Suspicious VM Instance Creation Activity Detected

Requête originale, sans modification.

// Filter alerts from specific Microsoft security products with medium and high severity
SecurityAlert 
| where ProductName in ("Microsoft 365 Defender", "Azure Active Directory", "Microsoft Defender Advanced Threat Protection", "Microsoft Cloud App Security", "Azure Active Directory Identity Protection", "Microsoft Defender ATP")
| where AlertSeverity has_any ("Medium", "High")
// Parse JSON entities and extend AlertTimeGenerated
| extend Entities = parse_json(Entities), AlertTimeGenerated=TimeGenerated
// Extract and process IP entities
| mv-apply Entity = Entities on 
    ( 
    where Entity.Type == 'ip' 
    | extend EntityIp = tostring(Entity.Address) 
    ) 
// Extract and process account entities
| mv-apply Entity = Entities on 
    ( 
    where Entity.Type == 'account' 
    | extend AccountObjectId = tostring(Entity.AadUserId)
    )
// Filter out records with empty EntityIp
| where isnotempty(EntityIp)
// Summarize data and create sets of entities and system alert IDs
| summarize Entitys=make_set(Entity), SystemAlertIds=make_set(SystemAlertId)
    by 
    AlertName,
    ProductName,
    AlertSeverity,
    EntityIp,
    Tactics,
    Techniques,
    ProviderName,
    AlertTime= bin(AlertTimeGenerated, 1d),
    AccountObjectId
// Join with GCPAuditLogs for VM instance creation
| join kind=inner (
    GCPAuditLogs
    | where ServiceName == "compute.googleapis.com" and MethodName endswith "instances.insert"
    | extend
        GCPUserUPN= tostring(parse_json(AuthenticationInfo).principalEmail),
        GCPUserIp = tostring(parse_json(RequestMetadata).callerIp),
        GCPUserUA= tostring(parse_json(RequestMetadata).callerSuppliedUserAgent),
        VMStatus =  tostring(parse_json(Response).status),
        VMOperation=tostring(parse_json(Response).operationType),
        VMName= tostring(parse_json(Request).name),
        VMType = tostring(split(parse_json(Request).machineType, "/")[-1])
    | where GCPUserUPN !has "gserviceaccount.com"
    | where VMOperation == "insert" and isnotempty(GCPUserIp) and GCPUserIp != "private"
    | project
        GCPOperationTime=TimeGenerated,
        VMName,
        VMStatus,
        MethodName,
        GCPUserUPN,
        ProjectId,
        GCPUserIp,
        GCPUserUA,
        VMOperation,
        VMType
    )
    on $left.EntityIp == $right.GCPUserIp 
// Join with IdentityInfo to enrich user identity details
| join kind=inner (IdentityInfo 
    | distinct AccountObjectId, AccountUPN, JobTitle
    )
    on AccountObjectId 
// Calculate the time difference between the alert and VM creation for further analysis
| extend TimeDiff= datetime_diff('day', AlertTime, GCPOperationTime),Name = split(GCPUserUPN, "@")[0], UPNSuffix = split(GCPUserUPN, "@")[1]