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AWSCloudTrail - Creating keys with encrypt policy without MFA

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Id454133a7-5427-4a7c-bdc4-0adfa84dda16
RulenameAWSCloudTrail - Creating keys with encrypt policy without MFA
DescriptionIdentifies AWS KMS key creation or policy changes that allow `kms:Encrypt` or `kms:*` to any principal. This configuration can expose encryption capability outside approved boundaries and should be investigated as overly permissive or malicious.
SeverityMedium
TacticsImpact
TechniquesT1485
Required data connectorsAWS
KindScheduled
Query frequency1d
Query period1d
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon%20Web%20Services/Analytic%20Rules/AWS_CreationofEncryptKeysWithoutMFA.yaml
Version1.0.3
Arm template454133a7-5427-4a7c-bdc4-0adfa84dda16.json
Deploy To Azure
let check_actions = AWSCloudTrail
| where EventName in ("CreateKey", "PutKeyPolicy") and isempty(ErrorCode) and isempty(ErrorMessage)
| extend state=parse_json(parse_json(replace_string(tostring(parse_json(RequestParameters)['policy']),'\\"','"')).['Statement'])
| mv-expand state
| extend Action= tostring(parse_json(state.['Action'][0])), Effect=tostring(parse_json(state.['Effect'])),
         Principal=tostring(parse_json(state.['Principal']))
| where Action in ("kms:Encrypt", "kms:*") and (Effect == 'Allow') and (Principal has "*")
| distinct AwsEventId;
AWSCloudTrail
| where EventName in ("CreateKey", "PutKeyPolicy") and isempty(ErrorCode) and isempty(ErrorMessage)
| 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]), "")
| join kind=inner (check_actions) on AwsEventId
| extend timestamp = TimeGenerated
| project-away AwsEventId1

alertDetailsOverride:
  alertDescriptionFormat: 'KMS key creation or policy update by {{AccountName}} without MFA resulted in permissive encrypt access. AwsEventId: {{AwsEventId}}'
  alertDisplayNameFormat: AWS KMS key creation or policy update by {{AccountName}} without MFA
requiredDataConnectors:
- connectorId: AWS
  dataTypes:
  - AWSCloudTrail
triggerOperator: gt
queryFrequency: 1d
id: 454133a7-5427-4a7c-bdc4-0adfa84dda16
customDetails:
  UserIdentityArn: UserIdentityArn
  EventName: EventName
  AwsEventId: AwsEventId
tactics:
- Impact
name: AWSCloudTrail - Creating keys with encrypt policy without MFA
version: 1.0.3
triggerThreshold: 0
kind: Scheduled
relevantTechniques:
- T1485
description: |
  Identifies AWS KMS key creation or policy changes that allow `kms:Encrypt` or `kms:*` to any principal. This configuration can expose encryption capability outside approved boundaries and should be investigated as overly permissive or malicious.
severity: Medium
query: |
  let check_actions = AWSCloudTrail
  | where EventName in ("CreateKey", "PutKeyPolicy") and isempty(ErrorCode) and isempty(ErrorMessage)
  | extend state=parse_json(parse_json(replace_string(tostring(parse_json(RequestParameters)['policy']),'\\"','"')).['Statement'])
  | mv-expand state
  | extend Action= tostring(parse_json(state.['Action'][0])), Effect=tostring(parse_json(state.['Effect'])),
           Principal=tostring(parse_json(state.['Principal']))
  | where Action in ("kms:Encrypt", "kms:*") and (Effect == 'Allow') and (Principal has "*")
  | distinct AwsEventId;
  AWSCloudTrail
  | where EventName in ("CreateKey", "PutKeyPolicy") and isempty(ErrorCode) and isempty(ErrorMessage)
  | 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]), "")
  | join kind=inner (check_actions) on AwsEventId
  | extend timestamp = TimeGenerated
  | project-away AwsEventId1
queryPeriod: 1d
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon%20Web%20Services/Analytic%20Rules/AWS_CreationofEncryptKeysWithoutMFA.yaml
entityMappings:
- fieldMappings:
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  - columnName: RecipientAccountId
    identifier: CloudAppAccountId
  entityType: Account
- fieldMappings:
  - columnName: SourceIpAddress
    identifier: Address
  entityType: IP
status: Available

{
  "$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/454133a7-5427-4a7c-bdc4-0adfa84dda16')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/454133a7-5427-4a7c-bdc4-0adfa84dda16')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "KMS key creation or policy update by {{AccountName}} without MFA resulted in permissive encrypt access. AwsEventId: {{AwsEventId}}",
          "alertDisplayNameFormat": "AWS KMS key creation or policy update by {{AccountName}} without MFA"
        },
        "alertRuleTemplateName": "454133a7-5427-4a7c-bdc4-0adfa84dda16",
        "customDetails": {
          "AwsEventId": "AwsEventId",
          "EventName": "EventName",
          "UserIdentityArn": "UserIdentityArn"
        },
        "description": "Identifies AWS KMS key creation or policy changes that allow `kms:Encrypt` or `kms:*` to any principal. This configuration can expose encryption capability outside approved boundaries and should be investigated as overly permissive or malicious.\n",
        "displayName": "AWSCloudTrail - Creating keys with encrypt policy without MFA",
        "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%20Web%20Services/Analytic%20Rules/AWS_CreationofEncryptKeysWithoutMFA.yaml",
        "query": "let check_actions = AWSCloudTrail\n| where EventName in (\"CreateKey\", \"PutKeyPolicy\") and isempty(ErrorCode) and isempty(ErrorMessage)\n| extend state=parse_json(parse_json(replace_string(tostring(parse_json(RequestParameters)['policy']),'\\\\\"','\"')).['Statement'])\n| mv-expand state\n| extend Action= tostring(parse_json(state.['Action'][0])), Effect=tostring(parse_json(state.['Effect'])),\n         Principal=tostring(parse_json(state.['Principal']))\n| where Action in (\"kms:Encrypt\", \"kms:*\") and (Effect == 'Allow') and (Principal has \"*\")\n| distinct AwsEventId;\nAWSCloudTrail\n| where EventName in (\"CreateKey\", \"PutKeyPolicy\") and isempty(ErrorCode) and isempty(ErrorMessage)\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| join kind=inner (check_actions) on AwsEventId\n| extend timestamp = TimeGenerated\n| project-away AwsEventId1\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "techniques": [
          "T1485"
        ],
        "templateVersion": "1.0.3",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}