Suspicious overly permissive KMS key policy created

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Id	60dfc193-0f73-4279-b43c-110ade02b201
Rulename	Suspicious overly permissive KMS key policy created
Description	An overly permissive key policy was created, resulting in KMS keys where the kms:Encrypt action is accessible to everyone (even outside of the organization). This could mean that your account is compromised and that the attacker is using the encryption key to compromise other organizations.
Severity	High
Tactics	Impact
Techniques	T1486
Required data connectors	AWS
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_OverlyPermessiveKMS.yaml
Version	1.0.4
Arm template	60dfc193-0f73-4279-b43c-110ade02b201.json

KQL

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]), "")
| extend timestamp = TimeGenerated

YAML

name: Suspicious overly permissive KMS key policy created
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_OverlyPermessiveKMS.yaml
queryPeriod: 1d
version: 1.0.4
severity: High
id: 60dfc193-0f73-4279-b43c-110ade02b201
triggerOperator: gt
triggerThreshold: 0
kind: Scheduled
requiredDataConnectors:
- dataTypes:
  - AWSCloudTrail
  connectorId: AWS
relevantTechniques:
- T1486
description: |
    'An overly permissive key policy was created, resulting in KMS keys where the kms:Encrypt action is accessible to everyone (even outside of the organization). This could mean that your account is compromised and that the attacker is using the encryption key to compromise other organizations.'
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]), "")
  | extend timestamp = TimeGenerated  
tactics:
- Impact
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  - columnName: RecipientAccountId
    identifier: CloudAppAccountId
- entityType: IP
  fieldMappings:
  - columnName: SourceIpAddress
    identifier: Address
status: Available
queryFrequency: 1d

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/60dfc193-0f73-4279-b43c-110ade02b201')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/60dfc193-0f73-4279-b43c-110ade02b201')]",
      "properties": {
        "alertRuleTemplateName": "60dfc193-0f73-4279-b43c-110ade02b201",
        "customDetails": null,
        "description": "'An overly permissive key policy was created, resulting in KMS keys where the kms:Encrypt action is accessible to everyone (even outside of the organization). This could mean that your account is compromised and that the attacker is using the encryption key to compromise other organizations.'\n",
        "displayName": "Suspicious overly permissive KMS key policy created",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountUPNSuffix",
                "identifier": "UPNSuffix"
              },
              {
                "columnName": "RecipientAccountId",
                "identifier": "CloudAppAccountId"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SourceIpAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_OverlyPermessiveKMS.yaml",
        "query": "let kmsActions = dynamic([\"kms:Encrypt\", \"kms:*\"]); //Add other overly permissive APIs to this list.\nAWSCloudTrail\n| where EventName in (\"CreateKey\",\"PutKeyPolicy\") and isempty(ErrorCode) and isempty(ErrorMessage)\n| extend Statement = parse_json(tostring((parse_json(RequestParameters).policy))).Statement\n| mvexpand Statement\n| 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))\n| where Effect =~ \"Allow\" and Action has_any (kmsActions) and Principal == \"*\" \n| extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)\n| extend UserName = tostring(split(UserIdentityArn, '/')[-1])\n| extend AccountName = case( UserIdentityPrincipalid == \"Anonymous\", \"Anonymous\", isempty(UserIdentityUserName), UserName, UserIdentityUserName)\n| extend AccountName = iif(AccountName contains \"@\", tostring(split(AccountName, '@', 0)[0]), AccountName),\n  AccountUPNSuffix = iif(AccountName contains \"@\", tostring(split(AccountName, '@', 1)[0]), \"\")\n| extend timestamp = TimeGenerated\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "High",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "techniques": [
          "T1486"
        ],
        "templateVersion": "1.0.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}