AWSCloudTrail - Monitor AWS Credential abuse or hijacking

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Id	32555639-b639-4c2b-afda-c0ae0abefa55
Rulename	AWSCloudTrail - Monitor AWS Credential abuse or hijacking
Description	Identifies AWS STS `GetCallerIdentity` calls made by assumed-role sessions. An attacker who has assumed the role of a legitimate account can call the GetCallerIdentity function to determine what account they are using. A legitimate user using legitimate credentials would not need to call GetCallerIdentity since they should already know what account they are using. More Information: https://duo.com/decipher/trailblazer-hunts-compromised-credentials-in-aws AWS STS GetCallerIdentity API: https://docs.aws.amazon.com/STS/latest/APIReference/API_GetCallerIdentity.html
Severity	Low
Tactics	Discovery
Techniques	T1580
Required data connectors	AWS AWSS3
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_CredentialHijack.yaml
Version	1.0.4
Arm template	32555639-b639-4c2b-afda-c0ae0abefa55.json

KQL

AWSCloudTrail
| where EventName =~ "GetCallerIdentity" and UserIdentityType =~ "AssumedRole"
| 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]), "")
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by SourceIpAddress, EventName, EventTypeName, UserIdentityType, RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityAccountId, UserIdentityPrincipalid,
  UserAgent, UserIdentityUserName, SessionMfaAuthenticated, AWSRegion, EventSource, AdditionalEventData, ResponseElements
| extend timestamp = StartTime
| sort by EndTime desc nulls last

YAML

id: 32555639-b639-4c2b-afda-c0ae0abefa55
severity: Low
queryPeriod: 1d
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon%20Web%20Services/Analytic%20Rules/AWS_CredentialHijack.yaml
version: 1.0.4
kind: Scheduled
requiredDataConnectors:
- dataTypes:
  - AWSCloudTrail
  connectorId: AWS
- dataTypes:
  - AWSCloudTrail
  connectorId: AWSS3
triggerThreshold: 0
status: Available
relevantTechniques:
- T1580
entityMappings:
- fieldMappings:
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  - columnName: RecipientAccountId
    identifier: CloudAppAccountId
  entityType: Account
- fieldMappings:
  - columnName: SourceIpAddress
    identifier: Address
  entityType: IP
customDetails:
  EventType: EventTypeName
  AWSRegion: AWSRegion
  EventName: EventName
  EventSource: EventSource
name: AWSCloudTrail - Monitor AWS Credential abuse or hijacking
query: |
  AWSCloudTrail
  | where EventName =~ "GetCallerIdentity" and UserIdentityType =~ "AssumedRole"
  | 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]), "")
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by SourceIpAddress, EventName, EventTypeName, UserIdentityType, RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityAccountId, UserIdentityPrincipalid,
    UserAgent, UserIdentityUserName, SessionMfaAuthenticated, AWSRegion, EventSource, AdditionalEventData, ResponseElements
  | extend timestamp = StartTime
  | sort by EndTime desc nulls last
queryFrequency: 1d
alertDetailsOverride:
  alertDisplayNameFormat: AWS credential hijack indicator from {{AccountName}}
  alertDescriptionFormat: GetCallerIdentity invoked by {{AccountName}} from {{SourceIpAddress}} in {{AWSRegion}}.
description: |
  Identifies AWS STS `GetCallerIdentity` calls made by assumed-role sessions.
  An attacker who has assumed the role of a legitimate account can call the GetCallerIdentity function to determine what account they are using.
  A legitimate user using legitimate credentials would not need to call GetCallerIdentity since they should already know what account they are using.
  More Information: https://duo.com/decipher/trailblazer-hunts-compromised-credentials-in-aws 
  AWS STS GetCallerIdentity API: https://docs.aws.amazon.com/STS/latest/APIReference/API_GetCallerIdentity.html
tactics:
- Discovery
triggerOperator: gt

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/32555639-b639-4c2b-afda-c0ae0abefa55')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/32555639-b639-4c2b-afda-c0ae0abefa55')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "GetCallerIdentity invoked by {{AccountName}} from {{SourceIpAddress}} in {{AWSRegion}}.",
          "alertDisplayNameFormat": "AWS credential hijack indicator from {{AccountName}}"
        },
        "alertRuleTemplateName": "32555639-b639-4c2b-afda-c0ae0abefa55",
        "customDetails": {
          "AWSRegion": "AWSRegion",
          "EventName": "EventName",
          "EventSource": "EventSource",
          "EventType": "EventTypeName"
        },
        "description": "Identifies AWS STS `GetCallerIdentity` calls made by assumed-role sessions.\nAn attacker who has assumed the role of a legitimate account can call the GetCallerIdentity function to determine what account they are using.\nA legitimate user using legitimate credentials would not need to call GetCallerIdentity since they should already know what account they are using.\nMore Information: https://duo.com/decipher/trailblazer-hunts-compromised-credentials-in-aws \nAWS STS GetCallerIdentity API: https://docs.aws.amazon.com/STS/latest/APIReference/API_GetCallerIdentity.html\n",
        "displayName": "AWSCloudTrail - Monitor AWS Credential abuse or hijacking",
        "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_CredentialHijack.yaml",
        "query": "AWSCloudTrail\n| where EventName =~ \"GetCallerIdentity\" and UserIdentityType =~ \"AssumedRole\"\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| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by SourceIpAddress, EventName, EventTypeName, UserIdentityType, RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityAccountId, UserIdentityPrincipalid,\n  UserAgent, UserIdentityUserName, SessionMfaAuthenticated, AWSRegion, EventSource, AdditionalEventData, ResponseElements\n| extend timestamp = StartTime\n| sort by EndTime desc nulls last\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Low",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Discovery"
        ],
        "techniques": [
          "T1580"
        ],
        "templateVersion": "1.0.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}