AWS CloudFormation Stack Drift

Severity: low
Tags: AWS, Operations, Panther, Impact:Resource Hijacking
Reference: https://amzn.to/2z8dDFW
Source: github.com/panther-labs/panther-analysis

A stack has drifted from its defined configuration.

MITRE ATT&CK coverage

Tactic	Techniques
Impact	`T1496` Resource Hijacking

Rule body yaml

AnalysisType: policy
Filename: aws_cloudformation_stack_drifted.py
PolicyID: "AWS.CloudFormation.Stack.Drifted"
DisplayName: "AWS CloudFormation Stack Drift"
Enabled: true
ResourceTypes:
  - AWS.CloudFormation.Stack
Reports:
  MITRE ATT&CK:
    - TA0040:T1496
Tags:
  - AWS
  - Operations
  - Panther
  - Impact:Resource Hijacking
Severity: Low
Description: >
  A stack has drifted from its defined configuration.
Runbook: |
  From the CloudFormation web console, look at the drifted resources for the failing stack.
  If the drift is expected, update the policy ignore list to exclude this stack.
  Otherwise, analyze CloudTrail logs to understand who changed the drifted resource(s) and ensure
  it was legitimate access.
Reference: https://amzn.to/2z8dDFW
Tests:
  - Name: Stack Drifted
    ExpectedResult: false
    Resource:
      {
        "AccountId": "123456789012",
        "Region": "us-west-2",
        "ARN": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "ID": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "Name": "iam-roles",
        "Tags": {},
        "ResourceID": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "ResourceType": "AWS.CloudFormation.Stack",
        "TimeCreated": "2019-04-02T17:16:30.000Z",
        "Capabilities": ["CAPABILITY_NAMED_IAM"],
        "ChangeSetId": null,
        "DeletionTime": null,
        "Description": "IAM Admin role",
        "DisableRollback": false,
        "DriftInformation":
          {
            "LastCheckTimestamp": "2019-04-02T17:16:30Z",
            "StackDriftStatus": "DRIFTED",
          },
        "EnableTerminationProtection": null,
        "LastUpdatedTime": "2019-04-02T17:16:30Z",
        "NotificationARNs": [],
        "Outputs": null,
        "Parameters":
          [
            {
              "ParameterKey": "MaxSessionDurationSec",
              "ParameterValue": "28800",
              "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/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "StackStatus": "UPDATE_COMPLETE",
        "StackStatusReason": null,
        "TimeoutInMinutes": null,
        "Drifts": [],
      }
  - Name: Stack Drifted but Ignored
    ExpectedResult: true
    Resource:
      {
        "AccountId": "123456789012",
        "Region": "us-west-2",
        "ARN": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "ID": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "Name": "panther-master-Panther-XXXXXXXXXXXXX-BootstrapGateway-XXXXXXXXXXXXX",
        "Tags":
          {
            "Application": "Panther",
            "PantherEdition": "Community",
            "PantherVersion": "v1.7.1",
            "Stack": "panther-bootstrap-gateway",
          },
        "ResourceID": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "ResourceType": "AWS.CloudFormation.Stack",
        "TimeCreated": "2019-04-02T17:16:30.000Z",
        "Capabilities": ["CAPABILITY_NAMED_IAM"],
        "ChangeSetId": null,
        "DeletionTime": null,
        "Description": "IAM Admin role",
        "DisableRollback": false,
        "DriftInformation":
          {
            "LastCheckTimestamp": "2019-04-02T17:16:30Z",
            "StackDriftStatus": "DRIFTED",
          },
        "EnableTerminationProtection": null,
        "LastUpdatedTime": "2019-04-02T17:16:30Z",
        "NotificationARNs": [],
        "Outputs": null,
        "Parameters":
          [
            {
              "ParameterKey": "MaxSessionDurationSec",
              "ParameterValue": "28800",
              "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/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "StackStatus": "UPDATE_COMPLETE",
        "StackStatusReason": null,
        "TimeoutInMinutes": null,
        "Drifts": [],
      }
  - Name: Stack In Sync
    ExpectedResult: true
    Resource:
      {
        "AccountId": "123456789012",
        "Region": "us-west-2",
        "ARN": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "ID": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "Name": "iam-roles",
        "Tags": {},
        "ResourceID": "arn:aws:cloudformation:us-west-2:123456789012:stack/iam-roles/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "ResourceType": "AWS.CloudFormation.Stack",
        "TimeCreated": "2019-04-02T17:16:30.000Z",
        "Capabilities": ["CAPABILITY_NAMED_IAM"],
        "ChangeSetId": null,
        "DeletionTime": null,
        "Description": "IAM Admin role",
        "DisableRollback": false,
        "DriftInformation":
          {
            "LastCheckTimestamp": "2019-04-02T17:16:30Z",
            "StackDriftStatus": "IN_SYNC",
          },
        "EnableTerminationProtection": null,
        "LastUpdatedTime": "2019-04-02T17:16:30Z",
        "NotificationARNs": [],
        "Outputs": null,
        "Parameters":
          [
            {
              "ParameterKey": "MaxSessionDurationSec",
              "ParameterValue": "28800",
              "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/12345678901258f4c3a3-c67c-4f81-afe1-509a2065de91",
        "StackStatus": "UPDATE_COMPLETE",
        "StackStatusReason": null,
        "TimeoutInMinutes": null,
        "Drifts": [],
      }

Detection logic

Condition

not (DriftInformation.StackDriftStatus ne "DRIFTED" or (Tags.Application eq "Panther" and Tags.Stack in ["panther-bootstrap-gateway", "panther-cloud-security", "panther-core", "panther-log-analysis"]))

Exclusions

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

Field	Kind	Excluded values
`Tags.Application`	eq	`Panther`
`Tags.Stack`	in	`panther-bootstrap-gateway`, `panther-cloud-security`, `panther-core`, `panther-log-analysis`
`DriftInformation.StackDriftStatus`	ne	`DRIFTED`

`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 Drift

MITRE ATT&CK coverage

Rule body yaml

Detection logic

Condition

Exclusions

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