GitLab - User Impersonation

Status: available
Severity: medium
Time window: 1d
Group by: AuthorName, TargetDetails
Source: github.com/Azure/Azure-Sentinel

'This queries GitLab Audit Logs for user impersonation. A malicious operator or a compromised admin account could leverage the impersonation feature of GitLab to change code or repository settings bypassing usual processes. This hunting queries allows you to track the audit actions done under impersonation.'

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1078` Valid Accounts

Rule body kusto

id: 0f4f16a2-b464-4c10-9a42-993da3e15a40
name: GitLab - User Impersonation
description: |
  'This queries GitLab Audit Logs for user impersonation. A malicious operator or a compromised admin account could leverage the impersonation feature of GitLab to change code or repository settings bypassing usual processes. This hunting queries allows you to track the audit actions done under impersonation.'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: SyslogAma
    dataTypes: 
      - Syslog
queryFrequency: 1h
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Persistence
relevantTechniques:
  - T1078
query: |
  let impersonationStart = (GitLabAudit
  | where CustomMessage == 'Started Impersonation');
  let impersonationStop = (GitLabAudit
  | where CustomMessage == 'Stopped Impersonation');
  impersonationStart
  | join kind=inner impersonationStop on $left.TargetID == $right.TargetID and $left.AuthorID == $right.AuthorID 
  | where EventTime1 > EventTime
  | extend TimeGenerated, AuthorID, AuthorName, TargetID, TargetDetails = TargetDetails, IPStart = IPAddress, IPStop = IPAddress1, ImpStartTime = EventTime, ImpStopTime = EventTime1, EntityName
  | join kind=inner (GitLabAudit | extend ActionTime = EventTime, AuthorName) on $left.TargetDetails == $right.AuthorName 
  | where ImpStartTime < ActionTime and ActionTime > ImpStopTime
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPStart
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPStop
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: EntityName
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: TargetDetails
version: 1.0.2
kind: Scheduled

Stages and Predicates

Let binding: `impersonationStop`

let impersonationStop = (GitLabAudit
| where CustomMessage == 'Stopped Impersonation');

The stages below define let impersonationStart (the rule's main pipeline source).

Stage 1: `source`

GitLabAudit

Stage 2: `where`

| where CustomMessage == 'Started Impersonation'

The stages below run on impersonationStart (the outer pipeline).

Stage 3: `join`

impersonationStart
| join kind=inner impersonationStop on $left.TargetID == $right.TargetID and $left.AuthorID == $right.AuthorID

Stage 4: `where`

| where EventTime1 > EventTime

Stage 5: `extend`

| extend TimeGenerated, AuthorID, AuthorName, TargetID, TargetDetails = TargetDetails, IPStart = IPAddress, IPStop = IPAddress1, ImpStartTime = EventTime, ImpStopTime = EventTime1, EntityName

Stage 6: `join`

| join kind=inner (GitLabAudit | extend ActionTime = EventTime, AuthorName) on $left.TargetDetails == $right.AuthorName

Stage 7: `where`

| where ImpStartTime < ActionTime and ActionTime > ImpStopTime

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
`ActionTime`	gt	`ImpStopTime` transforms: `cased`
`CustomMessage`	eq	`Started Impersonation` transforms: `cased` `Stopped Impersonation` transforms: `cased`
`EventTime1`	gt	`EventTime` transforms: `cased`
`ImpStartTime`	lt	`ActionTime` 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
`AuthorID`	`extend`
`AuthorName`	`extend`
`EntityName`	`extend`
`IPStart`	`extend`
`IPStop`	`extend`
`ImpStartTime`	`extend`
`ImpStopTime`	`extend`
`TargetDetails`	`extend`
`TargetID`	`extend`
`TimeGenerated`	`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)

GitLab - User Impersonation

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Let binding: `impersonationStop`

Stage 1: `source`

Stage 2: `where`

Stage 3: `join`

Stage 4: `where`

Stage 5: `extend`

Stage 6: `join`

Stage 7: `where`

Indicators

Output fields

Keyboard shortcuts

Search operators

GitLab - User Impersonation

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Let binding: impersonationStop

Stage 1: source

Stage 2: where

Stage 3: join

Stage 4: where

Stage 5: extend

Stage 6: join

Stage 7: where

Indicators

Output fields

Let binding: `impersonationStop`

Stage 1: `source`

Stage 2: `where`

Stage 3: `join`

Stage 4: `where`

Stage 5: `extend`

Stage 6: `join`

Stage 7: `where`