MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access |
Rule body
id: 52c4640a-1e2b-4155-b69e-e1869c9a57c9
name: Trend Micro CAS - Suspicious filename
description: |
'Detects unexpected filename.'
severity: Medium
status: Available
requiredDataConnectors:
- connectorId: TrendMicroCAS
dataTypes:
- TrendMicroCAS
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
relevantTechniques:
- T1566
query: |
TrendMicroCAS
| where isnotempty(SrcFileName)
| where SrcFileName matches regex @'\A[a-zA-Z0-9_\-.]{1,3}\.\w+$'
| extend AccountCustomEntity = DstUserName
entityMappings:
- entityType: Account
fieldMappings:
- identifier: Name
columnName: AccountCustomEntity
version: 1.0.0
kind: Scheduled
Stages and Predicates
Stage 1: source
TrendMicroCAS
Stage 2: where
| where isnotempty(SrcFileName)
Stage 3: where
| where SrcFileName matches regex @'\A[a-zA-Z0-9_\-.]{1,3}\.\w+$'
Stage 4: extend
| extend AccountCustomEntity = DstUserName
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
SrcFileName | is_not_null | field:"SrcFileName" kind:is_not_null | |
SrcFileName | regex_match |
| field:"SrcFileName" kind:regex_match value:"\A[a-zA-Z0-9_\-.]{1,3}.\w+$" |
Output fields
These fields are emitted when the rule matches.
| Field | Source |
|---|---|
AccountCustomEntity | extend |