Alert Field Overrides

Overrides provide flexible, programmatically customizable alerts that allow users to tailor and fine-tune alerts.

Field Overrides

In addition to the rule, title, and dedup functions, Rules can also contain the following functions to control the routing and alerting of detections.

Similarly, these functions take an argument of the currently processed event.

Any optional functions listed below left undefined will default to the rule metadata.

Referencing destinations was made available in v1.16 and newer versions.

Finding Destination UUID



Expected Return



Generates a tailored severity in the alert Used to contextualize the detection to (de)escalate severity

Note that severity affects alert routing

String (ENUM)




Generates a tailored description in the alert




Generates a tailored reference in the alert




Generates a tailored runbook in the alert




Used to override all other fields used for alert routing. Empty lists are used for alert suppression.

List [String]

Destination Name

["Main Slack"]

Finding Destination UUID

Versions prior to v1.16 require destinations to return the destinations To get the UUID of a detection:

  • Navigate to Settings > Destinations

  • Click on the name of the target destination

  • Extract the UUID from the current page URL

e.g. https[:]// Result UUID: 01234567-1edf-4edb-8f5b-0123456789a

For example, the functions below can be used to fine-tune a detection:

HIGH_PRIORITY_REGIONS = ['us-east-1', 'eu-west-1']
# This rule applies to S3 Server Access Logs
def rule(event):
if event.get('bucket') not in {'my-set-of-authenticated-buckets'}:
return False
return 'requester' not in event
# This rule groups alert events by the bucket name
def dedup(event):
return event.get('bucket')
# Alerts will have a title like `Unauthenticated Access to S3 Bucket my-super-secret-data`
def title(event):
return 'Unauthenticated Access to S3 Bucket {}'.format(event.get('bucket'))
# Alert context will contain the bucket name and the requester information
def alert_context(event):
return {'bucket': event.get('bucket'), 'requester': event.get('requester')}
# Alert Overrides
# Generated alerts will be Critical if it is in a high priority region, Info otherwise
def severity(event):
if event['awsRegion'] in HIGH_PRIORITY_REGIONS:
return 'Critical'
return 'Low'
# Rules with this function defined will have generated descriptions, useful for providing more details to an Alert
def description(event):
return 'Unauthenticated Access to S3 Bucket {} made by {}'.format(event.get('bucket'), event.get('requester'))
# Reference can be used to link to relevant external links
def reference(event):
return ''
# Runbook can be used to inform how an analyst should respond to an Alert
def runbook(event):
return 'Investigate the requester information as well as the S3 Bucket permissions.'
# Destinations is functionally a dynamic destination override, useful for controlling the reporting of generated alerts
def destinations(event):
if event['awsRegion'] in HIGH_PRIORITY_REGIONS:
return ['01234567-1edf-4edb-8f5b-0123456789a']
# Suppress the alert
return []

Routing Order of Precedence

Alert routing is based on the following order of precedence (from lowest precedence to highest):

  1. Static Severity - Default alert routing based on the severity metadata field set for the detection.

  2. Generated Severity - Destinations associated with returned severity function defined in the Python body.

  3. Static Destinations - Destinations based on the Destination Override metadata field set for the detection.

  4. Generated Destinations - Destinations returned by the destinations function defined in the Python body.