AWSCloudTrail - Created CRUD S3 policy and then privilege escalation

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Id	467cbe7e-e6d4-4f4e-8e44-84dd01932c32
Rulename	AWSCloudTrail - Created CRUD S3 policy and then privilege escalation
Description	Identifies creation of IAM policies that grant broad Amazon S3 CRUD permissions, followed by policy attachment activity to users, roles, or groups. This sequence can indicate attempts to expand access and should be investigated as potential cloud privilege escalation.
Severity	Medium
Tactics	DefenseEvasion PrivilegeEscalation Persistence
Techniques	T1484 T1098.003
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%20Web%20Services/Analytic%20Rules/AWS_CreatedCRUDS3PolicytoPrivilegeEscalation.yaml
Version	1.0.3
Arm template	467cbe7e-e6d4-4f4e-8e44-84dd01932c32.json

KQL

let EventNameList = dynamic(["AttachUserPolicy","AttachRolePolicy","AttachGroupPolicy"]);
let createPolicy =  dynamic(["CreatePolicy", "CreatePolicyVersion"]);
let timeframe = 1d;
let lookback = 14d;
// Creating Master table with all the events to use with materialize for better performance
let EventInfo = AWSCloudTrail
| where TimeGenerated >= ago(lookback)
| where EventName in (EventNameList) or EventName in (createPolicy)
| 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]), "");
//Checking for Policy creation event with Full Admin Privileges since lookback period.
let FullAdminPolicyEvents =  materialize(  EventInfo
| where TimeGenerated >= ago(lookback)
| where EventName in (createPolicy)
| extend PolicyName = tostring(parse_json(RequestParameters).policyName)
| extend Statement = parse_json(tostring((parse_json(RequestParameters).policyDocument))).Statement
| mvexpand Statement
| extend Action = parse_json(Statement).Action , Effect = tostring(parse_json(Statement).Effect), Resource = tostring(parse_json(Statement).Resource), Condition = tostring(parse_json(Statement).Condition)
| extend Action = tostring(Action)
| where Effect =~ "Allow" and (Action contains "s3:Create" and Action contains "s3:Get" and Action contains "s3:Put" and Action contains "s3:Delete") and Resource == "*" and Condition == ""
| distinct TimeGenerated, EventName, PolicyName, SourceIpAddress, UserIdentityArn, RecipientAccountId, AccountName, AccountUPNSuffix
| project-rename StartTime = TimeGenerated  );
let PolicyAttach = materialize(  EventInfo
| where TimeGenerated >= ago(timeframe)
| where EventName in (EventNameList) and isempty(ErrorCode) and isempty(ErrorMessage)
| extend PolicyName = tostring(split(tostring(parse_json(RequestParameters).policyArn),"/")[1])
| summarize AttachEventCount=count(), StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by EventSource, EventName, UserIdentityType , UserIdentityArn, SourceIpAddress, RecipientAccountId, AccountName, AccountUPNSuffix, PolicyName
| extend AttachEvent = pack("StartTime", StartTime, "EndTime", EndTime, "EventName", EventName, "UserIdentityType",   UserIdentityType, "SourceIpAddress", SourceIpAddress, "AccountName", AccountName, "AccountUPNSuffix", AccountUPNSuffix, "RecipientAccountId", RecipientAccountId, "UserIdentityArn", UserIdentityArn)
| project EventSource, PolicyName, AttachEvent, AttachEventCount, RecipientAccountId, AccountName, AccountUPNSuffix
);
// Joining the list of PolicyNames and checking if it has been attached to any Roles/Users/Groups.
// These Roles/Users/Groups will be Privileged and can be used by adversaries as pivot point for privilege escalation via multiple ways.
FullAdminPolicyEvents
| join kind=leftouter
(
    PolicyAttach
)
on PolicyName
| project-away PolicyName1

YAML

tactics:
- DefenseEvasion
- PrivilegeEscalation
- Persistence
requiredDataConnectors:
- dataTypes:
  - AWSCloudTrail
  connectorId: AWS
queryPeriod: 1d
kind: Scheduled
severity: Medium
customDetails:
  EventName: EventName
  PolicyName: PolicyName
  RecipientAccountId: RecipientAccountId
  UserIdentityArn: UserIdentityArn
queryFrequency: 1d
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon%20Web%20Services/Analytic%20Rules/AWS_CreatedCRUDS3PolicytoPrivilegeEscalation.yaml
triggerThreshold: 0
description: |
  Identifies creation of IAM policies that grant broad Amazon S3 CRUD permissions, followed by policy attachment activity to users, roles, or groups. This sequence can indicate attempts to
  expand access and should be investigated as potential cloud privilege escalation.
id: 467cbe7e-e6d4-4f4e-8e44-84dd01932c32
triggerOperator: gt
alertDetailsOverride:
  alertDescriptionFormat: Detected {{EventName}} for policy {{PolicyName}} in account {{RecipientAccountId}}.
  alertDisplayNameFormat: 'AWS S3 privilege escalation policy activity: {{PolicyName}} by {{AccountName}}'
status: Available
relevantTechniques:
- T1484
- T1098.003
version: 1.0.3
name: AWSCloudTrail - Created CRUD S3 policy and then privilege escalation
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  - columnName: RecipientAccountId
    identifier: CloudAppAccountId
- entityType: IP
  fieldMappings:
  - columnName: SourceIpAddress
    identifier: Address
query: |
  let EventNameList = dynamic(["AttachUserPolicy","AttachRolePolicy","AttachGroupPolicy"]);
  let createPolicy =  dynamic(["CreatePolicy", "CreatePolicyVersion"]);
  let timeframe = 1d;
  let lookback = 14d;
  // Creating Master table with all the events to use with materialize for better performance
  let EventInfo = AWSCloudTrail
  | where TimeGenerated >= ago(lookback)
  | where EventName in (EventNameList) or EventName in (createPolicy)
  | 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]), "");
  //Checking for Policy creation event with Full Admin Privileges since lookback period.
  let FullAdminPolicyEvents =  materialize(  EventInfo
  | where TimeGenerated >= ago(lookback)
  | where EventName in (createPolicy)
  | extend PolicyName = tostring(parse_json(RequestParameters).policyName)
  | extend Statement = parse_json(tostring((parse_json(RequestParameters).policyDocument))).Statement
  | mvexpand Statement
  | extend Action = parse_json(Statement).Action , Effect = tostring(parse_json(Statement).Effect), Resource = tostring(parse_json(Statement).Resource), Condition = tostring(parse_json(Statement).Condition)
  | extend Action = tostring(Action)
  | where Effect =~ "Allow" and (Action contains "s3:Create" and Action contains "s3:Get" and Action contains "s3:Put" and Action contains "s3:Delete") and Resource == "*" and Condition == ""
  | distinct TimeGenerated, EventName, PolicyName, SourceIpAddress, UserIdentityArn, RecipientAccountId, AccountName, AccountUPNSuffix
  | project-rename StartTime = TimeGenerated  );
  let PolicyAttach = materialize(  EventInfo
  | where TimeGenerated >= ago(timeframe)
  | where EventName in (EventNameList) and isempty(ErrorCode) and isempty(ErrorMessage)
  | extend PolicyName = tostring(split(tostring(parse_json(RequestParameters).policyArn),"/")[1])
  | summarize AttachEventCount=count(), StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by EventSource, EventName, UserIdentityType , UserIdentityArn, SourceIpAddress, RecipientAccountId, AccountName, AccountUPNSuffix, PolicyName
  | extend AttachEvent = pack("StartTime", StartTime, "EndTime", EndTime, "EventName", EventName, "UserIdentityType",   UserIdentityType, "SourceIpAddress", SourceIpAddress, "AccountName", AccountName, "AccountUPNSuffix", AccountUPNSuffix, "RecipientAccountId", RecipientAccountId, "UserIdentityArn", UserIdentityArn)
  | project EventSource, PolicyName, AttachEvent, AttachEventCount, RecipientAccountId, AccountName, AccountUPNSuffix
  );
  // Joining the list of PolicyNames and checking if it has been attached to any Roles/Users/Groups.
  // These Roles/Users/Groups will be Privileged and can be used by adversaries as pivot point for privilege escalation via multiple ways.
  FullAdminPolicyEvents
  | join kind=leftouter
  (
      PolicyAttach
  )
  on PolicyName
  | project-away PolicyName1

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/467cbe7e-e6d4-4f4e-8e44-84dd01932c32')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/467cbe7e-e6d4-4f4e-8e44-84dd01932c32')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "Detected {{EventName}} for policy {{PolicyName}} in account {{RecipientAccountId}}.",
          "alertDisplayNameFormat": "AWS S3 privilege escalation policy activity: {{PolicyName}} by {{AccountName}}"
        },
        "alertRuleTemplateName": "467cbe7e-e6d4-4f4e-8e44-84dd01932c32",
        "customDetails": {
          "EventName": "EventName",
          "PolicyName": "PolicyName",
          "RecipientAccountId": "RecipientAccountId",
          "UserIdentityArn": "UserIdentityArn"
        },
        "description": "Identifies creation of IAM policies that grant broad Amazon S3 CRUD permissions, followed by policy attachment activity to users, roles, or groups. This sequence can indicate attempts to\nexpand access and should be investigated as potential cloud privilege escalation.\n",
        "displayName": "AWSCloudTrail - Created CRUD S3 policy and then privilege escalation",
        "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_CreatedCRUDS3PolicytoPrivilegeEscalation.yaml",
        "query": "let EventNameList = dynamic([\"AttachUserPolicy\",\"AttachRolePolicy\",\"AttachGroupPolicy\"]);\nlet createPolicy =  dynamic([\"CreatePolicy\", \"CreatePolicyVersion\"]);\nlet timeframe = 1d;\nlet lookback = 14d;\n// Creating Master table with all the events to use with materialize for better performance\nlet EventInfo = AWSCloudTrail\n| where TimeGenerated >= ago(lookback)\n| where EventName in (EventNameList) or EventName in (createPolicy)\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//Checking for Policy creation event with Full Admin Privileges since lookback period.\nlet FullAdminPolicyEvents =  materialize(  EventInfo\n| where TimeGenerated >= ago(lookback)\n| where EventName in (createPolicy)\n| extend PolicyName = tostring(parse_json(RequestParameters).policyName)\n| extend Statement = parse_json(tostring((parse_json(RequestParameters).policyDocument))).Statement\n| mvexpand Statement\n| extend Action = parse_json(Statement).Action , Effect = tostring(parse_json(Statement).Effect), Resource = tostring(parse_json(Statement).Resource), Condition = tostring(parse_json(Statement).Condition)\n| extend Action = tostring(Action)\n| where Effect =~ \"Allow\" and (Action contains \"s3:Create\" and Action contains \"s3:Get\" and Action contains \"s3:Put\" and Action contains \"s3:Delete\") and Resource == \"*\" and Condition == \"\"\n| distinct TimeGenerated, EventName, PolicyName, SourceIpAddress, UserIdentityArn, RecipientAccountId, AccountName, AccountUPNSuffix\n| project-rename StartTime = TimeGenerated  );\nlet PolicyAttach = materialize(  EventInfo\n| where TimeGenerated >= ago(timeframe)\n| where EventName in (EventNameList) and isempty(ErrorCode) and isempty(ErrorMessage)\n| extend PolicyName = tostring(split(tostring(parse_json(RequestParameters).policyArn),\"/\")[1])\n| summarize AttachEventCount=count(), StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by EventSource, EventName, UserIdentityType , UserIdentityArn, SourceIpAddress, RecipientAccountId, AccountName, AccountUPNSuffix, PolicyName\n| extend AttachEvent = pack(\"StartTime\", StartTime, \"EndTime\", EndTime, \"EventName\", EventName, \"UserIdentityType\",   UserIdentityType, \"SourceIpAddress\", SourceIpAddress, \"AccountName\", AccountName, \"AccountUPNSuffix\", AccountUPNSuffix, \"RecipientAccountId\", RecipientAccountId, \"UserIdentityArn\", UserIdentityArn)\n| project EventSource, PolicyName, AttachEvent, AttachEventCount, RecipientAccountId, AccountName, AccountUPNSuffix\n);\n// Joining the list of PolicyNames and checking if it has been attached to any Roles/Users/Groups.\n// These Roles/Users/Groups will be Privileged and can be used by adversaries as pivot point for privilege escalation via multiple ways.\nFullAdminPolicyEvents\n| join kind=leftouter\n(\n    PolicyAttach\n)\non PolicyName\n| project-away PolicyName1\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [
          "T1098.003"
        ],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion",
          "Persistence",
          "PrivilegeEscalation"
        ],
        "techniques": [
          "T1098",
          "T1484"
        ],
        "templateVersion": "1.0.3",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}