Service Principal Name (SPN) Assigned to User Account

Severity: medium
Time window: 1h
Group by: AttributeValue, Computer, ObjectDN, SubjectAccount, SubjectDomainName, SubjectUserName, SubjectUserSid
Author: Vasileios Paschalidis
Source: github.com/Azure/Azure-Sentinel

This query identifies whether an Active Directory user object was assigned a service principal name which could indicate that an adversary is preparing for performing Kerberoasting. This query checks for event id 5136, that the Object Class field is "user" and the LDAP Display Name is "servicePrincipalName". Ref: https://thevivi.net/assets/docs/2019/theVIVI-AD-Security-Workshop_AfricaHackon2019.pdf

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1134` Access Token Manipulation

Event coverage

Provider	Event	Title
Security-Auditing	Event ID 5136	A directory service object was modified.

Rule body kusto

id: 875d0eb1-883a-4191-bd0e-dbfdeb95a464
name: Service Principal Name (SPN) Assigned to User Account
description: |
  'This query identifies whether an Active Directory user object was assigned a service principal name which could indicate that an adversary is preparing for performing Kerberoasting. 
  This query checks for event id 5136, that the Object Class field is "user" and the LDAP Display Name is "servicePrincipalName".
  Ref: https://thevivi.net/assets/docs/2019/theVIVI-AD-Security-Workshop_AfricaHackon2019.pdf'
severity: Medium
requiredDataConnectors:
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - PrivilegeEscalation
relevantTechniques:
  - T1134
query: |
    SecurityEvent
    | where EventID == 5136 
    | parse EventData with * 'AttributeLDAPDisplayName">' AttributeLDAPDisplayName "<" *
    | parse EventData with * 'ObjectClass">' ObjectClass "<" *
    | where AttributeLDAPDisplayName == "servicePrincipalName" and  ObjectClass == "user"
    | parse EventData with * 'ObjectDN">' ObjectDN "<" *
    | parse EventData with * 'AttributeValue">' AttributeValue "<" *
    | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by Computer, SubjectAccount, ObjectDN, AttributeValue, SubjectUserName, SubjectDomainName, SubjectUserSid
    | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
    | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
    | project-away DomainIndex
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: SubjectAccount
      - identifier: Name
        columnName: SubjectUserName
      - identifier: NTDomain
        columnName: SubjectDomainName
  - entityType: Account
    fieldMappings:
      - identifier: Sid
        columnName: SubjectUserSid
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Computer
      - identifier: HostName
        columnName: HostName
      - identifier: NTDomain
        columnName: HostNameDomain
version: 1.0.4
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Vasileios Paschalidis
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Identity" ]

Stages and Predicates

Stage 1: `source`

SecurityEvent

Stage 2: `where`

| where EventID == 5136

Stage 3: `parse`

| parse EventData with * 'AttributeLDAPDisplayName">' AttributeLDAPDisplayName "<" *

Stage 4: `parse`

| parse EventData with * 'ObjectClass">' ObjectClass "<" *

Stage 5: `where`

| where AttributeLDAPDisplayName == "servicePrincipalName" and  ObjectClass == "user"

Stage 6: `parse`

| parse EventData with * 'ObjectDN">' ObjectDN "<" *

Stage 7: `parse`

| parse EventData with * 'AttributeValue">' AttributeValue "<" *

Stage 8: `summarize`

| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by Computer, SubjectAccount, ObjectDN, AttributeValue, SubjectUserName, SubjectDomainName, SubjectUserSid

Stage 9: `extend`

| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))

Stage 10: `extend`

| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)

HostNameDomain =

ifDomainIndex != -1substring(Computer, (DomainIndex + 1))

elseComputer

Stage 11: `project-away`

| project-away DomainIndex

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
`AttributeLDAPDisplayName`	eq	`servicePrincipalName` transforms: `cased` corpus 9 (sigma 4, splunk 3, elastic 1, kusto 1)
`EventID`	eq	`5136` transforms: `cased` corpus 30 (splunk 24, kusto 5, elastic 1)
`ObjectClass`	eq	`user` transforms: `cased` corpus 6 (sigma 2, splunk 2, elastic 1, kusto 1)

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
`AttributeValue`	`summarize`
`Computer`	`summarize`
`EndTime`	`summarize`
`ObjectDN`	`summarize`
`StartTime`	`summarize`
`SubjectAccount`	`summarize`
`SubjectDomainName`	`summarize`
`SubjectUserName`	`summarize`
`SubjectUserSid`	`summarize`
`HostName`	`extend`
`HostNameDomain`	`extend`

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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)

Service Principal Name (SPN) Assigned to User Account

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Stage 1: `source`

Stage 2: `where`

Stage 3: `parse`

Stage 4: `parse`

Stage 5: `where`

Stage 6: `parse`

Stage 7: `parse`

Stage 8: `summarize`

Stage 9: `extend`

Stage 10: `extend`

Stage 11: `project-away`

Indicators

Output fields

Keyboard shortcuts

Search operators

Service Principal Name (SPN) Assigned to User Account

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Stage 1: source

Stage 2: where

Stage 3: parse

Stage 4: parse

Stage 5: where

Stage 6: parse

Stage 7: parse

Stage 8: summarize

Stage 9: extend

Stage 10: extend

Stage 11: project-away

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `parse`

Stage 4: `parse`

Stage 5: `where`

Stage 6: `parse`

Stage 7: `parse`

Stage 8: `summarize`

Stage 9: `extend`

Stage 10: `extend`

Stage 11: `project-away`