Syslog Filters

  • DeviceUser IdentificationUser MappingPalo Alto Networks User-ID Agent SetupSyslog Filters
The User-ID agent uses Syslog Parse profiles to filter syslog messages TechDocs_logo_cropped.png sent from the syslog senders that the agent monitors for IP address-to-username mapping information (see Configure Access to Monitored Servers). Each profile can parse syslog messages for either of the following event types, but not both:
  • Authentication (login) events—Used to add user mappings to the firewall.
  • Logout events—Used to delete user mappings that are no longer current. Deleting outdated mappings is useful in environments where IP address assignments change often.
Palo Alto Networks provides predefined Syslog Parse profiles through Applications content updates TechDocs_logo_cropped.png . To dynamically update the list of profiles as vendors develop new filters, schedule dynamic content updates (see Device > Dynamic Updates). The predefined profiles are global to the firewall, whereas the custom profiles you configure apply only to the virtual system (Location) selected under DeviceUser IdentificationUser Mapping.
Syslog messages must meet the following criteria for a User-ID agent to parse them:
  • Each message must be a single-line text string. A new line (\n) or a carriage return plus a new line (\r\n) are the delimiters for line breaks.
  • The maximum size for individual messages is 2,048 bytes.
  • Messages sent over UDP must be contained in a single packet; messages sent over SSL can span multiple packets. A single packet might contain multiple messages.
To configure a custom profile, click Add and specify the settings described in the following table. The field descriptions in this table use a login event example from a syslog message with the following format:
[Tue Jul 5 13:15:04 2005 CDT] Administrator authentication success User:domain\johndoe_4 Source:192.168.0.212
The complete procedure TechDocs_logo_cropped.png to configure the User-ID agent to parse a syslog sender for user mapping information requires additional tasks besides creating a Syslog Parse profile.
Field
Description
Syslog Parse Profile
Enter a name for the profile (up to 63 alphanumeric characters).
Description
Enter a description for the profile (up to 255 alphanumeric characters).
Type
Specify the type of parsing for filtering the user mapping information:
  • Regex Identifier—Use Event Regex, Username Regex, and Address Regex to specify regular expressions (regex) that describe search patterns for identifying and extracting user mapping information from syslog messages. The firewall uses the regex to match authentication or logout events in syslog messages and to match the usernames and IP addresses within matching messages.
  • Field Identifier—Use the Event String, Username Prefix, Username Delimiter, Address Prefix, and Address Delimiter fields to specify strings for matching the authentication or logout event and for identifying the user mapping information in syslog messages.
The remaining fields in the dialog vary based on your selection. Configure the fields as described in the following rows.
Event Regex
Enter the regex for identifying successful authentication or logout events. For the example message used with this table, the regex (authentication\ success) {1} extracts the first {1} instance of the string authentication success. The backslash before the space is a standard regex escape character that instructs the regex engine not to treat the space as a special character.
Username Regex
Enter the regex for identifying the username field in authentication success or logout messages. For the example message used with this table, the regex User:([a-zA-Z0-9\\\._]+) would match the string User:johndoe_4 and extract acme\johndoe1 as the username.
Address Regex
Enter the regex to identify the IP address portion of authentication success or logout messages. In the example message used with this table, the regular expression Source:([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}) matches the IPv4 address Source:192.168.0.212 and adds 192.168.0.212 as the IP address in the username mapping.
Event String
Enter a matching string to identify authentication success or logout messages. For the example message used with this table, you would enter the string authentication success.
Username Prefix
Enter the matching string to identify the beginning of the username field within authentication or logout syslog messages. The field does not support regex expressions such as \s (for a space) or \t (for a tab). In the example message used with this table, User: identifies the start of the username field.
Username Delimiter
Enter the delimiter that marks the end of the username field within an authentication or logout message. Use \s to indicate a standalone space (as in the example message) and \t to indicate a tab.
Address Prefix
Enter a matching string to identify the start of the IP address field in syslog messages. The field does not support regex expressions such as \s (for a space) or \t (for a tab). In the example message used with this table, Source: identifies the start of the address field.
Address Delimiter
Enter the matching string that marks the end of the IP address field within authentication success or logout messages. For example, enter \n to indicate the delimiter is a line break.

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