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Description

This detection rule monitors for the creation of AWS Identity and Access Management (IAM) access keys. An IAM access key consists of an access key ID and secret access key, which are used to sign programmatic requests to AWS services. While IAM access keys can be legitimately used by developers and administrators for API access, their creation can also be indicative of malicious activity. Attackers who have gained unauthorized access to an AWS environment might create access keys as a means to establish persistence or to exfiltrate data through the APIs. Moreover, because access keys can be used to authenticate with AWS services without the need for further interaction, they can be particularly appealing for bad actors looking to operate under the radar. Consequently, it's important to vigilantly monitor and scrutinize access key creation events, especially if they are associated with unusual activity or are created by users who don't typically perform these actions. This hunting query identifies when a potentially compromised user creates a IAM access key for another user who may have higher privilleges, which can be a sign for privilege escalation. Hunting queries are designed to be executed manual during threat hunting.

  • Type: Hunting

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

  • Last Updated: 2022-03-03
  • Author: Bhavin Patel, Splunk
  • ID: 2a9b80d3-6340-4345-11ad-212bf3d0d111

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1136.003 Cloud Account Persistence
T1136 Create Account Persistence
Kill Chain Phase
  • Installation
NIST
  • DE.AE
CIS20
  • CIS 13
CVE 


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`cloudtrail` eventName = CreateAccessKey userAgent !=console.amazonaws.com errorCode = success 
| eval match=if(match(userIdentity.userName,requestParameters.userName),1,0) 
| search match=0 
| stats count min(_time) as firstTime max(_time) as lastTime by requestParameters.userName src eventName eventSource aws_account_id errorCode userAgent eventID awsRegion userIdentity.principalId user_arn 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
|`aws_createaccesskey_filter`

Macros

The SPL above uses the following Macros:

:information_source: aws_createaccesskey_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
  • userAgent
  • errorCode
  • requestParameters.userName

How To Implement

You must install splunk AWS add on and Splunk App for AWS. This search works with AWS CloudTrail logs.

Known False Positives

While this search has no known false positives, it is possible that an AWS admin has legitimately created keys for another user.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
63.0 70 90 User $user_arn$ is attempting to create access keys for $requestParameters.userName$ from this IP $src$

: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: 3