Detection rules › Kusto

Cisco SE - Unexpected binary file

Status
available
Severity
medium
Time window
1h
Source
github.com/Azure/Azure-Sentinel

'Detects binary files in uncommon locations.'

MITRE ATT&CK coverage

Rule body kusto

id: eabb9c20-7b0b-4a77-81e8-b06944f351c6
name: Cisco SE - Unexpected binary file
description: |
  'Detects binary files in uncommon locations.'
severity: Medium
requiredDataConnectors:
  - connectorId: CiscoSecureEndpoint
    dataTypes:
      - CiscoSecureEndpoint
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
status: Available
tactics:
  - InitialAccess
relevantTechniques:
  - T1190
  - T1133
query: |
  CiscoSecureEndpoint
  | where isnotempty(SrcFileName)
  | where SrcFilePath contains @'AppData\Local\Temp' or SrcFilePath contains @'OUTLOOK_TEMP'
  | extend ext = extract(@"(.*\/)?(.*)", 2, tostring(SrcFilePath))
  | where ext contains 'dll' or ext contains @'ps1' or ext contains @'exe'
  | extend HostCustomEntity = DstHostname
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: HostCustomEntity
version: 1.0.0
kind: Scheduled

Stages and Predicates

Stage 1: source

CiscoSecureEndpoint

Stage 2: where

| where isnotempty(SrcFileName)

Stage 3: where

| where SrcFilePath contains @'AppData\Local\Temp' or SrcFilePath contains @'OUTLOOK_TEMP'

Stage 4: extend

| extend ext = extract(@"(.*\/)?(.*)", 2, tostring(SrcFilePath))

Stage 5: where

| where ext contains 'dll' or ext contains @'ps1' or ext contains @'exe'

Stage 6: extend

| extend HostCustomEntity = DstHostname

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
SrcFileNameis_not_null
  • (no value, null check)
SrcFilePathcontains
  • AppData\Local\Temp
  • OUTLOOK_TEMP
extcontains
  • dll
  • exe
  • ps1

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
extextend
HostCustomEntityextend