How IOCs are detected?

[paIoaItonetworks]

Hi,

I've recently noticed that an IOC that we created a month ago is still somehow being triggered, therefore an incident is generated. The IOC is a domain that we've found in a phishing email. I haven't visited the domain or clicked on that quarantined email, but somehow an incident occurred this morning. What actions could trigger an added IOC without directly accessing the IOC'ed website, file or IP? What could be the reason for this and what would be the solution to prevent it from happening again? Thanks in advance.

[nar]

Hello @paIoaItonetworks 
Thanks for reaching us using the Live Community.

If the indicator (Domain in this case) is seen and matched with EDR telemetry or XDR agent data and communication then an alert will be triggered.

Any established connections to that IP or domains will create an alert.

I understand you check the alert and found you haven’t visited the domain but I suggest investigating the event using XQL for more answers related to that event.

you may verify the event by running XQL query for “preset = network_story“ OR “dataset = xdr_data” dataset and then look for events related to that IOC Alert.

For domain IOCs the field its looking for is dst_action_external_hostname

Sample query: preset = network_story
| filter dst_action_external_hostname = “domain name”

For more help with XQL, please visit this article - https://docs-cortex.paloaltonetworks.com/r/Cortex-XDR/Cortex-XDR-XQL-Language-Reference/Get-Started-...

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