Detection: AWS Credential Access GetPasswordData

Updated Date: 2025-02-10 ID: 4d347c4a-306e-41db-8d10-b46baf71b3e2 Author: Bhavin Patel, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic identifies more than 10 GetPasswordData API calls within a 5-minute window in your AWS account. It leverages AWS CloudTrail logs to detect this activity by counting the distinct instance IDs accessed. This behavior is significant as it may indicate an attempt to retrieve encrypted administrator passwords for running Windows instances, which is a critical security concern. If confirmed malicious, attackers could gain unauthorized access to administrative credentials, potentially leading to full control over the affected instances and further compromise of the AWS environment.

1`cloudtrail` eventName=GetPasswordData eventSource = ec2.amazonaws.com 
2| bin _time span=5m 
3| rename user_name as user 
4| stats count min(_time) as firstTime max(_time) as lastTime dc(requestParameters.instanceId) as distinct_instance_ids by signature dest user user_agent src vendor_account vendor_region vendor_product 
5|  where distinct_instance_ids > 10 
6| `security_content_ctime(firstTime)` 
7| `security_content_ctime(lastTime)` 
8| `aws_credential_access_getpassworddata_filter`

Data Source

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

Macros Used

Name Value
cloudtrail sourcetype=aws:cloudtrail
aws_credential_access_getpassworddata_filter search *
aws_credential_access_getpassworddata_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
T1110.001 Password Guessing Credential Access
T1586.003 Cloud Accounts Resource Development
Exploitation
Weaponization
DE.AE
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 Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

You must install splunk AWS add on and Splunk App for AWS. This search works with AWS CloudTrail logs. We encourage the users to adjust the values of distinct_instance_ids and tweak the span value according to their environment.

Known False Positives

Administrator tooling or automated scripts may make these calls but it is highly unlikely to make several calls in a short period of time.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

User $user$ is seen to make mulitple GetPasswordData API calls to multiple instances from IP $src$

Risk Object Risk Object Type Risk Score Threat Objects
user user 49 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: 6