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Receiving CEE enhanced syslog in rsyslog

We want to receive syslog messages from another system that contain Windows Events. The messages are sent in the CEE enhanced format. The syslog messages should be stored in a database to be reviewed with Adiscon LogAnalyzer.

Things to think about

For the basics, we need at least a listener for UDP or TCP, depending on what you are using. We will configure both for now. As additional modules, we will need mmjsonparse, which has been introduced in v6. And in addition the output module for a MySQL database.

To enable the modules, we need some templates.

Note, that the receiver ports you specify must match the ports on the sending machines.

Config Statements

# modules
$ModLoad imuxsock # provides support for local system logging
$ModLoad imklog   # provides kernel logging support (previously done by rklogd)
$ModLoad immark  # provides --MARK-- message capability
$ModLoad mmjsonparse
$ModLoad ommysql
$ModLoad imudp
$ModLoad imtcp
# provides UDP syslog reception
$UDPServerRun 514
# provides TCP syslog reception
$InputTCPServerRun 10514
# templates
$template database,"insert into systemevents (DeviceReportedTime, FromHost, EventLogType, EventSource, EventID, 
EventCategory, EventUser, Facility, Priority, Message) values ('%timereported:::date-rfc3339%', '%$!source%', 
'%$!nteventlogtype%', '%$!sourceproc%', '%$!id%', '%$!categoryid%', '%$!user%', '%syslogfacility%', 
'%syslogpriority%', '%$!msg:::space-cc%')",SQL
# actions
*.* :mmjsonparse:
& :ommysql:mysqlserver,database,user,password;database

How it works

First of all, we have the modules being loaded. In addition to the modules needed for local logging, we have loaded the input modules for UDP and TCP syslog.

The next part will enable the listeners. For UDP we use the default port 514. For TCP we use port 10514. Please note, that the senders MUST match the respective port.

The third step is to create a template. You can see it at as 4 lines here, but it really is a single line. mmjsonparse will take messages and process them. It will automatically detect the CEE enhanced json format an create custom properties with the name fields in the message and fill it the available content. But, to use it for a database insert, we need a custom insert statement. As you can see, the most important fields are present. These fields should already be available in the database that is used by Adiscon LogAnalyzer. We now only need to tell rsyslog, which database field will be filled with which field from the json message.

The format differences are important. Some fields will be filled with information from the syslog header, like the timestamp, facility and priority. Thus we can use the regular properties. The properties from the json message always need to start with "$!". And for the msg property, we will additionaly use the space-cc option. This will strip line feeds from multiline messages.

Finally we have the actions. The first action "*.* :mmjsonparse:" will be applied to all messages here, though it will not be able to parse messages from the local log socket. This calls the mmjsonparse module to parse the message and fill the fields as mentioned before. The second line holds the output to mysql. We extended the chain of actions by "&" instead of a filter.

Important notes

The most crucial part is the template. If the template is not correct, the whole action chain will not work. Or it will work at least not correctly. Though, the above template should work fine with most Windows Events, it might be necessary to alter the template for other message types and database structures.

2 thoughts on “Receiving CEE enhanced syslog in rsyslog

  1. Pingback: Structured Logging with Rsyslog and Elasticsearch | Sematext Blog

  2. Pingback: Parsing JSON (CEE) Logs and Sending them to Elasticsearch rsyslog

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