syslog

ResultIt’s a bit of an odd situation but sometimes you might want to take information from a cloud service in this case Cortex XDR from Palo Alto Networks and drag it into an on premise logging service. This guide will have a look at how to get this log data in as well as parse it such that you can break out the individual fields in the log entry.

In looking at the documentation it appears that the logs are in the Comment Event Format (CEF) but are then wrapped up in syslog for transmission. Although Graylog can absorb CEF directly this additional layer of syslog means we have to take in the syslog and then send the event messages through a processing pipeline in Graylog to extract the CEF data.

So onto the guide – which assume you are familiar with the operation of the Cortex XDR management console and Graylog (shown version is 3.3), for simplicity the code snippet you’ll need is also shown below from GitHub.

Code snippet from the screenshot sequence:

If you are running an HPE Aruba (formally ProCurve) switch you may come across cases where your switch (in the example above a 5400R zl2) has multiple IP Addresses/VLANs and you need it to talk to another service (in my case syslog and sFlow receivers) on a set interface.

When this occurs you can use the ip source-interface command (make sure you are in config mode first) to define the IP Address or VLAN that you want the switch to talk out on. In my case VLAN2 which is used as the management network for the network switches (VLAN1 being the default network that switches use if multiple addresses are configured).