Detection: AWS Exfiltration via Batch Service

Updated Date: 2024-11-14 ID: 04455dd3-ced7-480f-b8e6-5469b99e98e2 Author: Bhavin Patel, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies the creation of AWS Batch jobs that could potentially abuse the AWS Bucket Replication feature on S3 buckets. It leverages AWS CloudTrail logs to detect the JobCreated event, analyzing job details and their status. This activity is significant because attackers can exploit this feature to exfiltrate data by creating malicious batch jobs. If confirmed malicious, this could lead to unauthorized data transfer between S3 buckets, resulting in data breaches and loss of sensitive information.

1`cloudtrail` eventName = JobCreated 
2| fillnull 
3| rename user_name as user 
4| stats count min(_time) as firstTime max(_time) as lastTime by signature dest user user_agent src vendor_account vendor_region vendor_product 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7| `aws_exfiltration_via_batch_service_filter`

Data Source

Name Platform Sourcetype Source
AWS CloudTrail JobCreated AWS icon AWS 'aws:cloudtrail' 'aws_cloudtrail'

Macros Used

Name Value
cloudtrail sourcetype=aws:cloudtrail
aws_exfiltration_via_batch_service_filter search *
aws_exfiltration_via_batch_service_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1119 Automated Collection Collection
Exploitation
DE.CM
CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

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

Known False Positives

It is possible that an AWS Administrator or a user has legitimately created this job for some tasks.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

AWS Batch Job is created on account id - $vendor_account$ from src_ip $src$

Risk Object Risk Object Type Risk Score Threat Objects
user other 64 src

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset aws_cloudtrail aws:cloudtrail
Integration ✅ Passing Dataset aws_cloudtrail aws:cloudtrail

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: GitHub | Version: 5