AWSCloudTrail - Suspicious overly permissive KMS key policy created

Status: available
Severity: high
Time window: 1d
Source: github.com/Azure/Azure-Sentinel

Detects creation or update of KMS key policies that grant broad encryption permissions to all principals. Overly permissive key policies can be abused for malicious encryption operations and indicate potential account compromise or risky misconfiguration.

MITRE ATT&CK coverage

Tactic	Techniques
Impact	`T1486` Data Encrypted for Impact

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

Rule body kusto

id: 60dfc193-0f73-4279-b43c-110ade02b201
name: AWSCloudTrail - Suspicious overly permissive KMS key policy created
description: |
  Detects creation or update of KMS key policies that grant broad encryption permissions to all principals.
  Overly permissive key policies can be abused for malicious encryption operations and indicate potential account
  compromise or risky misconfiguration.
severity: High
status: Available
requiredDataConnectors:
  - connectorId: AWS
    dataTypes:
      - AWSCloudTrail
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Impact
relevantTechniques:
  - T1486
query: |
    let kmsActions = dynamic(["kms:Encrypt", "kms:*"]); //Add other overly permissive APIs to this list.
    AWSCloudTrail
    | where EventName in ("CreateKey","PutKeyPolicy") and isempty(ErrorCode) and isempty(ErrorMessage)
    | extend Statement = parse_json(tostring((parse_json(RequestParameters).policy))).Statement
    | mvexpand Statement
    | extend Action = tostring(parse_json(Statement).Action), Effect = tostring(parse_json(Statement).Effect), Principal = iff(isnotempty(tostring(parse_json(Statement).Principal.AWS)),tostring(parse_json(Statement).Principal.AWS), tostring(parse_json(Statement).Principal))
    | where Effect =~ "Allow" and Action has_any (kmsActions) and Principal == "*" 
    | extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)
    | extend UserName = tostring(split(UserIdentityArn, '/')[-1])
    | extend AccountName = case( UserIdentityPrincipalid == "Anonymous", "Anonymous", isempty(UserIdentityUserName), UserName, UserIdentityUserName)
    | extend AccountName = iif(AccountName contains "@", tostring(split(AccountName, '@', 0)[0]), AccountName),
      AccountUPNSuffix = iif(AccountName contains "@", tostring(split(AccountName, '@', 1)[0]), "")
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
      - identifier: CloudAppAccountId
        columnName: RecipientAccountId
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIpAddress
customDetails:
  EventName: EventName
  EventSource: EventSource
  AWSRegion: AWSRegion
  UserIdentityArn: UserIdentityArn
alertDetailsOverride:
  alertDisplayNameFormat: 'AWS overly permissive KMS key policy change by {{AccountName}}'
  alertDescriptionFormat: 'Detected {{EventName}} from {{SourceIpAddress}} creating a broadly permissive KMS policy in account {{RecipientAccountId}}.'
version: 1.0.5
kind: Scheduled

Stages and Predicates

Parameters

let kmsActions = dynamic(["kms:Encrypt", "kms:*"]);

Stage 1: `source`

AWSCloudTrail

Stage 2: `where`

| where EventName in ("CreateKey","PutKeyPolicy") and isempty(ErrorCode) and isempty(ErrorMessage)

Stage 3: `extend`

| extend Statement = parse_json(tostring((parse_json(RequestParameters).policy))).Statement

Stage 4: `mv-expand`

| mvexpand Statement

Stage 5: `extend`

| extend Action = tostring(parse_json(Statement).Action), Effect = tostring(parse_json(Statement).Effect), Principal = iff(isnotempty(tostring(parse_json(Statement).Principal.AWS)),tostring(parse_json(Statement).Principal.AWS), tostring(parse_json(Statement).Principal))

Principal =

if/* macro: isnotempty(tostring(parse_json(Statement).Principal.AWS)) */tostring(parse_json(Statement).Principal.AWS)

elsetostring(parse_json(Statement).Principal)

Stage 6: `where`

| where Effect =~ "Allow" and Action has_any (kmsActions) and Principal == "*"

Stage 7: `extend` (4 consecutive steps)

| extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)
| extend UserName = tostring(split(UserIdentityArn, '/')[-1])
| extend AccountName = case( UserIdentityPrincipalid == "Anonymous", "Anonymous", isempty(UserIdentityUserName), UserName, UserIdentityUserName)
| extend AccountName = iif(AccountName contains "@", tostring(split(AccountName, '@', 0)[0]), AccountName),
  AccountUPNSuffix = iif(AccountName contains "@", tostring(split(AccountName, '@', 1)[0]), "")

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
`Action`	match	`kms:*` `kms:Encrypt`
`Effect`	eq	`Allow`
`ErrorCode`	is_null	(no value, null check)
`ErrorMessage`	is_null	(no value, null check)
`EventName`	in	`CreateKey` transforms: `cased` `PutKeyPolicy` transforms: `cased`
`Principal`	eq	`*` transforms: `cased`

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
`Statement`	`extend`
`Action`	`extend`
`Effect`	`extend`
`Principal`	`extend`
`UserIdentityArn`	`extend`
`UserName`	`extend`
`AccountName`	`extend`
`AccountUPNSuffix`	`extend`

`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)

AWSCloudTrail - Suspicious overly permissive KMS key policy created

MITRE ATT&CK coverage

Rules detecting the same action

Rule body kusto

Stages and Predicates

Parameters

Stage 1: `source`

Stage 2: `where`

Stage 3: `extend`

Stage 4: `mv-expand`

Stage 5: `extend`

Stage 6: `where`

Stage 7: `extend` (4 consecutive steps)

Indicators

Output fields

Keyboard shortcuts

Search operators

AWSCloudTrail - Suspicious overly permissive KMS key policy created

MITRE ATT&CK coverage

Rules detecting the same action

Rule body kusto

Stages and Predicates

Parameters

Stage 1: source

Stage 2: where

Stage 3: extend

Stage 4: mv-expand

Stage 5: extend

Stage 6: where

Stage 7: extend (4 consecutive steps)

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `extend`

Stage 4: `mv-expand`

Stage 5: `extend`

Stage 6: `where`

Stage 7: `extend` (4 consecutive steps)