Password spray attack against Microsoft Entra ID Seamless SSO

Status: available
Severity: medium
Time window: 1h
Group by: IPAddress, ResultType, Type
Source: github.com/Azure/Azure-Sentinel

'This query detects when there is a spike in Microsoft Entra ID Seamless SSO errors. They may not be caused by a Password Spray attack, but the cause of the errors might need to be investigated. Microsoft Entra ID only logs the requests that matched existing accounts, thus there might have been unlogged requests for non-existing accounts.'

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1110` Brute Force

Rule body kusto

id: fb7ca1c9-e14c-40a3-856e-28f3c14ea1ba
name: Password spray attack against Microsoft Entra ID Seamless SSO
description: |
  'This query detects when there is a spike in Microsoft Entra ID Seamless SSO errors. They may not be caused by a Password Spray attack, but the cause of the errors might need to be investigated.
  Microsoft Entra ID only logs the requests that matched existing accounts, thus there might have been unlogged requests for non-existing accounts.'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AADNonInteractiveUserSignInLogs
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
status: Available
tactics:
  - CredentialAccess
relevantTechniques:
  - T1110
query: |
  let account_threshold = 5;
  AADNonInteractiveUserSignInLogs
  //| where ResultType == "81016"
  | where ResultType startswith "81"
  | summarize DistinctAccounts = dcount(UserPrincipalName), DistinctAddresses = make_set(IPAddress,100) by ResultType
  | where DistinctAccounts > account_threshold
  | mv-expand IPAddress = DistinctAddresses
  | extend IPAddress = tostring(IPAddress)
  | join kind=leftouter (union isfuzzy=true SigninLogs, AADNonInteractiveUserSignInLogs) on IPAddress
  | summarize
      StartTime = min(TimeGenerated),
      EndTime = max(TimeGenerated),
      UserPrincipalName = make_set(UserPrincipalName,100),
      UserAgent = make_set(UserAgent,100),
      ResultDescription = take_any(ResultDescription),
      ResultSignature = take_any(ResultSignature)
      by IPAddress, Type, ResultType
  | project Type, StartTime, EndTime, IPAddress, ResultType, ResultDescription, ResultSignature, UserPrincipalName, UserAgent = iff(array_length(UserAgent) == 1, UserAgent[0], UserAgent)
  | extend Name = tostring(split(UserPrincipalName[0],'@',0)[0]), UPNSuffix = tostring(split(UserPrincipalName[0],'@',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

Parameters

let account_threshold = 5;

Stage 1: `source`

AADNonInteractiveUserSignInLogs

Stage 2: `where`

| where ResultType startswith "81"

Stage 3: `summarize`

| summarize DistinctAccounts = dcount(UserPrincipalName), DistinctAddresses = make_set(IPAddress,100) by ResultType

Threshold: gt 5

Stage 4: `where`

| where DistinctAccounts > account_threshold

Stage 5: `mv-expand`

| mv-expand IPAddress = DistinctAddresses

Stage 6: `extend`

| extend IPAddress = tostring(IPAddress)

Stage 7: `join`

| join kind=leftouter (union isfuzzy=true SigninLogs, AADNonInteractiveUserSignInLogs) on IPAddress

Stage 8: `summarize`

| summarize
    StartTime = min(TimeGenerated),
    EndTime = max(TimeGenerated),
    UserPrincipalName = make_set(UserPrincipalName,100),
    UserAgent = make_set(UserAgent,100),
    ResultDescription = take_any(ResultDescription),
    ResultSignature = take_any(ResultSignature)
    by IPAddress, Type, ResultType

Stage 9: `project`

| project Type, StartTime, EndTime, IPAddress, ResultType, ResultDescription, ResultSignature, UserPrincipalName, UserAgent = iff(array_length(UserAgent) == 1, UserAgent[0], UserAgent)

Stage 10: `extend`

| extend Name = tostring(split(UserPrincipalName[0],'@',0)[0]), UPNSuffix = tostring(split(UserPrincipalName[0],'@',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
`DistinctAccounts`	gt	`5` transforms: `cased`
`ResultType`	starts_with	`81`

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
`EndTime`	`project`
`IPAddress`	`project`
`ResultDescription`	`project`
`ResultSignature`	`project`
`ResultType`	`project`
`StartTime`	`project`
`Type`	`project`
`UserAgent`	`project`
`UserPrincipalName`	`project`
`Name`	`extend`
`UPNSuffix`	`extend`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`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)

Password spray attack against Microsoft Entra ID Seamless SSO

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: `source`

Stage 2: `where`

Stage 3: `summarize`

Stage 4: `where`

Stage 5: `mv-expand`

Stage 6: `extend`

Stage 7: `join`

Stage 8: `summarize`

Stage 9: `project`

Stage 10: `extend`

Indicators

Output fields

Keyboard shortcuts

Search operators

Password spray attack against Microsoft Entra ID Seamless SSO

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: source

Stage 2: where

Stage 3: summarize

Stage 4: where

Stage 5: mv-expand

Stage 6: extend

Stage 7: join

Stage 8: summarize

Stage 9: project

Stage 10: extend

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `summarize`

Stage 4: `where`

Stage 5: `mv-expand`

Stage 6: `extend`

Stage 7: `join`

Stage 8: `summarize`

Stage 9: `project`

Stage 10: `extend`