a specific zone. The Detector exports the packet-dump capture files in PCAP format, which is compressed and encoded by the gzip (GNU zip) program with an accompanying file in XML format that describes the recorded data. See the Capture.xsd file that accompanies the version for a description of the XML schema. You can download the xsd files that accompany the version from www.cisco.com.
To manually export packet-dump capture files to a network server, use one of the following commands in global mode:
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Table 11-12 provides the arguments and keywords for the copy zone packet-dump command.
Table 11-12 Arguments and Keywords for the copy zone packet-dump Command
zone zone-name
Specifies the name of an existing zone.
packet-dump captures
Exports packet-dump capture files.
capture-name
(Optional) Name of an existing packet-dump capture file. If you do not specify the name of a packet-dump capture file, the Detector exports all the zone packet-dump capture files. See the "Displaying Packet-Dump Capture Files" section for more information.
ftp
Specifies FTP.
sftp
Specifies SFTP.
scp
Specifies SCP.
server
IP address of the network server. Enter the IP address in dotted-decimal notation (for example, enter 192.168.10.2).
remote-path
Complete name of the path where the Detector saves the packet-dump capture files.
login
(Optional) Server login name. The login argument is optional when you define an FTP server. When you do not enter a login name, the FTP server assumes an anonymous login and does not prompt you for a password.
password
(Optional) Password for the remote FTP server. If you do not enter the password, the Detector prompts you for one.
file-server-name
Name of a network server. You must configure the network server using the file-server command.
If you configured the network server using SFTP or SCP, you must configure the SSH key that the Detector uses for SFTP and SCP communication.
See the "Exporting Files Automatically" section on page 12-6 for more information.
Because SFTP and SCP rely on SSH for secure communication, if you do not configure the key that the Detector uses before you enter the copy command with the sftp or scp option, the Detector prompts you for the password. See the "Configuring the Keys for SFTP and SCP Connections" section on page 3-27 for more information about how to configure the key that the Detector uses for secure communication.
The following example shows how to manually export the packet-dump capture files of zone scannet to FTP server 10.0.0.191:
user@DETECTOR# copy zone scannet packet-dump captures ftp 10.0.0.191 <user> <password>The following example shows how to manually export the packet-dump capture files of zone scannet to a network server that was defined by using the file-server command:
user@DETECTOR# copy zone scannet packet-dump captures cap-5-10-05 Corp-FTP-ServerImporting Packet-Dump Capture Files
You can import packet-dump capture files from a network server to the Detector so that you can analyze past events or compare current network traffic patterns with traffic patterns that the Detector previously recorded under normal traffic conditions. The Detector imports the packet-dump capture files in both XML and PCAP formats.
To import a packet-dump capture file, use one of the following commands in global mode:
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Table 11-13 provides the arguments and keywords for the copy zone packet-dump command.
Table 11-13 Arguments and Keywords for the copy zone packet-dump Command
ftp
Specifies FTP.
sftp
Specifies SFTP.
scp
Specifies SCP.
zone zone-name
Specifies the name of an existing zone for which the packet-dump capture files are imported.
captures
Imports packet-dump capture files.
server
IP address of the network server. Enter the IP address in dotted-decimal notation (for example, enter 192.168.10.2).
full-file-name
Complete path and filename, excluding the file extension, of the file to import. If you do not specify a path, the server copies the file from your home directory.
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login
(Optional) Server login name.
The login argument is optional when you define an FTP server. When you do not enter a login name, the FTP server assumes an anonymous login and does not prompt you for a password.
password
(Optional) Password for the FTP server. If you do not enter the password, the Detector prompts you for one.
file-server-name
Name of a network server. You must configure the network server using the file-server command.
If you configured the network server using SFTP or SCP, you must configure the SSH key that the Detector uses for SFTP and SCP communication.
See the "Exporting Files Automatically" section on page 12-6 for more information.
capture-name
Name of the file to import. The Detector appends the name of the file to the path that you defined for the network server by using the file-server command.
Because SFTP and SCP rely on SSH for secure communication, if you do not configure the key that the Detector uses before you enter the copy command with the sftp or scp option, the Detector prompts you for the password. See the "Configuring the Keys for SFTP and SCP Connections" section on page 3-27 for more information about how to configure the key that the Detector uses for secure communication.
The following example shows how to import packet-dump capture files of zone scannet from FTP server 10.0.0.191:
user@DETECTOR# copy ftp zone scannet packet-dump captures 10.0.0.191 /root/scannet/captures/capture-1 <user> <password>The following example shows how to import a packet-dump capture file from a network server:
user@DETECTOR# copy CorpFTP running-config capture-1Displaying Packet-Dump Capture Files
You can display either a list of packet-dump capture files or the contents of a single packet-dump capture file. By default, the Detector displays a list of all zone packet-dump capture files.
To display packet-dump capture files, use the following command in zone configuration mode:
show packet-dump captures [capture-name [tcpdump-expression]]
Table 11-14 provides the arguments for the show packet-dump captures command.
Table 11-14 Arguments for the show packet-dump captures Command
capture-name
(Optional) Name of an existing packet-dump capture file. If you do not specify the name of a packet-dump capture file, the Detector displays a list of all zone packet-dump capture files. See Table 11-15 for field descriptions of the command output. If you specify the name of a packet-dump capture file, the Detector displays the file in TCPDump format.
expression(Optional) Filter that the Detector uses when displaying the packet-dump capture file. The Detector displays only the portion of the packet-dump capture file that matches the filter criteria. The expression rules are identical to the flex-content filter TCPDump expression rules. See the "Configuring the tcpdump-expression Syntax" section on page 5-5 for more information.
The following example shows how to display the list of packet-dump capture files:
user@DETECTOR-conf-zone-scannet# show packet-dump capturesTable 11-15 describes the fields in the show packet-dump captures command output.
Table 11-15 Field Descriptions for the show packet-dump captures Command Output
Capture-name
Name of the packet-dump capture file. See Table 11-8 for a description of the automatic packet-dump capture filenames.
Size (MB)
Size of the packet-dump capture file in megabytes.
Filter
User-defined filter that the Detector used when recording traffic. The filter is in TCPDump format. The expression rules are identical to the flex-content filter TCPDump expression rules. See the "Configuring the tcpdump-expression Syntax" section on page 5-5 for more information.
Generating Attack Signatures from Packet-Dump Capture Files
An attack signature describes the common pattern that appears in the payload of attack packets. You can activate the Detector to generate the signature of attack traffic and then use this information to quickly identify future attacks of the same type. This feature allows you to detect new DDoS attacks and Internet worms even before signatures are published (for example, from antivirus software companies or mailing lists).
The Detector can generate an attack signature using the flex-content filter pattern expression syntax. You can use the attack signature in the flex-content filter pattern to filter out attack traffic. See the "Configuring Flex-Content Filters" section on page 5-2 for more information.
When you execute the attack signature generating process, you can determine the accuracy of the generated attack signature by specifying a reference packet-dump capture file containing clean (legitimate) traffic. After the Detector generates the attack signature from the packet-dump capture file containing malicious traffic, the Detector runs an analysis to determine how often the attack signature appears in the clean traffic of the reference packet-dump capture file. The Detector displays the results of the analysis as a percentage of the attack signature occurrences in the reference packet-dump capture file to the number of packets in the reference file. A percentage value that is less than 10% indicates that the attack signature is accurate and that you can use the signature to detect malicious traffic.
A percentage value that is greater than 10 percent indicates that the signature generating process failed. Do not use the signature to detect malicious traffic because it will result in the Detector wrongly identifying clean traffic as malicious traffic. The signature generating process may fail for the following reasons:
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To generate a signature of an attack, perform the following steps:
Step 1
See the "Activating the Detector to Manually Record Traffic" section for more information.
Step 2
See the "Displaying Packet-Dump Capture Files" section for more information.
Step 3
show packet-dump signatures capture-name [reference-capture-name]Table 11-16 provides the arguments for the show packet-dump signatures command.
Table 11-17 describes the fields in the show packet-dump signatures command output.
Table 11-17 Field Descriptions for the show packet-dump signatures Command Output
Start Offset
Offset (in bytes) from the beginning of the packet payload where the pattern begins. If you copy the pattern into the flex-content filter pattern expression, copy this offset into the flex-content filter start-offset argument.
End Offset
Offset (in bytes) from the beginning of the packet payload where the pattern ends. If you copy the pattern into the flex-content filter pattern expression, copy this offset into the flex-content filter end-offset argument.
Pattern
Signature that the Detector generated. The Detector generates the signature using the flex-content filter pattern expression syntax. See the "Configuring the pattern-expression Syntax" section on page 5-8 for more information. You can copy this pattern into the flex-content filter pattern expression.
Percentage
Percentage of the attack signature occurrences in the reference packet-dump capture file to the number of packets in the reference file.
The following example shows how to generate a signature from a manual packet-dump capture file:
user@DETECTOR-conf-zone-scannet# show packet-dump signatures PDumpCaptureCopying Packet-Dump Capture Files
You can copy a packet-dump capture file (or a portion of a file) under a new name. When you copy an automatic packet-dump capture file or a manual packet-dump capture file, the Detector saves them as manual files. If you want to save an existing automatic packet-dump capture file, you need to create a copy of it before the Detector overwrites the automatic packet-dump capture file with a new one.
You must manually delete packet-dump capture files if you need to free disk space. See the "Deleting Packet-Dump Capture Files" section for more information.
To copy a packet-dump capture file, use the following command in configuration mode:
copy zone zone-name packet-dump captures capture-name [tcpdump-expression] new-name
Table 11-18 provides the arguments and keywords for the copy zone packet-dump captures command.
Table 11-18 Arguments and Keywords for the copy zone packet-dump captures Command
zone-name
Name of an existing zone.
capture-name
Name of an existing packet-dump capture file.
tcpdump-expression
(Optional) Filter that the Detector uses to copy the packet-dump capture file. The Detector copies only the portion of the packet-dump capture file that matches the filter criteria. The expression rules are identical to the flex-content filter TCPDump expression rules. See the "Configuring the tcpdump-expression Syntax" section on page 5-5 for more information.
new-name
Name of the new packet-dump capture file.
The name is an alphanumeric string from 1 to 63 characters and can contain underscores but cannot contain spaces.
The following example shows how to copy a portion of the packet-dump capture file capture-1 that complies with the capture file under the name capture-2:
user@DETECTOR-conf# copy zone scannet capture-1 "tcp and dst port 80 and not src port 1000" capture-2Deleting Packet-Dump Capture Files
The Detector allocates by default, 5 GB of disk space for the manual packet-dump capture files of all zones. It can save up to 50 GB of manual and automatic packet-dump capture files of all zones. To free disk space for additional packet-dump capture files, delete the old ones.
You can save only one manual packet-dump capture file per zone and no more than 10 packet-dump capture files on the Detector. You must delete old manual packet-dump capture files to allow space for new files.
To delete automatic or manual packet-dump capture files, use one of the following commands:
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Table 11-19 provides the arguments and keywords for the clear packet-dump captures command.
The following example shows how to delete all manual packet-dump capture files:
user@DETECTOR-conf# clear packet-dump captures *Displaying General Diagnostic Data
You can display a general summary of the diagnostic data by using the following command:
show diagnostic-info [details]
The diagnostic data consists of the following information:
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The Detector has several LEDs that indicate inner operation status. These LEDs are normally off. When the LEDs are lit, they indicate hardware failure; the Detector sends a syslog message and an SNMP trap to inform the user of the problem.
Managing Disk Space
The Detector maintains activity logs and zone attack reports. If the disk usage is higher than 75 percent, or if you define a large number of zones on the Detector (over 500), we recommend that you decrease the file history parameters. When the used disk space reaches approximately 80 percent of the disk maximum capacity, the Detector displays a warning message in its syslog.
If the Detector displays a warning message, you can perform the following tasks:
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We recommend that you periodically store the Detector records on a network server, and then clear the logs.
Note
You can display the percentage of used disk space by using the following command in global mode:
show disk-usage
The following example shows how to display the percentage of used disk space:
user@DETECTOR# show disk-usage2%Configuring the Log and Report History
You can configure the length of time that the Detector records the logs and the attack reports of both the Detector and its zones. The Detector deletes old logs and reports.
You can configure the report and log history by using the following command:
history {logs | reports} days [enforce-now]
Table 11-20 provides the arguments and keywords for the history command.
Displaying Memory Consumption
The Detector displays the following information:
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The anomaly detection engine memory usage is affected by the number of active zones and the number of services that each zone monitors.
Note
To display the Detector memory consumption, use the following command:
show memory
The following example shows how to display the Detector memory consumption:
user@DETECTOR# show memorytotal used free shared buffers cachedIn KBytes: 2065188 146260 1918928 0 2360 69232Anomaly detection engine used memory: 0.3%
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Displaying the CPU Utilization
The Detector displays the percentage of CPU time in user mode, system mode, niced tasks (tasks with a nice value, which represents the priority of a process, that is negative), and idle. Niced tasks are counted in both system time and user time, so the total CPU utilization can be more than 100 percent.
To display the current percentage of CPU utilization, use the following command:
show cpu
The Detector displays the CPU utilization for both processors.
The following example shows how to display the current percentage of CPU utilization:
user@DETECTOR# show cpuHost CPU1: 0.0% user, 0.1% system, 0.1% nice, 98.0% idleHost CPU2: 0.0% user, 7.0% system, 0.0% nice, 92.0% idleMonitoring System Resources
You can display an overview of the resources that the Detector is using to help you analyze and monitor the system status by entering the following command in global or configuration mode:
show resources
The following example shows how to display the system resources:
user@DETECTOR# show resourcesTable 11-21 describes the fields in the show resources command output.
Table 11-21 Field Descriptions for the show resources Command Output
Host CPU1
Percentage of CPU time for CPU1 in user mode, system mode, niced tasks (tasks with a nice value, which represents the priority of a process, that is negative), and idle. Niced tasks are also counted in system time and user time so that the total CPU utilization can be more than 100 percent.
Host CPU2
Percentage of CPU time for CPU2 in user mode, system mode, niced tasks (tasks with a nice value, which represents the priority of a process, that is negative), and idle. Niced tasks are also counted in system time and user time so that the total CPU utilization can be more than 100 percent.
Disk space usage
Percentage of the allocated disk space that the Detector is using.
When the disk space usage reaches approximately 75 percent of the disk maximum capacity, the Detector displays a warning message in its syslog and sends a trap.
Disk space usage (continued)
Note
We recommend that you periodically store the Detector records on a network server and delete the old records.
If the disk space usage reaches 80 percent, you can perform the following tasks:
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Accelerator card memory usage
Percentage of memory that the accelerator card is using.
If the accelerator card memory usage is higher than 85 percent, the Detector generates an SNMP trap. A high value may indicate that the Detector is monitoring a high volume of traffic.
Accelerator card CPU utilization
Percentage of the accelerator card CPU utilization.
If the accelerator card CPU utilization is higher than 85 percent, the Detector generates an SNMP trap. A high value may indicate that the Detector is monitoring a high volume of traffic.
Anomaly detection engine used memory
Specifies the percentage of memory that the Detector statistical engine uses. The anomaly detection engine memory usage is affected by the number of active zones, the number of services each of the zones monitors, and the amount of nonspoofed traffic that the Detector is monitoring.
If the anomaly detection engine memory usage is higher than 95 percent, we strongly recommend that you lower the number of active zones.
Dynamic filters used
Total number of dynamic filters that are active in all the zones. The Detector displays the number of active dynamic filters and the percentage of dynamic filters that are active out of the total number of dynamic filters that the Detector supports, which is 150,000. If the number of active dynamic filters reaches 150,000, the Detector generates an SNMP trap with a severity level of EMERGENCY. If the number of active dynamic filters reaches 135,000, the Detector generates an SNMP trap with a severity level of WARNING.
A high value may indicate that the Detector is monitoring a high traffic volume of a DDoS attack.
For more information about the traps that the Detector generates, see Table 3-15 on page 3-29.
Managing the ARP Cache
You can display or manipulate the Address Resolution Protocol (ARP) cache to clear an address mapping entry or to manually define an address mapping entry. To manage the ARP cache, use one of the following commands:
arp [-evn] [-H type] [-i if] -a [hostname]
arp [-v] [-i if] -d hostname [pub]
arp [-v] [-H type] [-i if] -s hostname hw_addr [temp]
arp [-v] [-H type] [-i if] -s hostname hw_addr [netmask nm] pub
arp [-v] [-H type] [-i if] -Ds hostname ifa [netmask nm] pub
arp [-vnD] [-H type] [-i if] -f [filename]
Note
Table 11-22 provides the arguments and keywords for the arp command.
Caution
The following example shows how to display the ARP entries in default style:
user@DETECTOR# arp -eAddress HWtype HWaddress Flags Mask Iface10.10.1.254 ether 00:02:B3:C0:61:67 C eth110.10.8.11 ether 00:02:B3:45:B9:F1 C eth110.10.8.253 ether 00:D0:B7:46:72:37 C eth110.10.10.54 ether 00:03:47:A6:44:CA C eth1Displaying Network Statistics
You can display the host network connections, routing tables, interface statistics, and multicast memberships to debug network problems by entering one of the following commands:
netstat [address_family_options] [--tcp | -t] [--udp | -u] [--raw | -w] [--listening | -l] [--all | -a] [--numeric | -n] [--numeric-hosts] [--numeric-ports] [--numeric-users] [--symbolic | -N] [--extend | -e [--extend | -e]] [--timers | -o] [--program | -p] [--verbose | -v] [--continuous | -c] [delay]
netstat {--route | -r} [address_family_options] [--extend | -e [--extend | -e]] [--verbose | -v] [--numeric | -n] [--numeric-hosts] [--numeric-ports] [--numeric-users] [--continuous | -c] [delay]
netstat {--interfaces | -i} [iface] [--all | -a] [--extend | -e [--extend | -e]] [--verbose | -v] [--program | -p] [--numeric | -n] [--numeric-hosts] [--numeric-ports] [--numeric-users] [--continuous | -c] [delay]
netstat {--groups | -g} [--numeric | -n] [--numeric-hosts] [--numeric-ports] [--numeric-users] [--continuous | -c] [delay]
netstat {--masquerade | -M} [--extend | -e] [--numeric | -n] [--numeric-hosts] [--numeric-ports] [--numeric-users] [--continuous | -c] [delay]
netstat {--statistics | -s} [--tcp | -t] [--udp | -u] [--raw | -w] [delay]
netstat {--version | -V}
netstat {--help | -h}
Note
Table 11-23 provides arguments and keywords for the netstat command.
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Note
The following example shows how to display netstat information in verbose:
user@DETECTOR# netstat -vActive Internet connections (w/o servers)Proto Recv-Q Send-Q Local Address Foreign Address Statetcp 0 0 localhost:1111 localhost:32777 ESTABLISHEDtcp 0 0 localhost:8200 localhost:32772 ESTABLISHED...tcp 0 0 localhost:33464 localhost:8200 TIME_WAITtcp 1 0 localhost:1113 localhost:33194 CLOSE_WAIT...Active UNIX domain sockets (w/o servers)unix 2 [ ] STREAM CONNECTED 928unix 3 [ ] STREAM CONNECTED 890 /tmp/.zserv...user@DETECTOR#Using Traceroute
You can determine the route that packets take to arrive at a network host to debug network problems by entering the following command:
traceroute ip-address [-F] [-f first_ttl] [-g gateway] [-i iface]
[-m max_ttl] [-p port] [-q nqueries] [-s src_addr] [-t tos] [-w waittime] [packetlen]
Note
Table 11-24 provides the arguments and keywords for the traceroute command.
The following example shows how to trace the route to IP address 10.10.10.34:
user@DETECTOR# traceroute 10.10.10.34traceroute to 10.10.10.34 (10.10.10.34), 30 hops max, 38 byte packets1 10.10.10.34 (10.10.10.34) 0.577 ms 0.203 ms 0.149 msVerifying Connectivity
You can send ICMP ECHO_REQUEST packets to network hosts and verify connectivity by entering the following command:
ping ip-address [-c count] [-i interval] [-l preload] [-s packetsize] [-t ttl] [-w deadline] [-F flowlabel] [-I interface]
[-Q tos] [-T timestamp option] [-W timeout]Table 11-25 provides arguments and keywords for the ping command.
You can enter a maximum of 10 arguments and keywords in one command.
The following example shows how to send one ICMP ECHO_REQUEST packet to IP address 10.10.10.30:
user@DETECTOR# ping 10.10.10.30 -n 1Obtaining Debug Information
If the Detector experiences an operational problem, Cisco TAC may request that you send them a copy of the Detector internal debug information. The Detector debug core file contains information for troubleshooting Detector malfunctions. The file output is encrypted and intended for use by Cisco TAC personnel only.
To extract debug information to an FTP, SCP, or SFTP server, perform the following steps:
Step 1
See the "Displaying the Log File" section for more information.
Step 2
Step 3
copy debug-core time {ftp | scp | sftp} server full-file-name [login [password]]Table 11-26 provides the arguments and keywords for the copy debug-core command.
The following example shows how to extract debug information from November 9 at 06:45 a.m. of the current year to FTP server 10.0.0.191:
user@DETECTOR# copy debug-core 11090645 ftp 10.0.0.191 /home/debug/debug-file <user> <password>
