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	1.0.2
Arm template	60dfc193-0f73-4279-b43c-110ade02b201.json

KQL

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 == "kms:Encrypt" or Action == "kms:*") 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

relevantTechniques:
- T1486
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_OverlyPermessiveKMS.yaml
triggerOperator: gt
kind: Scheduled
entityMappings:
- fieldMappings:
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  - columnName: RecipientAccountId
    identifier: CloudAppAccountId
  entityType: Account
- fieldMappings:
  - columnName: SourceIpAddress
    identifier: Address
  entityType: IP
requiredDataConnectors:
- dataTypes:
  - AWSCloudTrail
  connectorId: AWS
queryPeriod: 1d
query: |
  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 == "kms:Encrypt" or Action == "kms:*") 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  
version: 1.0.2
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.'
tactics:
- Impact
severity: High
name: Suspicious overly permissive KMS key policy created
queryFrequency: 1d
triggerThreshold: 0
status: Available
id: 60dfc193-0f73-4279-b43c-110ade02b201

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-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": "AWSCloudTrail\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 == \"kms:Encrypt\" or Action == \"kms:*\") 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",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "techniques": [
          "T1486"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}