AWSCloudTrail - Policy version set to default

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Id	874a1762-3fd7-4489-b411-6d4a9e9e8a59
Rulename	AWSCloudTrail - Policy version set to default
Description	Detects SetDefaultPolicyVersion activity that makes a different IAM policy version active. Attackers can use this to activate previously created permissive versions and escalate access.
Severity	Medium
Tactics	PrivilegeEscalation
Techniques	T1098.003
Required data connectors	AWS
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_SetDefaulyPolicyVersion.yaml
Version	1.0.2
Arm template	874a1762-3fd7-4489-b411-6d4a9e9e8a59.json

KQL

AWSCloudTrail
| where EventName == "SetDefaultPolicyVersion" 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]), "")

YAML

name: AWSCloudTrail - Policy version set to default
requiredDataConnectors:
- dataTypes:
  - AWSCloudTrail
  connectorId: AWS
queryPeriod: 1h
relevantTechniques:
- T1098.003
tactics:
- PrivilegeEscalation
alertDetailsOverride:
  alertDescriptionFormat: Detected SetDefaultPolicyVersion from {{SourceIpAddress}} in account {{RecipientAccountId}}.
  alertDisplayNameFormat: AWS IAM default policy version changed by {{AccountName}}
id: 874a1762-3fd7-4489-b411-6d4a9e9e8a59
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_SetDefaulyPolicyVersion.yaml
kind: Scheduled
query: |
  AWSCloudTrail
  | where EventName == "SetDefaultPolicyVersion" 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]), "")  
version: 1.0.2
entityMappings:
- fieldMappings:
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: AccountUPNSuffix
  - identifier: CloudAppAccountId
    columnName: RecipientAccountId
  entityType: Account
- fieldMappings:
  - identifier: Address
    columnName: SourceIpAddress
  entityType: IP
triggerOperator: gt
description: |
  Detects SetDefaultPolicyVersion activity that makes a different IAM policy version active.
  Attackers can use this to activate previously created permissive versions and escalate access.  
triggerThreshold: 0
queryFrequency: 1h
status: Available
severity: Medium
customDetails:
  EventName: EventName
  UserIdentityArn: UserIdentityArn
  AWSRegion: AWSRegion
  EventSource: EventSource

ARM