MFA Spamming followed by Successful login

Original query, unchanged.

// Filter for sign-in logs ingested within the last day
SigninLogs
| where ingestion_time() > ago(1d)
// Filter for records with AuthenticationRequirement set to multiFactorAuthentication
| where AuthenticationRequirement == "multiFactorAuthentication"
// Extract information from dynamic columns DeviceDetail and LocationDetails
| extend DeviceDetail = todynamic(DeviceDetail), LocationDetails = todynamic(LocationDetails)
// Extract specific attributes from DeviceDetail and LocationDetails
| extend
      OS = tostring(DeviceDetail.operatingSystem),
      Browser = tostring(DeviceDetail.browser),
      State = tostring(LocationDetails.state),
      City = tostring(LocationDetails.city),
      Region = tostring(LocationDetails.countryOrRegion)
// Expand multi-value property AuthenticationDetails into separate records
| mv-expand todynamic(AuthenticationDetails)
// Parse AuthResult from JSON in AuthenticationDetails and convert to string
| extend AuthResult = tostring(parse_json(AuthenticationDetails).authenticationStepResultDetail)
// Summarize data by aggregating statistics for each user, IP, and AuthResult
| summarize FailedAttempts = countif(AuthResult == "MFA denied; user declined the authentication" or AuthResult == "MFA denied; user did not respond to mobile app notification"), SuccessfulAttempts = countif(AuthResult == "MFA successfully completed"), InvolvedOS = make_set(OS, 5), InvolvedBrowser = make_set(Browser), StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserPrincipalName, IPAddress, State, City, Region
// Calculate AuthenticationWindow by finding time difference between start and end times
| extend AuthenticationWindow = (EndTime - StartTime)
// Filter for records with more than 10 failed attempts in 5-minute window and at least 1 successful attempt
| where FailedAttempts > 10 and AuthenticationWindow <= 5m and SuccessfulAttempts >= 1
// Extract user's name and UPN suffix using split function
| extend Name = tostring(split(UserPrincipalName, '@', 0)[0]), UPNSuffix = tostring(split(UserPrincipalName, '@', 1)[0])