Detection: AWS Credential Access GetPasswordData

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|  stats count values(errorCode) as errorCode dc(requestParameters.instanceId) as distinct_instance_ids values(requestParameters.instanceId) as instance_ids by aws_account_id src_ip user_arn userAgent eventName _time 
4|  where distinct_instance_ids > 10 
5| `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
T1586 Compromise Accounts Resource Development
T1586.003 Cloud Accounts Resource Development
T1110 Brute Force Credential Access
T1110.001 Password Guessing Credential Access
KillChainPhase.EXPLOITAITON
KillChainPhase.WEAPONIZATION
NistCategory.DE_AE
Cis18Value.CIS_10
APT29
APT28
APT38
APT39
APT41
Agrius
DarkVishnya
Dragonfly
Ember Bear
FIN5
Fox Kitten
HEXANE
OilRig
Turla
APT28
APT29

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 Risk Score Impact Confidence
User $user_arn$ is seen to make mulitple GetPasswordData API calls to instance ids $instance_ids$ from IP $src_ip$ 49 70 70
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