Detection: AWS Exfiltration via DataSync Task

Updated Date: 2024-09-30 ID: 05c4b09f-ea28-4c7c-a7aa-a246f665c8a2 Author: Bhavin Patel, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the creation of an AWS DataSync task, which could indicate potential data exfiltration. It leverages AWS CloudTrail logs to identify the CreateTask event from the DataSync service. This activity is significant because attackers can misuse DataSync to transfer sensitive data from a private AWS location to a public one, leading to data compromise. If confirmed malicious, this could result in unauthorized access to sensitive information, causing severe data breaches and compliance violations.

1`cloudtrail` eventName = CreateTask eventSource="datasync.amazonaws.com" 
2| rename  requestParameters.*  as *  
3| stats count min(_time) as firstTime max(_time) as lastTime by src_ip aws_account_id awsRegion eventName destinationLocationArn sourceLocationArn userAgent user_arn userIdentity.principalId  errorCode 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `aws_exfiltration_via_datasync_task_filter`

Data Source

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

Macros Used

Name Value
cloudtrail sourcetype=aws:cloudtrail
aws_exfiltration_via_datasync_task_filter search *
aws_exfiltration_via_datasync_task_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
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
APT1
APT28
Agrius
Chimera
Confucius
Ember Bear
FIN5
FIN6
Gamaredon Group
Ke3chang
Mustang Panda
OilRig
Patchwork
RedCurl
Sidewinder
Threat Group-3390
Tropic Trooper
Winter Vivern
menuPass

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 has legitimately created this task for creating backup. Please check the sourceLocationArn and destinationLocationArn of this task

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
DataSync task created on account id - $aws_account_id$ by user $user_arn$ from src_ip $src_ip$ 64 80 80
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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: 3