AWS Account Discovery By Rare User

[metadata]
creation_date = "2026/04/01"
integration = ["aws"]
maturity = "production"
updated_date = "2026/08/05"
min_stack_version = "9.3.0"
min_stack_comments = "Changing min stack to 9.3.0, the latest minimum supported version for 9.X releases."

[rule]
author = ["Elastic"]
description = """
Identifies the first time, within a lookback window, an identity performs AWS Organizations or IAM account enumeration
APIs. Attackers with compromised credentials often map the organization (accounts, OUs, roots, delegated admins) and
account-level metadata (aliases, summary) using the AWS CLI or SDKs. This is a New Terms rule detecting a rare
occurrence of the `cloud.account.id` and `user.name` pair for these actions.
"""
false_positives = [
    """
    Organization and security administrators, billing tooling, landing-zone automation, and delegated administrator
    workflows may call these APIs legitimately. Interactive or one-off use from unusual principals warrants review.
    """,
]
from = "now-6m"
index = ["logs-aws.cloudtrail-*"]
language = "kuery"
license = "Elastic License v2"
name = "AWS Account Discovery By Rare User"
note = """## Triage and analysis

### Investigating AWS Account Discovery By Rare User

AWS Organizations and IAM expose read APIs that reveal organization structure, member accounts, delegation, and
account-level aliases. Threat actors and tools such as Pacu (`organizations__enum`) chain these calls to understand
multi-account layout after credential access.

This rule uses [New Terms](https://www.elastic.co/guide/en/security/current/rules-ui-create.html#create-new-terms-rule) to detect when an identity makes a discovery API call that has not been seen in the configured history window.

### Possible investigation steps

**Identify the actor and session context**
- Confirm who `user.name` and `aws.cloudtrail.user_identity.arn` represent (human, workload role, automation).

**Analyze the source and origin**
- Review source.ip, geolocation, and whether the call aligns with normal egress for that principal.
- Inspect user_agent.original for CLI, Boto3/Botocore, consoles, or unfamiliar tooling.

**Correlate with additional events**
- Correlate with STS*(`GetCallerIdentity`, `AssumeRole`) and broader discovery or privilege changes in the same session.
- If the principal is new or rarely used, review IAM policies and recent key rotation.

### False positive analysis

- Documented org-admin or security roles in the management account; add exceptions by ARN if needed.
- Centralized compliance or CSPM that enumerates org structure on a schedule.

### Response and remediation

- If unexpected, rotate credentials for the implicated principal, review CloudTrail for follow-on API activity, and
  tighten least privilege on Organizations/IAM read APIs where appropriate.

### Additional information

- **[AWS IR Playbooks](https://github.com/aws-samples/aws-incident-response-playbooks)**
"""
references = [
    "https://kudelskisecurity.com/research/investigating-two-variants-of-the-trivy-supply-chain-compromise",
    "https://github.com/RhinoSecurityLabs/pacu/blob/master/pacu/modules/organizations__enum/main.py",
]
risk_score = 21
rule_id = "444c8fad-874f-4f59-b0ea-cf26cea478bd"
severity = "low"
tags = [
    "Domain: Cloud",
    "Domain: Identity",
    "Platform: AWS",
    "Data Source: AWS CloudTrail",
    "Service: AWS IAM",
    "Service: AWS Organizations",
    "Tactic: Discovery",
    "Rule Type: New Terms",
    "Resources: Investigation Guide",
]
timestamp_override = "event.ingested"
type = "new_terms"

query = '''
data_stream.dataset: "aws.cloudtrail"
    and event.outcome: "success"
    and source.ip:*
    and not aws.cloudtrail.session_credential_from_console: "true"
    and not aws.cloudtrail.user_identity.type: "AWSService"
    and (
        (
            event.provider: "organizations.amazonaws.com"
            and event.action: (
                "DescribeOrganization" or "DescribeOrgnanizationalUnit" or "ListAccounts" or "ListRoots"
                or "ListOrganizationalUnitsForParent" or "ListAccountsForParent" or "ListPolicies"
                or "ListAWSServiceAccessForOrganization" or "ListDelegatedAdministrators"
                or "ListDelegatedServicesForAccount" or "DescribeResourcePolicy"
            )
        )
        or (
            event.provider: "iam.amazonaws.com"
            and event.action: ("ListAccountAliases" or "GetAccountSummary")
        )
    )
    and not user_agent.original: (*Terraform*)
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1087"
name = "Account Discovery"
reference = "https://attack.mitre.org/techniques/T1087/"
[[rule.threat.technique.subtechnique]]
id = "T1087.004"
name = "Cloud Account"
reference = "https://attack.mitre.org/techniques/T1087/004/"


[[rule.threat.technique]]
id = "T1580"
name = "Cloud Infrastructure Discovery"
reference = "https://attack.mitre.org/techniques/T1580/"


[rule.threat.tactic]
id = "TA0007"
name = "Discovery"
reference = "https://attack.mitre.org/tactics/TA0007/"

[rule.investigation_fields]
field_names = [
    "@timestamp",
    "user.name",
    "user_agent.original",
    "source.ip",
    "aws.cloudtrail.user_identity.arn",
    "aws.cloudtrail.user_identity.type",
    "aws.cloudtrail.user_identity.access_key_id",
    "event.action",
    "event.outcome",
    "event.provider",
    "cloud.account.id",
    "cloud.region",
]

[rule.new_terms]
field = "new_terms_fields"
value = ["cloud.account.id", "user.name"]
[[rule.new_terms.history_window_start]]
field = "history_window_start"
value = "now-10d"