Microsoft365 Brute Force Login by User

Severity: medium
Log types: Microsoft365.Audit.AzureActiveDirectory
Reference: https://learn.microsoft.com/en-us/microsoft-365/troubleshoot/authentication/access-denied-when-connect-to-office-365
Source: github.com/panther-labs/panther-analysis

A Microsoft365 user was denied login access several times

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1110` Brute Force

Rule body yaml

AnalysisType: rule
Description: A Microsoft365 user was denied login access several times
DisplayName: "Microsoft365 Brute Force Login by User"
Enabled: true
Filename: microsoft365_brute_force_login_by_user.py
Reports:
  MITRE ATT&CK:
    - TA0006:T1110 # Credential Access - Brute Force
Runbook: Analyze the IP they came from and actions taken before/after.
Reference: https://learn.microsoft.com/en-us/microsoft-365/troubleshoot/authentication/access-denied-when-connect-to-office-365
Severity: Medium
Tests:
  - ExpectedResult: true
    Log:
      Actor:
        - ID: 012345-abcde-543-xyz
          Type: 0
        - ID: sample.user@yourorg.onmicrosoft.com
          Type: 5
      ActorContextId: 123-abc-xyz-567
      ActorIpAddress: 1.2.3.4
      ApplicationId: 123-abc-sfa-321
      AzureActiveDirectoryEventType: 1
      ClientIP: 1.2.3.4
      CreationTime: "2022-12-12 15:57:57"
      ExtendedProperties:
        - Name: ResultStatusDetail
          Value: Success
        - Name: UserAgent
          Value: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Safari/537.36
        - Name: UserAuthenticationMethod
          Value: "1"
        - Name: RequestType
          Value: Login:login
      Id: abc-def-123
      InterSystemsId: 987-432-123
      IntraSystemId: aaa-bbb-ccc
      LogonError: InvalidUserNameOrPassword
      ObjectId: aa-11-22-bb
      Operation: UserLoginFailed
      OrganizationId: 11-aa-22-bb
      RecordType: 15
      ResultStatus: Success
      SupportTicketId: ""
      Target:
        - ID: 11-22-33
          Type: 0
      TargetContextId: 11-22-33-44
      UserId: sample.user@yourorg.onmicrosoft.com
      UserKey: 012345-abcde-543-xyz
      UserType: 0
      Workload: AzureActiveDirectory
    Name: Failed Login event
  - ExpectedResult: false
    Log:
      Actor:
        - ID: 012345-abcde-543-xyz
          Type: 0
        - ID: sample.user@yourorg.onmicrosoft.com
          Type: 5
      ActorContextId: 123-abc-xyz-567
      ActorIpAddress: 1.2.3.4
      ApplicationId: 123-abc-sfa-321
      AzureActiveDirectoryEventType: 1
      ClientIP: 1.2.3.4
      CreationTime: "2022-12-12 15:57:57"
      ExtendedProperties:
        - Name: ResultStatusDetail
          Value: Success
        - Name: UserAgent
          Value: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Safari/537.36
        - Name: RequestType
          Value: Login:reprocess
      Id: abc-def-123
      InterSystemsId: 987-432-123
      IntraSystemId: aaa-bbb-ccc
      ObjectId: aa-11-22-bb
      Operation: UserLoggedIn
      OrganizationId: 11-aa-22-bb
      RecordType: 15
      ResultStatus: Success
      SupportTicketId: ""
      Target:
        - ID: 11-22-33
          Type: 0
      TargetContextId: 11-22-33-44
      UserId: sample.user@yourorg.onmicrosoft.com
      UserKey: 012345-abcde-543-xyz
      UserType: 0
    Name: Login Event
DedupPeriodMinutes: 60
LogTypes:
  - Microsoft365.Audit.AzureActiveDirectory
RuleID: "Microsoft365.Brute.Force.Login.by.User"
Threshold: 10

Detection logic

Condition

Operation eq "UserLoginFailed"

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
`Operation`	eq	`UserLoginFailed`

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
`operation`	`Operation`
`organization_id`	`OrganizationId`
`client_ip`	`ClientIp`
`extended_properties`	`ExtendedProperties`
`modified_properties`	`ModifiedProperties`
`application`	`Application`
`actor`	`Actor`
`UserId`

`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)