ID | Technique | Tactic |
---|---|---|
T1078.004 | Cloud Accounts | Defense Evasion |
T1078 | Valid Accounts | Initial Access |
Detection: AWS SetDefaultPolicyVersion
Description
The following analytic detects when a user sets a default policy version in AWS. It leverages AWS CloudTrail logs to identify the SetDefaultPolicyVersion
event from the IAM service. This activity is significant because attackers may exploit this technique for privilege escalation, especially if previous policy versions grant more extensive permissions than the current one. If confirmed malicious, this could allow an attacker to gain elevated access to AWS resources, potentially leading to unauthorized actions and data breaches.
Search
1`cloudtrail` eventName=SetDefaultPolicyVersion eventSource = iam.amazonaws.com
2| stats count min(_time) as firstTime max(_time) as lastTime values(requestParameters.policyArn) as policy_arn by src requestParameters.versionId eventName eventSource aws_account_id errorCode userAgent eventID awsRegion userIdentity.principalId user_arn
3| `security_content_ctime(firstTime)`
4| `security_content_ctime(lastTime)`
5| `aws_setdefaultpolicyversion_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
AWS CloudTrail SetDefaultPolicyVersion | AWS | 'aws:cloudtrail' |
'aws_cloudtrail' |
N/A |
Macros Used
Name | Value |
---|---|
cloudtrail | sourcetype=aws:cloudtrail |
aws_setdefaultpolicyversion_filter | search * |
aws_setdefaultpolicyversion_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
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 set a default policy to allow a user to access all resources. That said, AWS strongly advises against granting full control to all AWS resources
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
From IP address $src$, user $user_arn$ has trigged an event $eventName$ for updating the the default policy version | 30 | 50 | 60 |
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