Detection rules › Kusto

Cisco Duo - New access device

Status
available
Severity
medium
Time window
14d
Group by
DstUserName
Source
github.com/Azure/Azure-Sentinel

'Detects new access device.'

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1078 Valid Accounts

Rule body kusto

id: f05271b6-26a5-49cf-ad73-4a202fba6eb6
name: Cisco Duo - New access device
description: |
  'Detects new access device.'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: CiscoDuoSecurity
    dataTypes:
      - CiscoDuo
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T1078
query: |
  CiscoDuo
  | where EventType =~ 'authentication'
  | where EventResult =~ 'success'
  | where isnotempty(AccessDvcIpAddr)
  | summarize dvc_ip = makeset(AccessDvcIpAddr) by DstUserName
  | join (CiscoDuo
          | where EventType =~ 'authentication'
          | where EventResult =~ 'success') on DstUserName
  | where dvc_ip !has AccessDvcIpAddr
  | extend IPCustomEntity = AccessDvcIpAddr, AccountCustomEntity = DstUserName
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPCustomEntity
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountCustomEntity
version: 1.0.0
kind: Scheduled

Stages and Predicates

Stage 1: source

CiscoDuo

Stage 2: where

| where EventType =~ 'authentication'

Stage 3: where

| where EventResult =~ 'success'

Stage 4: where

| where isnotempty(AccessDvcIpAddr)

Stage 5: summarize

| summarize dvc_ip = makeset(AccessDvcIpAddr) by DstUserName

Stage 6: join

| join (CiscoDuo
        | where EventType =~ 'authentication'
        | where EventResult =~ 'success') on DstUserName

Stage 7: where

| where dvc_ip !has AccessDvcIpAddr

Stage 8: extend

| extend IPCustomEntity = AccessDvcIpAddr, AccountCustomEntity = DstUserName

Exclusions

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

FieldKindExcluded values
dvc_ipmatchAccessDvcIpAddr

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.

FieldKindValues
AccessDvcIpAddris_not_null
  • (no value, null check)
EventResulteq
  • success
EventTypeeq
  • authentication

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.

FieldSource
DstUserNamesummarize
dvc_ipsummarize
AccountCustomEntityextend
IPCustomEntityextend