AWS CloudFormation Stack IAM Service Role

Severity: informational
Tags: AWS, Operations, Panther
Reference: https://amzn.to/2HAdfny
Source: github.com/panther-labs/panther-analysis

Associating IAM roles with CloudFormation stacks ensures least privilege when making changes to your account.

Rule body yaml

AnalysisType: policy
Filename: aws_cloudformation_stack_uses_iam_role.py
PolicyID: "AWS.CloudFormation.Stack.UsesIAMServiceRole"
DisplayName: "AWS CloudFormation Stack IAM Service Role"
Enabled: true
ResourceTypes:
  - AWS.CloudFormation.Stack
Tags:
  - AWS
  - Operations
  - Panther
Severity: Info
Description: >
  Associating IAM roles with CloudFormation stacks ensures least privilege when making
  changes to your account.
Runbook: >
  Create a new IAM role to be assumable by the cloudformation service, and then update the
  current stack with the --role-arn argument.
Reference: https://amzn.to/2HAdfny
Tests:
  - Name: IAM Service Role Attached
    ExpectedResult: true
    Resource:
      {
        "AccountId": "123456789012",
        "Region": "us-west-2",
        "ARN": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/1",
        "ID": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/1",
        "Name": "iam-roles",
        "Tags": {},
        "ResourceID": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/1",
        "ResourceType": "AWS.CloudFormation.Stack",
        "TimeCreated": "2019-01-01T00:00:00.000Z",
        "Capabilities": ["CAPABILITY_NAMED_IAM"],
        "ChangeSetId": null,
        "DeletionTime": null,
        "Description": "IAM role stack",
        "DisableRollback": false,
        "DriftInformation":
          {
            "LastCheckTimestamp": "2019-01-01T00:00:00Z",
            "StackDriftStatus": "IN-SYNC",
          },
        "EnableTerminationProtection": null,
        "LastUpdatedTime": "2019-01-01T00:00:00Z",
        "NotificationARNs": [],
        "Outputs": null,
        "Parameters":
          [
            {
              "ParameterKey": "MaxSessionDurationSec",
              "ParameterValue": "10000",
              "ResolvedValue": null,
              "UsePreviousValue": null,
            },
            {
              "ParameterKey": "Prefix",
              "ParameterValue": "Dev",
              "ResolvedValue": null,
              "UsePreviousValue": null,
            },
          ],
        "ParentId": null,
        "RoleARN": "arn:aws:iam::123456789012:role/CFNServiceRole",
        "RollbackConfiguration":
          { "MonitoringTimeInMinutes": null, "RollbackTriggers": [] },
        "RootId": null,
        "StackId": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/1",
        "StackStatus": "UPDATE_COMPLETE",
        "StackStatusReason": null,
        "TimeoutInMinutes": null,
        "Drifts": [],
      }
  - Name: No Service Role Provided
    ExpectedResult: false
    Resource:
      {
        "AccountId": "123456789012",
        "Region": "us-west-2",
        "ARN": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/1",
        "ID": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/1",
        "Name": "iam-roles",
        "Tags": {},
        "ResourceID": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/1",
        "ResourceType": "AWS.CloudFormation.Stack",
        "TimeCreated": "2019-01-01T17:16:30.000Z",
        "Capabilities": ["CAPABILITY_NAMED_IAM"],
        "ChangeSetId": null,
        "DeletionTime": null,
        "Description": "IAM role stack",
        "DisableRollback": false,
        "DriftInformation":
          {
            "LastCheckTimestamp": "2019-01-01T00:00:00Z",
            "StackDriftStatus": "IN-SYNC",
          },
        "EnableTerminationProtection": null,
        "LastUpdatedTime": "2019-01-01T00:00:00Z",
        "NotificationARNs": [],
        "Outputs": null,
        "Parameters":
          [
            {
              "ParameterKey": "MaxSessionDurationSec",
              "ParameterValue": "10000",
              "ResolvedValue": null,
              "UsePreviousValue": null,
            },
            {
              "ParameterKey": "Prefix",
              "ParameterValue": "Dev",
              "ResolvedValue": null,
              "UsePreviousValue": null,
            },
          ],
        "ParentId": null,
        "RoleARN": null,
        "RollbackConfiguration":
          { "MonitoringTimeInMinutes": null, "RollbackTriggers": [] },
        "RootId": null,
        "StackId": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/1",
        "StackStatus": "UPDATE_COMPLETE",
        "StackStatusReason": null,
        "TimeoutInMinutes": null,
        "Drifts": [],
      }
  - Name: No Service Role Provided But Stack Is StackSet
    ExpectedResult: true
    Resource:
      {
        "AccountId": "123456789012",
        "Region": "us-west-2",
        "ARN": "arn:aws:cloudformation:us-west-2:123456789012:stack/StackSet-iam-roles/1",
        "ID": "arn:aws:cloudformation:us-west-2:123456789012:stack/StackSet-iam-roles/1",
        "Name": "StackSet-iam-roles",
        "Tags": {},
        "ResourceID": "arn:aws:cloudformation:us-west-2:123456789012:stack/StackSet-iam-roles/1",
        "ResourceType": "AWS.CloudFormation.Stack",
        "TimeCreated": "2019-01-01T00:00:00.000Z",
        "Capabilities": ["CAPABILITY_NAMED_IAM"],
        "ChangeSetId": null,
        "DeletionTime": null,
        "Description": "IAM role stack set",
        "DisableRollback": false,
        "DriftInformation":
          {
            "LastCheckTimestamp": "2019-01-01T00:00:00Z",
            "StackDriftStatus": "IN-SYNC",
          },
        "EnableTerminationProtection": null,
        "LastUpdatedTime": "2019-01-01T00:00:00Z",
        "NotificationARNs": [],
        "Outputs": null,
        "Parameters":
          [
            {
              "ParameterKey": "MaxSessionDurationSec",
              "ParameterValue": "10000",
              "ResolvedValue": null,
              "UsePreviousValue": null,
            },
            {
              "ParameterKey": "Prefix",
              "ParameterValue": "Dev",
              "ResolvedValue": null,
              "UsePreviousValue": null,
            },
          ],
        "ParentId": null,
        "RoleARN": null,
        "RollbackConfiguration":
          { "MonitoringTimeInMinutes": null, "RollbackTriggers": [] },
        "RootId": null,
        "StackStatus": "UPDATE_COMPLETE",
        "StackStatusReason": null,
        "TimeoutInMinutes": null,
        "Drifts": [],
      }

Detection logic

Condition

not (Name starts_with "StackSet-" or RoleARN is_not_null)

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`Name`	starts_with	`StackSet-`
`RoleARN`	is_not_null	(no value, null check)

`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)

AWS CloudFormation Stack IAM Service Role

Rule body yaml

Detection logic

Condition

Exclusions

Keyboard shortcuts

Search operators