GCP Audit Logs - Detect Bulk VM Snapshot Deletion

Requête originale, sans modification.

// Update these thresholds if noisy in your environment
let SnapshotDeletionThreshold = 10;
let TimeWindow = 1m;
GCPAuditLogs
| where ServiceName == "compute.googleapis.com"
| where MethodName has "compute.snapshots.delete"
| where GCPResourceType == "gce_snapshot" and Severity == "NOTICE"
| extend 
    AuthzInfoJson = parse_json(AuthorizationInfo),
    RequestMetadataJson = parse_json(RequestMetadata),
    ResponseJson = parse_json(Response)
| extend PermissionType = tostring(AuthzInfoJson[0].permissionType)
| where PermissionType == "ADMIN_WRITE"
| extend 
    CallerIpAddress = tostring(RequestMetadataJson.callerIp),
    UserAgent = tostring(RequestMetadataJson.callerSuppliedUserAgent),
    SnapshotName = extract(@"snapshots/([^/]+)", 1, GCPResourceName),
    OperationType = tostring(ResponseJson.operationType),
    OperationId = tostring(ResponseJson.id)
| summarize 
    SnapshotCount = count(),
    SnapshotList = make_set(SnapshotName, 100),
    FirstDeletion = min(TimeGenerated),
    LastDeletion = max(TimeGenerated),
    OperationIds = make_set(OperationId, 100),
    CallerIPs = make_set(CallerIpAddress, 10)
    by PrincipalEmail, ProjectId, UserAgent
| where SnapshotCount >= SnapshotDeletionThreshold
| extend DeletionTimeSpan = LastDeletion - FirstDeletion
| where DeletionTimeSpan <= TimeWindow
| extend 
    AccountName = tostring(split(PrincipalEmail, "@")[0]), 
    AccountUPNSuffix = tostring(split(PrincipalEmail, "@")[1])
| project 
    TimeGenerated = FirstDeletion,
    PrincipalEmail,
    ProjectId,
    SnapshotCount,
    SnapshotList,
    FirstDeletion,
    LastDeletion,
    DeletionTimeSpan,
    CallerIPs,
    UserAgent,
    OperationIds,
    AccountName,
    AccountUPNSuffix