Dataverse - New user agent type that was not used before

Status: available
Severity: low
Time window: 14d
Group by: InstanceUrl, UserAgent, UserId
Source: github.com/Azure/Azure-Sentinel

Identifies users accessing Dataverse from a User Agent that has not been seen in any Dataverse instance in the last 14 days.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1078` Valid Accounts
Stealth	`T1036` Masquerading, `T1078` Valid Accounts
Initial Access	`T0819` Exploit Public-Facing Application, `T0866` Exploitation of Remote Services
Lateral Movement	`T0866` Exploitation of Remote Services

Rule body kusto

id: 34a5d79b-8f9a-420c-aa64-7f4d262ac29a
kind: Scheduled
name: Dataverse - New user agent type that was not used before
description: Identifies users accessing Dataverse from a User Agent that has not been
  seen in any Dataverse instance in the last 14 days.
severity: Low
status: Available
requiredDataConnectors:
  - connectorId: Dataverse
    dataTypes:
      - DataverseActivity
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
  - DefenseEvasion
relevantTechniques:
  - T1078
  - T0866
  - T0819
  - T1036
query: |
  let query_lookback = 14d;
  let query_frequency = 1h;
  let known_useragents = dynamic([
      // Enter known user agents to exclude.
      // example:
      // "Agent1", "Agent2", "Agent3"
      ]);
  DataverseActivity
  | where TimeGenerated between(ago(query_lookback) .. ago(query_frequency))
  | where isnotempty(UserAgent)
  | summarize by UserAgent
  | join kind = rightanti (DataverseActivity
      | where TimeGenerated > ago(query_frequency)
      | where not (UserId has_any ("@onmicrosoft.com", "@microsoft.com", "Unknown"))
      | where isnotempty(UserAgent)
      | where UserAgent !in~ (known_useragents)
      | where UserAgent !hasprefix "azure-logic-apps" and UserAgent !hasprefix "PowerApps")
      on UserAgent
  // Exclude user agents with a render agent to reduce noise.
  | join kind = leftanti(
      DataverseActivity
      | where TimeGenerated > ago(query_frequency)
      | where UserAgent has_any ("Gecko", "WebKit", "Presto", "Trident", "EdgeHTML", "Blink"))
      on UserAgent
  | summarize
      FirstSeen = min(TimeGenerated),
      LatestIP = arg_max(ClientIp, TimeGenerated)
      by UserAgent, UserId, InstanceUrl
  | extend
      AccountName = tostring(split(UserId, '@')[0]),
      UPNSuffix = tostring(split(UserId, '@')[1]),
      CloudAppId = int(32780)
  | project
      FirstSeen,
      UserId,
      UserAgent,
      LatestIP,
      InstanceUrl,
      CloudAppId,
      AccountName,
      UPNSuffix
eventGroupingSettings:
  aggregationKind: AlertPerResult
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: CloudApplication
    fieldMappings:
      - identifier: AppId
        columnName: CloudAppId
      - identifier: InstanceName
        columnName: InstanceUrl
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: LatestIP
alertDetailsOverride:
  alertDisplayNameFormat: 'Dataverse - new user agent detected in {{{InstanceUrl}} '
  alertDescriptionFormat: |
    {{UserId}} with new agent not seen previously in the Dataverse activity log.
    Agent: {{UserAgent}}
    Latest IP: {{LatestIP}}
version: 3.2.0

Stages and Predicates

Parameters

let query_lookback = 14d;
let query_frequency = 1h;

Let binding: `known_useragents`

let known_useragents = dynamic([
    ]);

Stage 1: `source`

DataverseActivity

Stage 2: `where`

| where TimeGenerated between(ago(query_lookback) .. ago(query_frequency))

Stage 3: `where`

| where isnotempty(UserAgent)

Stage 4: `summarize`

| summarize by UserAgent

Stage 5: `join` (negated)

| join kind = rightanti (DataverseActivity
    | where TimeGenerated > ago(query_frequency)
    | where not (UserId has_any ("@onmicrosoft.com", "@microsoft.com", "Unknown"))
    | where isnotempty(UserAgent)
    | where UserAgent !in~ (known_useragents)
    | where UserAgent !hasprefix "azure-logic-apps" and UserAgent !hasprefix "PowerApps")
    on UserAgent

Stage 6: `join` (negated)

| join kind = leftanti(
    DataverseActivity
    | where TimeGenerated > ago(query_frequency)
    | where UserAgent has_any ("Gecko", "WebKit", "Presto", "Trident", "EdgeHTML", "Blink"))
    on UserAgent

Stage 7: `summarize`

| summarize
    FirstSeen = min(TimeGenerated),
    LatestIP = arg_max(ClientIp, TimeGenerated)
    by UserAgent, UserId, InstanceUrl

Stage 8: `extend`

| extend
    AccountName = tostring(split(UserId, '@')[0]),
    UPNSuffix = tostring(split(UserId, '@')[1]),
    CloudAppId = int(32780)

Stage 9: `project`

| project
    FirstSeen,
    UserId,
    UserAgent,
    LatestIP,
    InstanceUrl,
    CloudAppId,
    AccountName,
    UPNSuffix

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`UserAgent`	is_not_null	(no value, null check)
`UserAgent`	match	`Gecko`, `WebKit`, `Presto`, `Trident`, `EdgeHTML`, `Blink`

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
`UserAgent`	in	`[]`
`UserAgent`	is_not_null	(no value, null check)
`UserAgent`	starts_with	`PowerApps` `azure-logic-apps`
`UserId`	match	`@microsoft.com` `@onmicrosoft.com` `Unknown`

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
`AccountName`	`project`
`CloudAppId`	`project`
`FirstSeen`	`project`
`InstanceUrl`	`project`
`LatestIP`	`project`
`UPNSuffix`	`project`
`UserAgent`	`project`
`UserId`	`project`

`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)

Dataverse - New user agent type that was not used before

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: `known_useragents`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `summarize`

Stage 5: `join` (negated)

Stage 6: `join` (negated)

Stage 7: `summarize`

Stage 8: `extend`

Stage 9: `project`

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

Dataverse - New user agent type that was not used before

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: known_useragents

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: summarize

Stage 5: join (negated)

Stage 6: join (negated)

Stage 7: summarize

Stage 8: extend

Stage 9: project

Exclusions

Indicators

Output fields

Let binding: `known_useragents`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `summarize`

Stage 5: `join` (negated)

Stage 6: `join` (negated)

Stage 7: `summarize`

Stage 8: `extend`

Stage 9: `project`