Netflow from untangle has epoc issue with timestamp (1970 date in timestamp)

[gauthig]

Looks like similar problem that Fortinet filebeat module had (Timezone parsing error in pipeline of Fortinet module #19010)

Using standard netflow filebeat module and untagle firewall with Netflow V9 format the timestamp in the index looks like:
"timestamp":"1970-01-01T02:50:49.000Z"

Several fields convert correctly several do not:

Working
event.created | Apr 10, 2021 @ 11:30:01.120
event.ingested | Apr 10, 2021 @ 11:30:02.533

Not working
netflow.exporter.timestamp | Dec 31, 1969 @ 20:26:19.000
event.start | Dec 31, 1969 @ 20:20:51.697
event.end | Dec 31, 1969 @ 20:21:16.792

ELK stack Version: 7.12.0
Ubuntu 20.04.2 LTS
Untangle 16

[elasticmachine]

Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

[botelastic]

This issue doesn't have a Team:<team> label.

[marc-gr]

Hello! Do you have some example of the raw logs that are not parsed correctly?

[botelastic]

Hi!
We just realized that we haven't looked into this issue in a while. We're sorry!

We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1.
Thank you for your contribution!

[elasticmachine]

Pinging @elastic/sec-deployment-and-devices (Team:Security-Deployment and Devices)