MFA Spamming followed by Successful login

Status: available
Severity: high
Time window: 1d
Group by: City, IPAddress, Region, State, UserPrincipalName
Source: github.com/Azure/Azure-Sentinel

'Identifies MFA Spamming followed by Successful logins and by a successful authentication within a given time window. Default Failure count is 10 and 1 successful login with default Time Window is 5 minutes.'

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1110` Brute Force

Rule body kusto

id: a8cc6d5c-4e7e-4b48-b4ac-d8a116c62a8b
name: MFA Spamming followed by Successful login
description: |
  'Identifies MFA Spamming followed by Successful logins and by a successful authentication within a given time window.
  Default Failure count is 10 and 1 successful login with default Time Window is 5 minutes.'
severity: High
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - SigninLogs
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
status: Available
tactics:
  - CredentialAccess
relevantTechniques:
  - T1110
query: |
  // 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])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: UserPrincipalName
      - identifier: Name
        columnName: Name
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPAddress
version: 1.0.4
kind: Scheduled

Stages and Predicates

Stage 1: `source`

SigninLogs

Stage 2: `where`

| where ingestion_time() > ago(1d)

Stage 3: `where`

| where AuthenticationRequirement == "multiFactorAuthentication"

Stage 4: `extend`

| extend DeviceDetail = todynamic(DeviceDetail), LocationDetails = todynamic(LocationDetails)

Stage 5: `extend`

| extend
      OS = tostring(DeviceDetail.operatingSystem),
      Browser = tostring(DeviceDetail.browser),
      State = tostring(LocationDetails.state),
      City = tostring(LocationDetails.city),
      Region = tostring(LocationDetails.countryOrRegion)

Stage 6: `mv-expand`

| mv-expand todynamic(AuthenticationDetails)

Stage 7: `extend`

| extend AuthResult = tostring(parse_json(AuthenticationDetails).authenticationStepResultDetail)

Stage 8: `summarize`

| 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

Threshold: gt 10

Stage 9: `extend`

| extend AuthenticationWindow = (EndTime - StartTime)

Stage 10: `where`

| where FailedAttempts > 10 and AuthenticationWindow <= 5m and SuccessfulAttempts >= 1

Stage 11: `extend`

| extend Name = tostring(split(UserPrincipalName, '@', 0)[0]), UPNSuffix = tostring(split(UserPrincipalName, '@', 1)[0])

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`AuthenticationRequirement`	eq	`multiFactorAuthentication` transforms: `cased`
`AuthenticationWindow`	le	`5m` transforms: `cased`
`FailedAttempts`	gt	`10` transforms: `cased`
`SuccessfulAttempts`	ge	`1` transforms: `cased`

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`City`	`summarize`
`EndTime`	`summarize`
`FailedAttempts`	`summarize`
`IPAddress`	`summarize`
`InvolvedBrowser`	`summarize`
`InvolvedOS`	`summarize`
`Region`	`summarize`
`StartTime`	`summarize`
`State`	`summarize`
`SuccessfulAttempts`	`summarize`
`UserPrincipalName`	`summarize`
`AuthenticationWindow`	`extend`
`Name`	`extend`
`UPNSuffix`	`extend`

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`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
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`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

MFA Spamming followed by Successful login

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `extend`

Stage 6: `mv-expand`

Stage 7: `extend`

Stage 8: `summarize`

Stage 9: `extend`

Stage 10: `where`

Stage 11: `extend`

Indicators

Output fields

Keyboard shortcuts

Search operators

MFA Spamming followed by Successful login

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: extend

Stage 5: extend

Stage 6: mv-expand

Stage 7: extend

Stage 8: summarize

Stage 9: extend

Stage 10: where

Stage 11: extend

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `extend`

Stage 6: `mv-expand`

Stage 7: `extend`

Stage 8: `summarize`

Stage 9: `extend`

Stage 10: `where`

Stage 11: `extend`