Azure Sentinel Linux Syslog agent configuration

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New Contributor

Hello All,

 

I looking for help with trying to ingest Cisco NGFWv syslog messages in Azure Sentinel. I've configured my Linux Syslog agent to collect my Common Event Format (CEF) Syslog messages and forward them to Azure Sentinel but, I've been unsuccessful.

 

My Linux syslog agent is receiving syslog messages from my Cisco NGFWv but, isn't forwarding them to Azure Sentinel, even thought my Linux syslog agent is connected (sending heartbeast) to Azure Sentinel.

 

Below is a message I'm seeing when executing the troubleshooting command provide by Azure Sentinel within their configuration instructions:

----------------------------------------------------

Could not locate "CEF" message in tcpdump
Fetching CEF messages from daemon files.
Taking 2 snapshots in 5 seconds diff and compering the amount of CEF messages.
If found increasing CEF messages daemon is receiving CEF messages.
Validating the CEF\ASA logs are received and are in the correct format when received by syslog daemon
sudo tac /var/log/syslog
Located 0
CEF\ASA messages
Validating the CEF\ASA logs are received and are in the correct format when received by syslog daemon
sudo tac /var/log/syslog
Located 0
CEF\ASA messages
Error: no CEF messages received by the daemon.
Please validate that you do send CEF messages to agent.
Checking daemon incoming connection for tcp and udp
This will take 60 seconds.
sudo tcpdump -A -ni any port 25226 -vv
tcpdump: listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes
Could not locate "CEF" message in tcpdump
Simulating mock data which you can find in your workspace
This will take 60 seconds.
sudo tcpdump -A -ni any port 25226 -vv
tcpdump: listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes
15:38:46.098278 IP (tos 0x0, ttl 64, id 64704, offset 0, flags [DF], proto TCP (6), length 411)
127.0.0.1.55128 > 127.0.0.1.25226: Flags [P.], cksum 0xff8f (incorrect -> 0x133c), seq 2265321169:2265321528, ack 497104721, win 512, options [nop,nop,TS val 942763643 ecr 942763050], length 359
E.....@.@.>..........Xb.......7Q...........
Mock messages sent and received in daemon incoming port [514] and to the omsagent port [25226].
Notice: To tcp dump manually execute the following command - 'tcpdump -A -ni any port 25226 -vv'
[u'syslog 3437 1 0 15:36 ? 00:00:00 /usr/sbin/rsyslogd -n']
Found rsyslogd process running on this machine.
[]
Warning: please make sure your logging daemon configuration does not store unnecessary logs. This may cause a full disk on your machine, which will disrupt the function of the oms agent installed. For more information:
https://www.rsyslog.com/doc/master/configuration/actions.html
Completed troubleshooting.
Please check Log Analytics to see if your logs are arriving. All events streamed from these appliances appear in raw form in Log Analytics under CommonSecurityLog type
Notice: If no logs appear in workspace try looking at omsagent logs:
tail -f /var/opt/microsoft/omsagent/****/log/omsagent.log
Warning: Make sure that the logs you send comply with RFC 5424.

----------------------------------------------------------------------------

 

Thanks in advance!

 

2 Replies

Hi @Will_Network,

I'm not sure if this is related to Sentinel or to the LA agent.

On the LA agent side, I'll refer this thread to the relevant PMs.

To cover the Sentinel side as well, plesae post this message on the Azure Sentinel community forum.

 

Thank you

@Will_Network 

It seems like your machine does not get CEF messages:

  • "Could not locate "CEF" message in tcpdump"
  • "Error: no CEF messages received by the daemon."

Can you please make sure that Cisco NGFWv can send CEF formatted messages? In case it's not supported I suggest sending the events to the Syslog table (instead of CommonSecurtyLog).