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Description

This search provides detection of users with KMS keys performing encryption specifically against S3 buckets.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2021-01-11
  • Author: Rod Soto, Patrick Bareiss Splunk
  • ID: 884a5f59-eec7-4f4a-948b-dbde18225fdc

Annotations

ATT&CK
ID Technique Tactic
T1486 Data Encrypted for Impact Impact
Kill Chain Phase
  • Exploitation
NIST
CIS20
CVE
1
2
3
4
5
6
`cloudtrail` eventName=CopyObject requestParameters.x-amz-server-side-encryption="aws:kms" 
| rename requestParameters.bucketName AS bucket_name, requestParameters.x-amz-copy-source AS src_file, requestParameters.key AS dest_file 
| stats count min(_time) as firstTime max(_time) as lastTime values(src_file) AS src_file values(dest_file) AS dest_file values(userAgent) AS userAgent values(region) AS region values(src) AS src by user 
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` 
|`aws_detect_users_with_kms_keys_performing_encryption_s3_filter`

Macros

The SPL above uses the following Macros:

Note that aws_detect_users_with_kms_keys_performing_encryption_s3_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

  • _time
  • eventName
  • requestParameters.x-amz-server-side-encryption
  • requestParameters.bucketName
  • requestParameters.x-amz-copy-source
  • requestParameters.key
  • userAgent
  • region

How To Implement

You must install splunk AWS add on and Splunk App for AWS. This search works with AWS CloudTrail logs

Known False Positives

bucket with S3 encryption

Associated Analytic story

RBA

Risk Score Impact Confidence Message
15.0 30 50 User $user$ with KMS keys is performing encryption, against S3 buckets on these files $dest_file$

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 1