AWS IAM Policy Blocklist

Severity: medium
Tags: AWS, Configuration Required, Identity & Access Management, Privilege Escalation:Valid Accounts
Reference: https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies.html
Source: github.com/panther-labs/panther-analysis

This detects the usage of highly permissive IAM Policies that should only be assigned to a small number of users, roles, or groups.

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1078` Valid Accounts

Rule body yaml

AnalysisType: policy
Filename: aws_iam_policy_blocklist.py
PolicyID: "AWS.IAM.Policy.Blacklist"
DisplayName: "AWS IAM Policy Blocklist"
Enabled: false
ResourceTypes:
  - AWS.IAM.Group
  - AWS.IAM.Role
  - AWS.IAM.User
Reports:
  MITRE ATT&CK:
    - TA0004:T1078
Tags:
  - AWS
  - Configuration Required
  - Identity & Access Management
  - Privilege Escalation:Valid Accounts
Severity: Medium
Description: >
  This detects the usage of highly permissive IAM Policies that should only be assigned to a small number of users, roles, or groups.
Runbook: >
  https://docs.runpanther.io/alert-runbooks/built-in-policies/aws-iam-policy-blacklist-is-respected
Reference: https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies.html
Tests:
  - Name: IAM User Does Not Have Blocklisted Policy
    ExpectedResult: true
    Resource:
      {
        "Arn": "arn:aws:iam::123456789012:user/Bobert",
        "CreateDate": "2019-01-01T00:00:00Z",
        "CredentialReport":
          {
            "ARN": "arn:aws:iam::123456789012:user/Bobert",
            "AccessKey1Active": true,
            "AccessKey1LastRotated": "2019-01-01T00:00:00Z",
            "AccessKey1LastUsedDate": "0001-01-01T00:00:00Z",
            "AccessKey1LastUsedRegion": "N/A",
            "AccessKey1LastUsedService": "N/A",
            "AccessKey2Active": false,
            "AccessKey2LastRotated": "0001-01-01T00:00:00Z",
            "AccessKey2LastUsedDate": "0001-01-01T00:00:00Z",
            "AccessKey2LastUsedRegion": "N/A",
            "AccessKey2LastUsedService": "N/A",
            "Cert1Active": false,
            "Cert1LastRotated": "0001-01-01T00:00:00Z",
            "Cert2Active": false,
            "Cert2LastRotated": "0001-01-01T00:00:00Z",
            "MfaActive": false,
            "PasswordEnabled": true,
            "PasswordLastChanged": "2019-01-01T00:00:00Z",
            "PasswordLastUsed": "0001-01-01T00:00:00Z",
            "PasswordNextRotation": "2019-04-01T00:00:00Z",
            "UserCreationTime": "2019-01-01T00:00:00Z",
            "UserName": "Bobert",
          },
        "Groups":
          [
            {
              "Arn": "arn:aws:iam::123456789012:group/ExampleGroup",
              "CreateDate": "2019-01-01T00:00:00Z",
              "GroupId": "ABCDEFGHIJKLMNOP",
              "GroupName": "ExampleGroup",
              "Path": "/",
            },
          ],
        "InlinePolicyNames": null,
        "ManagedPolicyNames": ["TEST_NOT_BLOCKLISTED_ARN"],
        "PasswordLastUsed": null,
        "Path": "/",
        "PermissionsBoundary": null,
        "Tags": null,
        "UserId": "ASDFASDFASDFASDF",
        "UserName": "Bobert",
        "VirtualMFA": null,
      }
  - Name: IAM User Has Blocklisted Policy
    ExpectedResult: false
    Resource:
      {
        "Arn": "arn:aws:iam::123456789012:user/Bobert",
        "CreateDate": "2019-01-01T00:00:00Z",
        "CredentialReport":
          {
            "ARN": "arn:aws:iam::123456789012:user/Bobert",
            "AccessKey1Active": true,
            "AccessKey1LastRotated": "2019-01-01T00:00:00Z",
            "AccessKey1LastUsedDate": "0001-01-01T00:00:00Z",
            "AccessKey1LastUsedRegion": "N/A",
            "AccessKey1LastUsedService": "N/A",
            "AccessKey2Active": false,
            "AccessKey2LastRotated": "0001-01-01T00:00:00Z",
            "AccessKey2LastUsedDate": "0001-01-01T00:00:00Z",
            "AccessKey2LastUsedRegion": "N/A",
            "AccessKey2LastUsedService": "N/A",
            "Cert1Active": false,
            "Cert1LastRotated": "0001-01-01T00:00:00Z",
            "Cert2Active": false,
            "Cert2LastRotated": "0001-01-01T00:00:00Z",
            "MfaActive": false,
            "PasswordEnabled": true,
            "PasswordLastChanged": "2019-01-01T00:00:00Z",
            "PasswordLastUsed": "0001-01-01T00:00:00Z",
            "PasswordNextRotation": "2019-04-01T00:00:00Z",
            "UserCreationTime": "2019-01-01T00:00:00Z",
            "UserName": "Bobert",
          },
        "Groups":
          [
            {
              "Arn": "arn:aws:iam::123456789012:group/ExampleGroup",
              "CreateDate": "2019-01-01T00:00:00Z",
              "GroupId": "ABCDEFGHIJKLMNOP",
              "GroupName": "ExampleGroup",
              "Path": "/",
            },
          ],
        "InlinePolicyNames": null,
        "ManagedPolicyNames": ["TEST_BLOCKLISTED_ARN"],
        "PasswordLastUsed": null,
        "Path": "/",
        "PermissionsBoundary": null,
        "Tags": null,
        "UserId": "ASDFASDFASDFASDF",
        "UserName": "Bobert",
        "VirtualMFA": null,
      }

Detection logic

Condition

not (ManagedPolicyNames not contains "TEST_BLOCKLISTED_ARN" and ManagedPolicyNames is_null)

Exclusions

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

Field	Kind	Excluded values
`ManagedPolicyNames`	contains	`TEST_BLOCKLISTED_ARN`
`ManagedPolicyNames`	is_null	(no value, null check)

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
`ManagedPolicyNames`	contains	`TEST_BLOCKLISTED_ARN`

`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)