S3 Object Exfiltration from Anonymous User

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Id	15d3bf4e-8708-41c8-a836-8b0aa5be730e
Rulename	S3 Object Exfiltration from Anonymous User
Description	Identify attempted exfiltration of S3 Bucket objects by an anonymous User
Severity	Medium
Tactics	Collection
Techniques	T1530
Required data connectors	AWS
Kind	Scheduled
Query frequency	5m
Query period	5m
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_S3ObjectExfiltrationByAnonymousUser.yaml
Version	1.0.0
Arm template	15d3bf4e-8708-41c8-a836-8b0aa5be730e.json

KQL

AWSCloudTrail
| where ((UserIdentityAccountId =~ @'ANONYMOUS_PRINCIPAL' or UserIdentityPrincipalid == "Anonymous") and EventName == 'GetObject')
| extend
   BucketName = parse_json(RequestParameters).bucketName,
   ObjectKey = parse_json(RequestParameters).key
| extend UserName = substring(UserIdentityPrincipalid, indexof_regex(UserIdentityPrincipalid, ":") + 1)
| extend Name = split(UserName,'@')[0],UpnSuffix = split(UserName,'@')[1]

YAML

triggerThreshold: 0
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: Name
    columnName: Name
  - identifier: UPNSuffix
    columnName: UpnSuffix
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SourceIpAddress
requiredDataConnectors:
- dataTypes:
  - AWSCloudTrail
  connectorId: AWS
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_S3ObjectExfiltrationByAnonymousUser.yaml
name: S3 Object Exfiltration from Anonymous User
relevantTechniques:
- T1530
status: Available
version: 1.0.0
queryPeriod: 5m
kind: Scheduled
id: 15d3bf4e-8708-41c8-a836-8b0aa5be730e
query: |
  AWSCloudTrail
  | where ((UserIdentityAccountId =~ @'ANONYMOUS_PRINCIPAL' or UserIdentityPrincipalid == "Anonymous") and EventName == 'GetObject')
  | extend
     BucketName = parse_json(RequestParameters).bucketName,
     ObjectKey = parse_json(RequestParameters).key
  | extend UserName = substring(UserIdentityPrincipalid, indexof_regex(UserIdentityPrincipalid, ":") + 1)
  | extend Name = split(UserName,'@')[0],UpnSuffix = split(UserName,'@')[1]  
description: |
    'Identify attempted exfiltration of S3 Bucket objects by an anonymous User'
queryFrequency: 5m
severity: Medium
triggerOperator: gt
tactics:
- Collection

ARM