AWS CloudTrail Account Discovery

Severity: informational
Entities: aws_account_ids, aws_arns, ip_addresses, trace_ids, usernames
Log types: AWS.CloudTrail
Reference: https://attack.mitre.org/techniques/T1087/
Source: github.com/panther-labs/panther-analysis

Adversaries may attempt to get a listing of accounts on a system or within an environment. This information can help adversaries determine which accounts exist to aid in follow-on behavior.

MITRE ATT&CK coverage

Tactic	Techniques
Discovery	`T1087` Account Discovery

Rule body yaml

AnalysisType: rule
Description: Adversaries may attempt to get a listing of accounts on a system or within an environment. This information can help adversaries determine which accounts exist to aid in follow-on behavior.
DisplayName: "AWS CloudTrail Account Discovery"
Enabled: true
Filename: aws_cloudtrail_account_discovery.py
Reference: https://attack.mitre.org/techniques/T1087/
Reports:
  MITRE ATT&CK:
    - TA0007:T1087
Severity: Info
CreateAlert: false
Tests:
  - ExpectedResult: true
    Log:
      awsRegion: us-east-1
      eventCategory: Management
      eventID: 0b51d284-19f7-42cf-a103-276602aeada5
      eventName: DescribeAccount
      eventSource: organizations.amazonaws.com
      eventTime: "2022-11-21 18:06:52"
      eventType: AwsApiCall
      eventVersion: "1.08"
      managementEvent: true
      p_any_aws_account_ids:
        - "123456789123"
      p_any_aws_arns:
        - arn:aws:iam::123456789123:role/TestUser
        - arn:aws:sts::123456789123:assumed-role/TestUser/test_123456789123
      p_any_ip_addresses:
        - 1.1.1.1
      p_any_trace_ids:
        - ASIA3JHVJH35KB7LJHV2
      p_any_usernames:
        - TestUser
      p_event_time: "2022-11-21 18:06:52"
      p_log_type: AWS.CloudTrail
      p_parse_time: "2022-11-21 18:07:38.9"
      p_row_id: 824956f0377f98908684d8de14d3d612
      p_source_id: 5f9f0f60-9c56-4027-b93a-8bab3019f0f1
      p_source_label: Cloudtrail
      readOnly: true
      recipientAccountId: "123456789123"
      requestID: 1c40241b-c59c-4d4a-8301-b612545f9c5c
      requestParameters:
        accountId: "123456789123"
      sourceIPAddress: 1.1.1.1
      tlsDetails:
        cipherSuite: ECDHE-RSA-AES128-GCM-SHA256
        clientProvidedHostHeader: organizations.us-east-1.amazonaws.com
        tlsVersion: TLSv1.2
      userAgent: Boto3/1.26.2 Python/3.10.8 Linux/4.14.294-220.533.amzn2.x86_64 exec-env/AWS_ECS_FARGATE Botocore/1.29.2
      userIdentity:
        accessKeyId: ASIA3JHVJH35KB7LJHV2
        accountId: "123456789123"
        arn: arn:aws:sts::123456789123:assumed-role/TestUser/test_123456789123
        principalId: AR0A354LKJXC87G9XC89V:test_123456789123
        sessionContext:
          attributes:
            creationDate: "2022-11-21T18:06:36Z"
            mfaAuthenticated: "false"
          sessionIssuer:
            accountId: "123456789123"
            arn: arn:aws:iam::123456789123:role/TestUser
            principalId: AR0A354LKJXC87G9XC89V
            type: Role
            userName: TestUser
          webIdFederationData: {}
        type: AssumedRole
    Name: DescribeAccount
  - ExpectedResult: true
    Log:
      awsRegion: us-east-1
      eventCategory: Management
      eventID: cd05c51d-fee2-4003-b9c5-385f28ad5b29
      eventName: GetAlternateContact
      eventSource: billingconsole.amazonaws.com
      eventTime: "2022-11-23 21:06:45"
      eventType: AwsConsoleAction
      eventVersion: "1.08"
      managementEvent: true
      p_any_aws_account_ids:
        - "123456789123"
      p_any_aws_arns:
        - arn:aws:sts::123456789123:assumed-role/DevAdministrator/test_user
      p_any_ip_addresses:
        - 1.1.1.1
      p_any_trace_ids:
        - ASIA3JHVJH35KB7LJHV2
      p_event_time: "2022-11-23 21:06:45"
      p_log_type: AWS.CloudTrail
      p_parse_time: "2022-11-23 21:08:20.503"
      p_row_id: be1f79935716d5c6faf68be41493e410
      p_source_id: 125a8146-e3ea-454b-aed7-9e08e735b670
      p_source_label: CloudTrail
      readOnly: true
      recipientAccountId: "123456789123"
      requestParameters:
        map: {}
      sourceIPAddress: 1.1.1.1
      tlsDetails:
        cipherSuite: ECDHE-RSA-AES128-GCM-SHA256
        clientProvidedHostHeader: us-east-1.console.aws.amazon.com
        tlsVersion: TLSv1.2
      userAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Safari/537.36
      userIdentity:
        accessKeyId: ASIA3JHVJH35KB7LJHV2
        accountId: "123456789123"
        arn: arn:aws:sts::123456789123:assumed-role/DevAdministrator/test_user
        principalId: AR0A354LKJXC87G9XC89V:test_user
        type: AssumedRole
    Name: GetAlternateContact
  - ExpectedResult: true
    Log:
      awsRegion: us-east-1
      eventCategory: Management
      eventID: 743a109a-3bce-4298-8828-114c11339119
      eventName: GetContactInformation
      eventSource: billingconsole.amazonaws.com
      eventTime: "2022-11-23 21:06:46"
      eventType: AwsConsoleAction
      eventVersion: "1.08"
      managementEvent: true
      p_any_aws_account_ids:
        - "123456789123"
      p_any_aws_arns:
        - arn:aws:sts::123456789123:assumed-role/DevAdministrator/test_user
      p_any_ip_addresses:
        - 1.1.1.1
      p_any_trace_ids:
        - ASIA3JHVJH35KB7LJHV2
      p_event_time: "2022-11-23 21:06:46"
      p_log_type: AWS.CloudTrail
      p_parse_time: "2022-11-23 21:08:20.502"
      p_row_id: be1f79935716d5c6faf68be4148ce410
      p_source_id: 125a8146-e3ea-454b-aed7-9e08e735b670
      p_source_label: Panther Identity Org CloudTrail
      readOnly: true
      recipientAccountId: "123456789123"
      requestParameters:
        map:
          type: CONTACT
      sourceIPAddress: 1.1.1.1
      tlsDetails:
        cipherSuite: ECDHE-RSA-AES128-GCM-SHA256
        clientProvidedHostHeader: us-east-1.console.aws.amazon.com
        tlsVersion: TLSv1.2
      userAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Safari/537.36
      userIdentity:
        accessKeyId: ASIA3JHVJH35KB7LJHV2
        accountId: "123456789123"
        arn: arn:aws:sts::123456789123:assumed-role/DevAdministrator/test_user
        principalId: AR0A354LKJXC87G9XC89V:test_user
        type: AssumedRole
    Name: GetContactInformation
DedupPeriodMinutes: 60
LogTypes:
  - AWS.CloudTrail
RuleID: "AWS.CloudTrail.Account.Discovery"
Threshold: 1

Detection logic

Condition

eventName in ["GetAlternateContact", "GetContactInformation", "PutAlternateContact", "PutContactInformation", "DescribeAccount"]

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.

Field	Kind	Values
`eventName`	in	`DescribeAccount` `GetAlternateContact` `GetContactInformation` `PutAlternateContact` `PutContactInformation`

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`arn`	`userIdentity.arn`
`eventName`
`recipientAccountId`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)