Azure DevOps Agent Pool Created Then Deleted

Status: available
Severity: high
Time window: 14d
Source: github.com/Azure/Azure-Sentinel

'As well as adding build agents to an existing pool to execute malicious activity within a pipeline, an attacker could create a complete new agent pool and use this for execution. Azure DevOps allows for the creation of agent pools with Azure hosted infrastructure or self-hosted infrastructure. Given the additional customizability of self-hosted agents this detection focuses on the creation of new self-hosted pools. To further reduce false positive rates the detection looks for pools created and deleted relatively quickly (within 7 days by default), as an attacker is likely to remove a malicious pool once used in order to reduce/remove evidence of their activity.'

MITRE ATT&CK coverage

Tactic	Techniques
Defense Impairment	`T1578.002` Modify Cloud Compute Infrastructure: Create Cloud Instance

Rule body kusto

id: acfdee3f-b794-404a-aeba-ef6a1fa08ad1
name: Azure DevOps Agent Pool Created Then Deleted
description: |
  'As well as adding build agents to an existing pool to execute malicious activity within a pipeline, an attacker could create a complete new agent pool and use this for execution.
  Azure DevOps allows for the creation of agent pools with Azure hosted infrastructure or self-hosted infrastructure. Given the additional customizability of self-hosted agents this   detection focuses on the creation of new self-hosted pools.
  To further reduce false positive rates the detection looks for pools created and deleted relatively quickly (within 7 days by default), as an attacker is likely to remove a malicious pool once used in order to reduce/remove evidence of their activity.'
severity: High
status: Available
requiredDataConnectors: []
queryFrequency: 7d
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - DefenseEvasion
relevantTechniques:
  - T1578.002
query: |
  let lookback = 14d;
  let timewindow = 7d;
  ADOAuditLogs
  | where TimeGenerated > ago(lookback)
  | where OperationName =~ "Library.AgentPoolCreated"
  | extend AgentCloudId = tostring(Data.AgentCloudId)
  | extend PoolType = iif(isnotempty(AgentCloudId), "Azure VMs", "Self Hosted")
  // Comment this line out to include cloud pools as well
  | where PoolType == "Self Hosted"
  | extend AgentPoolName = tostring(Data.AgentPoolName)
  | extend AgentPoolId = tostring(Data.AgentPoolId)
  | extend IsHosted = tostring(Data.IsHosted)
  | extend IsLegacy = tostring(Data.IsLegacy)
  | extend timekey = bin(TimeGenerated, timewindow)
  // Join only with pools deleted in the same window
  | join (ADOAuditLogs
  | where TimeGenerated > ago(lookback)
  | where OperationName =~ "Library.AgentPoolDeleted"
  | extend AgentPoolName = tostring(Data.AgentPoolName)
  | extend AgentPoolId = tostring(Data.AgentPoolId)
  | extend timekey = bin(TimeGenerated, timewindow)) on AgentPoolId, timekey
  | project-reorder TimeGenerated, ActorUPN, UserAgent, IpAddress, AuthenticationMechanism, OperationName, AgentPoolName, IsHosted, IsLegacy, Data
  | extend timestamp = TimeGenerated
  | extend AccountName = tostring(split(ActorUPN, "@")[0]), AccountUPNSuffix = tostring(split(ActorUPN, "@")[1])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: ActorUPN    
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IpAddress
version: 1.0.5
kind: Scheduled

Stages and Predicates

Parameters

let lookback = 14d;
let timewindow = 7d;

Stage 1: `source`

ADOAuditLogs

Stage 2: `where`

| where TimeGenerated > ago(lookback)

Stage 3: `where`

| where OperationName =~ "Library.AgentPoolCreated"

Stage 4: `extend`

| extend AgentCloudId = tostring(Data.AgentCloudId)

Stage 5: `extend`

| extend PoolType = iif(isnotempty(AgentCloudId), "Azure VMs", "Self Hosted")

Stage 6: `where`

| where PoolType == "Self Hosted"

Stage 7: `extend` (5 consecutive steps)

| extend AgentPoolName = tostring(Data.AgentPoolName)
| extend AgentPoolId = tostring(Data.AgentPoolId)
| extend IsHosted = tostring(Data.IsHosted)
| extend IsLegacy = tostring(Data.IsLegacy)
| extend timekey = bin(TimeGenerated, timewindow)

Stage 8: `join`

| join (ADOAuditLogs
| where TimeGenerated > ago(lookback)
| where OperationName =~ "Library.AgentPoolDeleted"
| extend AgentPoolName = tostring(Data.AgentPoolName)
| extend AgentPoolId = tostring(Data.AgentPoolId)
| extend timekey = bin(TimeGenerated, timewindow)) on AgentPoolId, timekey

Stage 9: `project-reorder`

| project-reorder TimeGenerated, ActorUPN, UserAgent, IpAddress, AuthenticationMechanism, OperationName, AgentPoolName, IsHosted, IsLegacy, Data

Stage 10: `extend`

| extend timestamp = TimeGenerated

Stage 11: `extend`

| extend AccountName = tostring(split(ActorUPN, "@")[0]), AccountUPNSuffix = tostring(split(ActorUPN, "@")[1])

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
`OperationName`	eq	`Library.AgentPoolCreated` `Library.AgentPoolDeleted`
`PoolType`	eq	`Self Hosted` 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
`AgentCloudId`	`extend`
`PoolType`	`extend`
`AgentPoolName`	`extend`
`AgentPoolId`	`extend`
`IsHosted`	`extend`
`IsLegacy`	`extend`
`timekey`	`extend`
`timestamp`	`extend`
`AccountName`	`extend`
`AccountUPNSuffix`	`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)

Azure DevOps Agent Pool Created Then Deleted

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `extend`

Stage 6: `where`

Stage 7: `extend` (5 consecutive steps)

Stage 8: `join`

Stage 9: `project-reorder`

Stage 10: `extend`

Stage 11: `extend`

Indicators

Output fields

Keyboard shortcuts

Search operators

Azure DevOps Agent Pool Created Then Deleted

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: extend

Stage 5: extend

Stage 6: where

Stage 7: extend (5 consecutive steps)

Stage 8: join

Stage 9: project-reorder

Stage 10: extend

Stage 11: extend

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `extend`

Stage 6: `where`

Stage 7: `extend` (5 consecutive steps)

Stage 8: `join`

Stage 9: `project-reorder`

Stage 10: `extend`

Stage 11: `extend`