Cisco Service Control URL Blacklisting Solution Guide, Release 5.1.x
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Table of Contents
Cisco Service Control URL Blacklisting Solution Guide, Release 5.1.x
Managing URL Blacklists Using the Cisco Service Control Engine Platform
Configuring User Authorization How to Specify a New Owner for the sce-url-database
How to Configure Write Protection for the sce-url-database
How to Configure Lookup Protection for the sce-url-database
How to Configure the sce-url-database Encryption Key
How to Remove All the Protection Rules for the sce-url-database
How to View the Current sce-url-database Protection Settings
Guidelines for Managing the sce-url-database
The sce-url-database Import File
How to Import a sce-url-database File
How to Add an Entry to the sce-url-database
How to View the sce-url-database
How to Look for a Specific URL in the sce-url-database
How to Clear the sce-url-database
How to Enable Deep HTTP Inspection
How to Enable URL Normalization
How to Disable URL Normalization
How to Reset URL Normalization to the Default State
How to Display the Currently URL Normalization Configuration
Protected URL Database Configuration Example
Obtaining Documentation and Submitting a Service Request Cisco Service Control URL Blacklisting Solution Guide, Release 5.1.x
Managing URL Blacklists Using the Cisco Service Control Engine Platform
Configuring User Authorization
Protected URL Database Configuration Example
Obtaining Documentation and Submitting a Service Request
Managing URL Blacklists Using the Cisco Service Control Engine Platform
The Cisco Service Control Engine (Cisco SCE) platform-managed URL database resides on the Cisco SCE platform. The URL database, sce-url-database, is managed by using CLI commands rather than the Cisco Service Control Application for Broadband (Cisco SCA BB) Console. In addition to the advantage of having a separate URL database that is configurable directly by CLI commands, this database can be used to hide a list of URLs to prevent them from being accessed by the Console or the CLI.
The URL database must be declared as a separate flavor in the Cisco SCA BB application, but all the other configuration and management tasks are performed using the CLI.
The URL database can be protected. As part of protecting the sce-url-database, one user is designated as the owner of the database and only that user can execute the CLI commands on the database. Protection involves defining the authentication, authorization, and accounting (AAA) method (either based on local users or on a TACACS+ server, and so forth) and defining at least one user to be the owner of the database. For further details about the configuration, see the “Configuring the Management Interface and Security” chapter of the Cisco SCE 10000 Software Configuration Guide.
After the database is configured to be protected, no database information, (including information about the owner, database entries, authorization information, and the relevant saved configuration in the log files and in the relevant Cisco SCA BB reports, is accessible to any user. The database owner can change the authorizations by using the CLI. However, when any of the protection rules are relaxed (or all of the protection rules are relaxed by removing them) the database is reset automatically.
To protect the secrecy of the database information, the database entries can be imported to Cisco SCE (by using the CLI) in an encrypted form with the 128-bit key length Advanced Encryption Standard (AES). The key can be set or updated by using the appropriate CLI command; typically, this command should be run over a secure Telnet session.
There are two general categories of CLI commands related to the Cisco SCE-managed URL database:
Configuring User Authorization
The sce-url-database can be managed by a single authorized user, who is the designated owner of this database.
- If there is no designated owner, the sce-url-database is unprotected and the contents can be read and modified by any user.
- If there is a designated owner, the sce-url-database is protected. The default protection settings are as follows:
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Read permission—no-user. This setting is not configurable.
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User Authorization Guidelines
These are some of the guidelines for user authorization:
- The default user cannot be the owner.
- Only the owner can configure the protection settings. If there is no owner, the database is unprotected, and all the users have read and write permission. A user can be made the designated owner of the database only if the database does not have a designated owner.
- When a protection setting is relaxed, the database is reset automatically. Protection can be relaxed as follows:
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- The sce-url-database configuration information cannot be accessed from the running config and startup config file:
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How to Specify a New Owner for the sce-url-database
To specify a new owner for the sce-url-database, use the following command in the interface linecard configuration mode (config if):
sce-url-database protection owner (myself | (name user-name ))
The authorization level required by a user to perform this task is Admin.
If an owneris already assigned to the sce-url-database, that owner must first remove the owner designation using the no sce-url-database protection command, which removes all database protection (see the “How to Remove All the Protection Rules for the sce-url-database” section).
The following options are available to specify a new owner in the sce-url-database:
- myself —The owner of the database who is currently logged in. The user should not log in using the default username.
- user-name —The user that is to be designated as the owner of the database. The default username cannot be used. When specifying a user-name, if no such user exists (either in the local database or if in the TACACS+ server) or if the AAA authorization is not configured accordingly (that is, the logic user), there is no effective way of utilizing the permissions granted to this owner. Only after the relevant user or AAA settings are configured do the permissions of the owner user become effective.
The following are the results available after specifying a new owner in the sec-url-database:
- The specified user user-name is the owner of the sce-url-database.
- Read permission to the sce-url-database is not permitted for any user (including the owner).
- No Raw Data Records (RDRs) or traps contain data pertaining to the URLs in the sce-url-database.
- By default, only the owner has write permission to the sce-url-database.
- By default, none of the users, including the owner, can perform the lookup action..
How to Configure Write Protection for the sce-url-database
To configure write protection for the sce-url-database, use the following command in the interface linecard configuration mode (config if):
sce-url-database protection allow-write (all-users | owner-only)
This command can be executed only by the assigned owner of the sce-url-database. The authorization level required by a user to perform this task is Admin.
A person should already be assigned as the owner of the sce-url-database.
The following options are available to configure write protection in the sce-url-database:
The following are the default settings available while configuring write protection in the sce-url-database:
- If no owner is assigned, the default is all-users.
- If an owner is been assigned, the default is owner-only.
If protections are relaxed (changed from owner-only to all-users), the sce-url-database is reset automatically.
How to Configure Lookup Protection for the sce-url-database
To configure lookup-protection for the sce-url database, use the following command in the interface linecard configuration mode (config if):
sce-url-database protection allow-lookup (owner-only | no-user).
This command can be executed only by the assigned owner of the sce-url-database. The authorization level required by a user to perform this task is Admin.
An owner should already be assigned to the sce-url-database.
The following options are available to configure lookup protection in the sce-url-database:
The following are the default settings available while configuring lookup protection in the sce-url-database:
If protections are relaxed (changed from no-user to owner-only), the sce-url-database is reset automatically.
How to Configure the sce-url-database Encryption Key
To configure the sce-url-database encryption key, use the following command in the interface linecard configuration mode (config if):
sce-url-database protection encryption-key encryption-key
This command can be executed only by the assigned owner of the sce-url-database.The authorization level required by a user to perform this task is Admin.
An owner should already be assigned to the sce-url-database.
encryption-key —AES encryption key (128-bits long). The key is supplied in hexadecimal format and contains 32, 48, or 64 hexadecimal digits.
No encryption key is configured.
To remove the encryption key, use the no sce-url-database protection encryption-key command.
This command does not change any other sce-url-database protection settings.
Note
How to Remove All the Protection Rules for the sce-url-database
To remove all the protection rules for the sce-url-database, use the following command in the interface linecard configuration mode (config if):
no sce-url-database protection
This command can be executed only by the assigned owner of the sce-url-database.The authorization level required by a user to perform this task is Admin.
An owner should already be assigned to the sce-url-database.
The following are the results for removing all the protection rules in the sec-url-database:
How to View the Current sce-url-database Protection Settings
To view the current sce-url-database protection settings, use the use the following command in User EXEC (>) mode:
show interface linecard 0 sce-url-database protection.
The authorization level required by a user to perform this task is Viewer.
The following information is displayed when the show interface linecard 0 sce-url-database protection command is run:
Managing the sce-url-database
The designated owner of the sce-url-database can do perform the following tasks:
- Import the list of URLs from an sce-url-database file.
- Add a single entry to the sce-url-database.
- Clear the sce-url-database.
- Look up a specific URL (unless lookup protection is set to no-user).
If write protection is set to all-users, all the users can perform the following tasks:
- Import the list of URLs from an sce-url-database file.
- Add a single entry to the sce-url-database.
- Clear the sce-url-database.
If there is no designated owner (and therefore, no protection), all the users can view the entire sce-url-database.
If there is a designated owner, the contents of the sce-url-database are protected and cannot be displayed.
Guidelines for Managing the sce-url-database
The guidelines for managing the sce-url-database include:
- When a new file is imported, the existing database is cleared before the import. Because incremental update is not supported, the import file must contain all the relevant URLs, not just the new ones to be added to the database.
- Import operation ensures zero downtime for the protected URL blacklisting. The previous list of URLs remains in effect throughout the import operation. The new list of URLs comes into effect immediately after it is fully imported.
- A large number of new URLs can be added by importing an updated sce-url-database file. Typically, if the database is protected, this option is used with an encrypted file.
- New URLs can be added by using the sce-url-database add-entry command.
The sce-url-database Import File
The maximum number of entries permitted in an import file are:
The database import file either contains cleartext or is encrypted. If the file is encrypted, the matching encryption key must be configured by the database owner.
If the file is encrypted, it must be prefixed with a cleartext header. The encrypted file header must be as follows:
After the header, the following data appears in the encrypted format in the AES 128, CFB mode:
A random number (in the range [16…31]) of random bytes, followed by the word "Signed", and then again 32 random bytes.The import file format of the sce-url-database is:
- Flavor—Flavor ID. This must either be included for every line in the file or for none of the lines. The flavor must be separated from the URL by a <tab>.
- URL—(* | [*] [Host-Suffix] | [*] [Host-Suffix] / [URL-Prefix [*]] [URL suffix] [? Params-prefix])
Table 1 lists some URL examples.
How to Import a sce-url-database File
See the “The sce-url-database Import File” section for information about the sce-url-database import file format.
To import the sce-url-database files, use the following command in the interface linecard configuration mode (config if):
sce-url-database import cleartext-file | encrypted-file file-name flavor-id flavor-id
If the import file does not contain a flavor, specify the flavor in the CLI. The specified flavor must be the same as the one that was designated for the blacklist in the PQB file that was applied. Otherwise the import operation fails.
If the import file contains a flavor, do not specify the flavor in the CLI.
The authorization level required by a user to perform this task is Admin.
The user executing the command must have write permission to the sce-url-database.
The following options are available to import a sce-url-database file:
- cleartext-file
- encrypted-file —An encrypted file can be imported only if a matching encryption key has been configured.
- file-name —The Path and filename of the sce-url-database import file.
- flavor-id —The flavor that is applied to all the entries in the file.
The sce-url-database is empty.
The following are the results after importing a sce-url-database file:
- The sce-url-database is cleared.
- The entries from the file are written to the database.
- The duplicate keys in the file are overwritten with no warning.
- If failure occurs while an entry is being written, the writing continues with the subsequent entries.
The total number of failures and a listing of the failed file line numbers are reported after the import action is completed.
How to Add an Entry to the sce-url-database
To add an entry to the sce-url-database, use the following command in the interface linecard configuration mode (config if):
sce-url-database add-entry url-wildcard URL-wildcard-format flavor-id flavor-id
The authorization level required by a user to perform this task is Admin.
The user who is executing the command must have write permission to the sce-url-database.
The following options are available to add an entry to the sce-url database:
URL: (* | [*] [Host-Suffix] | [*] [Host-Suffix] / [URL-Prefix [*]] [URL suffix] [? Params-prefix])
See Table 1 for examples on how to define URLs.
How to View the sce-url-database
To view the sce-url-database, use the following command in the Privileged EXEC (#) mode:
show interface linecard 0 sce-url-database all-entries
The authorization level required by a user to perform this task is Admin.
All protection must be removed from the sce-url-database and there should be no assigned owner. If an assigned owner exists, the database becomes protected and cannot be displayed.
How to Look for a Specific URL in the sce-url-database
To look for a specific URL in the sce-url-database, use the following command in the Privileged EXEC (#) mode:
show interface linecard 0 sce-url-database url url
The authorization level required by a user to perform this task is Admin.
The user who is executing the command must have lookup permission in the sce-url-database.
url —Specific URL to look up in the sce-url-database.
The following are the results when the user tries to look for a specific URL in the sce-url-database file:
How to Clear the sce-url-database
To clear the sce-url-database, use the following command in the interface linecard configuration mode (config if):
The authorization level required by a user to perform this task is Admin.
The user executing the command must have write permission in the sce-url-database.
Enabling Deep HTTP Inspection
The HTTP flows may contain multiple transactions. Typically, each such inner URL should be verified against the protected URL database, not just the initial one. However, because this has a deep impact on performance HTTP inspection is disabled by default.
You can enable the deep HTTP inspection option from the Cisco SCA BB Console. The actual configuration relates to the number of HTTP transactions that are examined per HTTP flow (number of HTTP GET detections). By default, only the first transaction is examined; you can define this to be any number of transactions between 1 and 65535.
Note
How to Enable Deep HTTP Inspection
Step 1
Configuration > System Settings > Advanced Options tab > Advanced Service Configuration Options.
Figure 1 Advanced Service Configuration Options Window
Step 2
URL Normalization
URL normalization is a procedure that brings URL flavors having the same meaning into a canonical presentation, which minimizes the number of false-negative lookup results and may significantly improve the efficiency of the protected blacklisting operation.
URL normalization involves the following:
By default, these normalization operations are disabled, but when enabling URL normalization, both of them come into effect for the protected blacklist.
You must first enable URL normalization and then import the blacklist entries so that they are affected accordingly.
Configuring URL Normalization
Use the URL normalization commands to:
- Globally enable URL normalization.
- Globally disable URL normalization (default).
- Set URL normalization to the default state (disabled).
- Display the current configured state of URL normalization.
URL normalization should be configured before service configuration (PQB file) is applied to the Cisco SCE platform and before the sce-url-database is loaded.
How to Enable URL Normalization
To enable the URL normalization, use the following command in the interface linecard configuration mode (config if):
The authorization level required by a user to perform this task is Root.
How to Disable URL Normalization
To disable the URL normalization, use the following command in the interface linecard configuration mode (config if):
The authorization level required by a user to perform this task is Root.
How to Reset URL Normalization to the Default State
To reset the URL normalization to the default state, use the following command in the interface linecard configuration mode (config if):
By default, the URL normalization is disabled. The authorization level required by a user to perform this task is Root.
Protected URL Database Configuration Example
The following example shows how to configure the protected URL database, including defining the flavors in the Cisco SCA BB Console, configuring the protections in the Cisco SCE platform, and importing a URL file.
Step 1
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Figure 2 Flavor Settings—Flavors Editing Dialog Box
Step 3
Figure 3 Flavor Settings—Flavors Editing Dialog Box with Name and Index Information
Step 5
Step 6
Figure 4 Advanced Service Configuration Options Window
Step 7
Step 8
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Step 10
username BlacklistOwner privilege 10 password pass command as shown in the following example:Step 11
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Step 15
This should be done periodically over a secure Telnet session.
Step 16
This should be done periodically; either by copying the file to Cisco SCE first or by importing directly over FTP.Step 17
Step 18
Obtaining Documentation and Submitting a Service Request
For information on obtaining documentation, using the Cisco Bug Search Tool (BST), submitting a service request, and gathering additional information, see What’s New in Cisco Product Documentation at: http://www.cisco.com/c/en/us/td/docs/general/whatsnew/whatsnew.html.
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