Creating keys with encrypt policy without MFA

Back


Id	454133a7-5427-4a7c-bdc4-0adfa84dda16
Rulename	Creating keys with encrypt policy without MFA
Description	Detection of KMS keys where action kms:Encrypt is accessible for everyone (also outside of your organization). This is an idicator that your account is compromised and the attacker uses the encryption key to compromise another company.
Severity	Medium
Tactics	Impact
Techniques	T1485
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_CreationofEncryptKeysWithoutMFA.yaml
Version	1.0.2
Arm template	454133a7-5427-4a7c-bdc4-0adfa84dda16.json

KQL

let check_actions = AWSCloudTrail
| where (EventName == "CreateKey" or EventName == "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 == "kms:Encrypt" or Action == "kms:*") and (Effect == 'Allow') and (Principal has "*")
| distinct AwsEventId;
AWSCloudTrail
| where (EventName == "CreateKey" or EventName == "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

YAML

status: Available
triggerOperator: gt
triggerThreshold: 0
name: Creating keys with encrypt policy without MFA
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_CreationofEncryptKeysWithoutMFA.yaml
queryPeriod: 1d
severity: Medium
kind: Scheduled
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  - columnName: RecipientAccountId
    identifier: CloudAppAccountId
- entityType: IP
  fieldMappings:
  - columnName: SourceIpAddress
    identifier: Address
queryFrequency: 1d
relevantTechniques:
- T1485
requiredDataConnectors:
- dataTypes:
  - AWSCloudTrail
  connectorId: AWS
description: |
    'Detection of KMS keys where action kms:Encrypt is accessible for everyone (also outside of your organization). This is an idicator that your account is compromised and the attacker uses the encryption key to compromise another company.'
tactics:
- Impact
query: |
  let check_actions = AWSCloudTrail
  | where (EventName == "CreateKey" or EventName == "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 == "kms:Encrypt" or Action == "kms:*") and (Effect == 'Allow') and (Principal has "*")
  | distinct AwsEventId;
  AWSCloudTrail
  | where (EventName == "CreateKey" or EventName == "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  
id: 454133a7-5427-4a7c-bdc4-0adfa84dda16
version: 1.0.2

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/454133a7-5427-4a7c-bdc4-0adfa84dda16')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/454133a7-5427-4a7c-bdc4-0adfa84dda16')]",
      "properties": {
        "alertRuleTemplateName": "454133a7-5427-4a7c-bdc4-0adfa84dda16",
        "customDetails": null,
        "description": "'Detection of KMS keys where action kms:Encrypt is accessible for everyone (also outside of your organization). This is an idicator that your account is compromised and the attacker uses the encryption key to compromise another company.'\n",
        "displayName": "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 Web Services/Analytic Rules/AWS_CreationofEncryptKeysWithoutMFA.yaml",
        "query": "let check_actions = AWSCloudTrail\n| where (EventName == \"CreateKey\" or EventName == \"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 == \"kms:Encrypt\" or Action == \"kms:*\") and (Effect == 'Allow') and (Principal has \"*\")\n| distinct AwsEventId;\nAWSCloudTrail\n| where (EventName == \"CreateKey\" or EventName == \"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": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}