Manual Chapter : Enabling IP Address Intelligence

Applies To:

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BIG-IP DNS

  • 14.1.2, 14.1.0, 14.0.0

BIG-IP Analytics

  • 14.1.2, 14.1.0, 14.0.0

BIG-IP AFM

  • 14.1.2, 14.1.0, 14.0.0

BIG-IP PEM

  • 14.1.2, 14.1.0, 14.0.0

BIG-IP ASM

  • 14.1.2, 14.1.0, 14.0.0

BIG-IP AAM

  • 14.1.2, 14.1.0, 14.0.0

BIG-IP APM

  • 14.1.2, 14.1.0, 14.0.0

BIG-IP LTM

  • 14.1.2, 14.1.0, 14.0.0
Manual Chapter

Enabling IP Address Intelligence

Overview: Enabling IP address intelligence

An
IP intelligence database
is a list of IP addresses with questionable reputations. IP addresses gain a questionable reputation and are added to the database as a result of having performed exploits or attacks, or these addresses might represent proxy servers, scanners, or systems that have been infected. You can prevent system attacks by excluding traffic from malicious IP addresses. The IP Intelligence database is maintained online by a third party.
The BIG-IP® system can connect to an IP intelligence database, download the contents, and automatically keep the database up to date. You use iRules® to instruct the system on how to use IP address intelligence information. For example, iRules can instruct the system to verify the reputation of and log the originating IP address of all requests.
You can also use the IP address intelligence information within security policies in the Application Security Manager to log or block requests from IP addresses with questionable reputations.

Downloading the IP intelligence database

The requirements for using IP Intelligence are:
  • The system must have an IP Intelligence license.
  • The system must have an Internet connection either directly or through an HTTP proxy server (see proxy configuration values below).
  • The system must have DNS configured (go to
    System
    Configuration
    Device
    DNS
    ).
When an HTTP proxy server is configured, DNS configuration is not always required. However, in some cases, such as when the
proxy.host
is not defined as the IP address, DNS is required.
IP Intelligence is enabled by default if you have a license for it. You only need to enable it if it was previously disabled.
To enable IP Intelligence on the BIG-IP system, you enable auto-update to download the IP intelligence database to the system.
  1. Log in to the command line for the BIG-IP system.
  2. To determine whether IP intelligence auto-update is enabled, type the following command:
    tmsh list sys db iprep.autoupdate
    If the value of the
    iprep.autoupdate
    variable is
    disable
    , IP intelligence is not enabled. If it is
    enable
    , your task is complete. No further steps are necessary.
  3. If disabled, at the prompt, type
    tmsh modify sys db iprep.autoupdate value enable
    The system downloads the IP intelligence database and stores it in the binary file,
    /var/IpRep/F5IpRep.dat
    . It is updated every 5 minutes.
  4. If the BIG-IP system is behind a firewall, make sure that the BIG-IP system has external access to
    vector.brightcloud.com
    using port
    443
    .
    That is the IP Intelligence server from which the system gets IP Intelligence information.
  5. If the BIG-IP system connects to the Internet using a forward proxy server, set these system database variables.
    1. Type
      tmsh modify sys db proxy.host value
      hostname
      to specify the �
    2. Type
      tmsh modify sys db proxy.port value
      port_number
      to specify the port number of the proxy server.
    3. Type
      tmsh modify sys db proxy.username value
      username
      to specify the user name to log in to the proxy server.
    4. Type
      tmsh modify sys db proxy.password value
      password
      to specify the password to log in to the proxy server.
The IP Intelligence feature remains enabled unless you disable it with the command
tmsh modify sys db iprep.autoupdate value disable
.

Creating an iRule to log IP intelligence information

Before you can create an iRule to log IP Intelligence information, your system must have IP Intelligence enabled.
You use iRules to log IP Intelligence categories to the file
/var/log/ltm
. This is an example of the type of iRule you can write.
  1. On the Main tab, click
    Local Traffic
    iRules
    .
    The iRule List screen opens, displaying any existing iRules.
  2. Click
    Create
    .
    The New iRule screen opens.
  3. In the
    Name
    field, type a name, such as
    my_irule
    .
    The full path name of the iRule cannot exceed 255 characters.
  4. In the
    Definition
    field, type the iRule using Tool Command Language (Tcl) syntax.
    For example, to log all IP addresses and any associated IP Intelligence categories, type the following iRule:
    when CLIENT_ACCEPTED { log local0. "IP Intelligence for IP address [IP::client_addr]: [IP::reputation [IP::client_addr]]" }
    For complete and detailed information iRules syntax, see the F5 Networks DevCentral web site (
    http://devcentral.f5.com
    ).
  5. Click
    Finished
    .
    The new iRule appears in the list of iRules on the system.
When traffic is received from an IP address with a questionable reputation and that is included in the IP intelligence database, the system prints the IP Intelligence information in the
/var/log/ltm
log.
For complete and detailed information about iRules syntax, see the F5 Networks DevCentral web site,
http://devcentral.f5.com
.

Creating an iRule to reject requests with questionable IP addresses

Before you can create an iRule to reject requests based on an IP address reputation, your system must have IP Intelligence enabled.
You can use iRules to reject requests from IP addresses that have questionable reputations and are listed in the IP intelligence database. This is an example of the type of iRule you can write.
  1. On the Main tab, click
    Local Traffic
    iRules
    .
    The iRule List screen opens, displaying any existing iRules.
  2. Click
    Create
    .
    The New iRule screen opens.
  3. In the
    Name
    field, type a name, such as
    my_irule
    .
    The full path name of the iRule cannot exceed 255 characters.
  4. In the
    Definition
    field, type the iRule using Tool Command Language (Tcl) syntax.
    For example, to reject requests from IP addresses listed in the IP intelligence database because they could be Windows Exploits or Web Attacks, type the following iRule:
    when HTTP_REQUEST { set ip_reputation_categories [IP::reputation [IP::client_addr]] set is_reject 0 if {($ip_reputation_categories contains "Windows Exploits")} { set is_reject 1 } if {($ip_reputation_categories contains "Web Attacks")} { set is_reject 1 } if {($is_reject)} { log local0. "Attempted access from malicious IP address [IP::client_addr] ($ip_reputation_categories), request was rejected" HTTP::respond 200 content "<HTML><HEAD><TITLE>Rejected Request</TITLE> </HEAD><BODY>The request was rejected. <BR> Attempted access from malicious IP address</BODY></HTML>" } }
    For complete and detailed information about iRules syntax, see the F5 Networks DevCentral web site (
    http://devcentral.f5.com
    ).
  5. Click
    Finished
    .
    The new iRule appears in the list of iRules on the system.
When the system receives traffic from an IP address that is included in the IP intelligence database, the system prints the IP Intelligence information in the
/var/log/ltm
log.

Checking the reputation of an IP address

Before you can verify the reputation of an IP address, your system must have IP address intelligence enabled.
You can verify the reputation of a specific IP address.
  1. Log in to the command line for the BIG-IP system.
  2. At the prompt, type
    iprep_lookup
    IP_address
    where
    IP_address
    is the address whose reputation you want to verify. For example, to verify
    1.1.1.1
    :
    iprep_lookup 1.1.1.1 opening database in /var/IpRep/F5IpRep.dat size of IP reputation database = 41693298 iprep threats list for ip = 1.1.1.1 is: bit 4 - Scanners bit 5 - Denial of Service
    The system looks up the IP address, and if it is in the database, the command output displays the IP address intelligence categories that show the reason. In this case,
    1.1.1.1
    is a source of potential port or network scans and DoS attacks. If the IP address is not found in the IP intelligence database, the system returns the message
    iprep_lookup not found for ip =
    <ip_address>
    .

Checking the status of the IP intelligence database

You can display the status of the IP Intelligence database to learn when it was last updated and the number of questionable IP addresses it contains.
  1. Log in to the command line for the BIG-IP system.
  2. To display IP intelligence database status, type
    tmsh show sys iprep-status
    .
    The system displays the status. For example:
    ----------------------------------------------------------------------- Sys::IP Reputation Database Status ----------------------------------------------------------------------- Last time the server was contacted for updates 04/21/2012 09:33:31 Last time an update was received 04/21/2012 09:33:31 Total number of IP Addresses in the database 5516336 Number of IP Addresses received in the last update 136

IP intelligence categories

Along with the IP address, the IP intelligence database stores the category that explains the reason that the IP address is considered untrustworthy.
Category Name
Description
Spam Sources
IP addresses tunneling spam messages through proxy, anomalous SMTP activities and forum spam activities.
Windows Exploits
Active IP addresses that have exercised various exploits against Windows resources by offering or distributing malware, shell code, rootkits, worms, or viruses using browsers, programs, downloaded files, scripts, or operating system vulnerabilities.
Web Attacks
IP addresses involved in cross site scripting, iFrame injection, SQL injection, cross domain injection, or domain password brute force.
Botnets
IP addresses of computers that are infected with malicious software (Botnet Command and Control channels, and infected zombie machines) and are controlled as a group by a Bot master, and are now part of a botnet. Hackers can exploit botnets to send spam messages, launch various attacks, or cause target systems to behave in other unpredictable ways.
Scanners
IP addresses that are involved in reconnaissance, such as probes, host scan, domain scan, and password brute force, typically to identify vulnerabilities for later exploits.
Denial of Service
IP addresses involved in application DoS Attacks, or anomalous traffic detection.
Infected Sources
Active IP addresses that issue HTTP requests with a low reputation index score, or that are known malicious web sites offering or distributing malware, shell code, rootkits, worms, or viruses.
Phishing Proxies
IP addresses that host phishing sites, and other kinds of fraud activities, such as ad click fraud or gaming fraud.
Mobile Threats
IP addresses of malicious and unwanted mobile applications.
Tor Proxies
IP addresses acting as exit nodes for the Tor Network. Exit nodes are the last point along the proxy chain and make a direct connection to the originator’s intended destination.