Detection rules › Kusto
Cisco WSA - Unscannable file or scan error
'Detects unscanned downloaded file.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | T1189 Drive-by Compromise |
Rule body kusto
id: 9b61a945-ebcb-4245-b6e4-51f3addb5248
name: Cisco WSA - Unscannable file or scan error
description: |
'Detects unscanned downloaded file.'
severity: Medium
status: Available
requiredDataConnectors:
- connectorId: SyslogAma
datatypes:
- Syslog
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
relevantTechniques:
- T1189
query: |
CiscoWSAEvent
| where isnotempty(AmpFileName)
| where AmpScanningVerdict in ('2', '3')
| extend IPCustomEntity = SrcIpAddr, FileCustomEntity = AmpFileName, AccountCustomEntity = SrcUserName
entityMappings:
- entityType: IP
fieldMappings:
- identifier: Address
columnName: IPCustomEntity
- entityType: File
fieldMappings:
- identifier: Name
columnName: FileCustomEntity
- entityType: Account
fieldMappings:
- identifier: Name
columnName: AccountCustomEntity
version: 1.0.2
kind: Scheduled
Stages and Predicates
Stage 1: source
CiscoWSAEvent
Stage 2: where
| where isnotempty(AmpFileName)
Stage 3: where
| where AmpScanningVerdict in ('2', '3')
Stage 4: extend
| extend IPCustomEntity = SrcIpAddr, FileCustomEntity = AmpFileName, AccountCustomEntity = SrcUserName
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 |
|---|---|---|
AmpFileName | is_not_null | |
AmpScanningVerdict | in |
|
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 |
FileCustomEntity | extend |
IPCustomEntity | extend |