AWSCloudTrail - Privilege escalation with FullAccess managed policy

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Id	afb4191b-a142-4065-a0da-f721ee3d006c
Rulename	AWSCloudTrail - Privilege escalation with FullAccess managed policy
Description	Detects successful attachment of AWS managed policies containing FullAccess permissions to users, roles, or groups, excluding admin-named policies. This action can rapidly expand privilege scope and should be reviewed as potential cloud privilege escalation.
Severity	Medium
Tactics	PrivilegeEscalation Persistence
Techniques	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 Web Services/Analytic Rules/AWS_PrivilegeEscalationFullAccessManagedPolicy.yaml
Version	1.0.2
Arm template	afb4191b-a142-4065-a0da-f721ee3d006c.json

KQL

AWSCloudTrail
| where  EventName in ("AttachUserPolicy","AttachRolePolicy","AttachGroupPolicy") and isempty(ErrorCode) and isempty(ErrorMessage)
| where tostring(parse_json(RequestParameters).policyArn) has "FullAccess" and tostring(parse_json(RequestParameters).policyArn) !has "Admin"
| 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]), "")
| project TimeGenerated, EventName, EventTypeName, UserIdentityAccountId, UserIdentityPrincipalid, UserAgent, RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityUserName, SessionMfaAuthenticated, SourceIpAddress, AWSRegion, EventSource, AdditionalEventData, RequestParameters, UserIdentityArn, ResponseElements

YAML

id: afb4191b-a142-4065-a0da-f721ee3d006c
tactics:
- PrivilegeEscalation
- Persistence
status: Available
triggerThreshold: 0
query: |
  AWSCloudTrail
  | where  EventName in ("AttachUserPolicy","AttachRolePolicy","AttachGroupPolicy") and isempty(ErrorCode) and isempty(ErrorMessage)
  | where tostring(parse_json(RequestParameters).policyArn) has "FullAccess" and tostring(parse_json(RequestParameters).policyArn) !has "Admin"
  | 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]), "")
  | project TimeGenerated, EventName, EventTypeName, UserIdentityAccountId, UserIdentityPrincipalid, UserAgent, RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityUserName, SessionMfaAuthenticated, SourceIpAddress, AWSRegion, EventSource, AdditionalEventData, RequestParameters, UserIdentityArn, ResponseElements  
kind: Scheduled
description: |
  Detects successful attachment of AWS managed policies containing FullAccess permissions to users, roles, or
  groups, excluding admin-named policies. This action can rapidly expand privilege scope and should be reviewed
  as potential cloud privilege escalation.  
alertDetailsOverride:
  alertDescriptionFormat: Detected {{EventName}} from {{SourceIpAddress}} attaching FullAccess managed policy in account {{RecipientAccountId}}.
  alertDisplayNameFormat: AWS FullAccess managed policy attachment by {{AccountName}}
name: AWSCloudTrail - Privilege escalation with FullAccess managed policy
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_PrivilegeEscalationFullAccessManagedPolicy.yaml
relevantTechniques:
- T1098.003
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  - columnName: RecipientAccountId
    identifier: CloudAppAccountId
- entityType: IP
  fieldMappings:
  - columnName: SourceIpAddress
    identifier: Address
severity: Medium
queryFrequency: 1d
version: 1.0.2
customDetails:
  EventName: EventName
  EventSource: EventSource
  AWSRegion: AWSRegion
  UserIdentityArn: UserIdentityArn
requiredDataConnectors:
- connectorId: AWS
  dataTypes:
  - AWSCloudTrail
triggerOperator: gt
queryPeriod: 1d

ARM