Try in Splunk Security Cloud

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.

  • Type: Anomaly

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-21
  • Author: Bhavin Patel, Splunk
  • ID: 4d347c4a-306e-41db-8d10-b46baf71b3e2

Annotations

ATT&CK

ATT&CK

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
Kill Chain Phase
  • Weaponization
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


1
2
3
4
5



`cloudtrail` eventName=GetPasswordData eventSource = ec2.amazonaws.com 
|  bin _time span=5m 
|  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 
|  where distinct_instance_ids > 10 
| `aws_credential_access_getpassworddata_filter`

Macros

The SPL above uses the following Macros:

:information_source: aws_credential_access_getpassworddata_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • eventName
  • eventSource
  • userIdentity.userName
  • userAgent
  • userIdentity.accountId
  • sourceIPAddress
  • awsRegion

How To Implement

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

RBA

Risk Score Impact Confidence Message
49.0 70 70 User $user_arn$ is seen to make mulitple GetPasswordData API calls to instance ids $instance_ids$ from IP $src_ip$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

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 | version: 2