panos-parser(): parsing PAN-OS log messages

1: Message format parsed by panos-parser()

2: PAN-OS parser options

The PAN-OS (a short version of Palo Alto Networks Operating System) parser can parse log messages originating from Palo Alto Networks devices. Even though these messages completely comply to the RFC standards, their MESSAGE part is not a plain text. Instead, the MESSAGE part contains a data structure that requires additional parsing.

The panos-parser() of AxoSyslog solves this problem, and can separate PAN-OS log messages to name-value pairs. For details on using value-pairs in AxoSyslog, see Structuring macros, metadata, and other value-pairs.

Prerequisites

Version 3.29 of AxoSyslog or later.
Install the axosyslog-scl package on Debian/Ubuntu. On RHEL and compatible distributions, the SCL files are part of the axosyslog base package.

Your configuration must also contain @include "scl.conf", which the default configuration file already does. If the SCL files are missing, AxoSyslog fails to start with an unexpected LL_IDENTIFIER error.
Terminal window
```
@include "scl.conf"
```
The panos-parser() driver is a reusable configuration snippet (SCL). For details on using or writing such configuration snippets, see Reusing configuration blocks. You can find its source in scl/paloalto/panos.conf on GitHub.
PAN-OS log messages from Palo Alto Networks devices.

Limitations

The panos-parser() only works on AxoSyslog version 3.29 or later.

Configuration

You can include the panos-parser() in your AxoSyslog configuration like this:

   parser p_parser{
        panos-parser();
    };

1 - Message format parsed by panos-parser()

This section illustrates the most commonly used PAN-OS log format on the AxoSyslog side.

For information about customizing log format on the PAN-OS side, see the relevant section of the PAN-OS^® Administrator’s Guide.

Message format and log format

Using the panos-parser(), the parsed messages in AxoSyslog have the following general format:

   <PRI><TIMESTAMP> <HOST> <PALO-ALTO-fields-in-CSV-format>

There are several “types” of log formats in Palo Alto Networks PAN-OS. For example, the most commonly used SYSTEM type has the following message format on the AxoSyslog side after parsing:

   <12>Apr 14 16:48:54 paloalto.test.net 1,2020/04/14 16:48:54,unknown,SYSTEM,auth,0,2020/04/14 16:48:54,,auth-fail,,0,0,general,medium,failed authentication for user 'admin'. Reason: Invalid username/password. From: 10.0.10.55.,1718,0x0,0,0,0,0,,paloalto

2 - PAN-OS parser options

The panos-parser() has the following options:

prefix()


Synopsis:	prefix()
Default:	“.panos.”

Description: Insert a prefix before the name part of the parsed name-value pairs to help further processing. For example:

To insert the my-parsed-data. prefix, use the prefix(my-parsed-data.) option.
To refer to a particular data that has a prefix, use the prefix in the name of the macro, for example, ${my-parsed-data.name}.
If you forward the parsed messages using the IETF-syslog protocol, you can insert all the parsed data into the SDATA part of the message using the prefix(.SDATA.my-parsed-data.) option.

Names starting with a dot (for example, .example) are reserved for use by AxoSyslog. If you use such a macro name as the name of a parsed value, it will attempt to replace the original value of the macro (note that only soft macros can be overwritten, see Hard versus soft macros for details). To avoid such problems, use a prefix when naming the parsed values, for example, prefix(my-parsed-data.)