Detection: AWS Credential Access GetPasswordData

Updated Date: 2024-05-21 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.

Search

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	Supported App
AWS CloudTrail GetPasswordData	AWS	`'aws:cloudtrail'`	`'aws_cloudtrail'`	N/A

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

DarkVishnya

Dragonfly

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

AWS Identity and Access Management Account Takeover

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: 2