Detection rules › Splunk

ASL AWS Create Policy Version to allow all resources

Status
production
Severity
medium
Group by
"actor.user.account.uid", "actor.user.uid", "api.operation", "api.request.data", "api.service.name", "cloud.provider", "cloud.region", "http_request.user_agent", "src_endpoint.ip"
Author
Patrick Bareiss, Splunk
Source
github.com/splunk/security_content

The following analytic identifies the creation of a new AWS IAM policy version that allows access to all resources. It detects this activity by analyzing AWS CloudTrail logs for the CreatePolicyVersion event with a policy document that grants broad permissions. This behavior is significant because it violates the principle of least privilege, potentially exposing the environment to misuse or abuse. If confirmed malicious, an attacker could gain extensive access to AWS resources, leading to unauthorized actions, data exfiltration, or further compromise of the AWS environment.

MITRE ATT&CK coverage

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

Rule body splunk

name: ASL AWS Create Policy Version to allow all resources
id: 22cc7a62-3884-48c4-82da-592b8199b72f
version: 9
creation_date: '2021-02-22'
modification_date: '2026-05-13'
author: Patrick Bareiss, Splunk
status: production
type: TTP
description: The following analytic identifies the creation of a new AWS IAM policy version that allows access to all resources. It detects this activity by analyzing AWS CloudTrail logs for the CreatePolicyVersion event with a policy document that grants broad permissions. This behavior is significant because it violates the principle of least privilege, potentially exposing the environment to misuse or abuse. If confirmed malicious, an attacker could gain extensive access to AWS resources, leading to unauthorized actions, data exfiltration, or further compromise of the AWS environment.
data_source:
    - ASL AWS CloudTrail
search: |-
    `amazon_security_lake` api.operation=CreatePolicy
      | spath input=api.request.data
      | spath input=policyDocument
      | regex Statement{}.Action="\*"
      | regex Statement{}.Resource="\*"
      | fillnull
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY actor.user.uid api.operation api.service.name
           http_request.user_agent src_endpoint.ip actor.user.account.uid
           cloud.provider cloud.region api.request.data
      | rename actor.user.uid as user api.operation as action api.service.name as dest http_request.user_agent as user_agent src_endpoint.ip as src actor.user.account.uid as vendor_account cloud.provider as vendor_product cloud.region as vendor_region
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `asl_aws_create_policy_version_to_allow_all_resources_filter`
how_to_implement: The detection is based on Amazon Security Lake events from Amazon Web Services (AWS), which is a centralized data lake that provides security-related data from AWS services. To use this detection, you must ingest CloudTrail logs from Amazon Security Lake into Splunk. To run this search, ensure that you ingest events using the latest version of Splunk Add-on for Amazon Web Services (https://splunkbase.splunk.com/app/1876) or the Federated Analytics App.
known_false_positives: While this search has no known false positives, it is possible that an AWS admin has legitimately created a policy to allow a user to access all resources. That said, AWS strongly advises against granting full control to all AWS resources and you must verify this activity.
references:
    - https://bishopfox.com/blog/privilege-escalation-in-aws
    - https://rhinosecuritylabs.com/aws/aws-privilege-escalation-methods-mitigation-part-2/
drilldown_searches:
    - name: View the detection results for - "$user$"
      search: '%original_detection_search% | search  user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: User $user$ created a policy version that allows them to access any resource in their account
    entity:
        field: user
        type: user
        score: 50
analytic_story:
    - AWS IAM Privilege Escalation
    - Scattered Lapsus$ Hunters
asset_type: AWS Account
mitre_attack_id:
    - T1078.004
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: cloud
security_domain: network
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1078/aws_create_policy_version/asl_ocsf_cloudtrail.json
          sourcetype: aws:asl
          source: aws_asl
      test_type: unit

Stages and Predicates

Stage 1: search

`amazon_security_lake` api.operation=CreatePolicy

Stage 2: spath

| spath input=api.request.data

Stage 3: spath

| spath input=policyDocument

Stage 4: regex

| regex Statement{}.Action="\*"

Stage 5: regex

| regex Statement{}.Resource="\*"

Stage 6: fillnull

| fillnull

Stage 7: stats

| stats count min(_time) as firstTime max(_time) as lastTime
    BY actor.user.uid api.operation api.service.name
       http_request.user_agent src_endpoint.ip actor.user.account.uid
       cloud.provider cloud.region api.request.data

Stage 8: rename

| rename actor.user.uid as user api.operation as action api.service.name as dest http_request.user_agent as user_agent src_endpoint.ip as src actor.user.account.uid as vendor_account cloud.provider as vendor_product cloud.region as vendor_region

Stage 9: search

| `security_content_ctime(firstTime)`

Stage 10: search

| `security_content_ctime(lastTime)`

Stage 11: search

| `asl_aws_create_policy_version_to_allow_all_resources_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Statement{}.Actionregex_match
  • "*"
Statement{}.Resourceregex_match
  • "*"
api.operationeq
  • CreatePolicy
sourcetypeeq
  • aws:asl