Detection rules › Kusto
Cisco Duo - Unexpected authentication factor
'Detects when unexpected authentication factor used.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | T1078 Valid Accounts |
Rule body kusto
id: 16c91a2c-17ad-4985-a9ad-4a4f1cb11830
name: Cisco Duo - Unexpected authentication factor
description: |
'Detects when unexpected authentication factor used.'
severity: Medium
status: Available
requiredDataConnectors:
- connectorId: CiscoDuoSecurity
dataTypes:
- CiscoDuo
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
relevantTechniques:
- T1078
query: |
let allowed_auth_f = dynamic(['duo_push', 'duo_mobile_passcode']);
CiscoDuo
| where EventType =~ 'authentication'
| where EventResult =~ 'success'
| where AuthFactor !in~ (allowed_auth_f)
| extend IPCustomEntity = SrcIpAddr, 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
Parameters
let allowed_auth_f = dynamic(['duo_push', 'duo_mobile_passcode']);
Stage 1: source
CiscoDuo
Stage 2: where
| where EventType =~ 'authentication'
Stage 3: where
| where EventResult =~ 'success'
Stage 4: where
| where AuthFactor !in~ (allowed_auth_f)
Stage 5: extend
| extend IPCustomEntity = SrcIpAddr, AccountCustomEntity = DstUserName
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
AuthFactor | in | duo_mobile_passcode, duo_push |
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 |
|---|---|---|
EventResult | eq |
|
EventType | eq |
|
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 |
|---|---|
AccountCustomEntity | extend |
IPCustomEntity | extend |