Detection rules › Kusto
TI map File Hash to Security Event
'Identifies a match in Security Event data from any File Hash IOC from TI'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Command & Control | T1071 Application Layer Protocol |
Rule body kusto
id: a7427ed7-04b4-4e3b-b323-08b981b9b4bf
name: TI map File Hash to Security Event
description: |
'Identifies a match in Security Event data from any File Hash IOC from TI'
severity: Medium
requiredDataConnectors:
- connectorId: SecurityEvents
dataTypes:
- SecurityEvent
- connectorId: WindowsSecurityEvents
dataTypes:
- SecurityEvents
- connectorId: WindowsForwardedEvents
dataTypes:
- WindowsEvent
- connectorId: ThreatIntelligence
dataTypes:
- ThreatIntelligenceIndicator
- connectorId: ThreatIntelligenceTaxii
dataTypes:
- ThreatIntelligenceIndicator
- connectorId: MicrosoftDefenderThreatIntelligence
dataTypes:
- ThreatIntelligenceIndicator
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
- CommandAndControl
relevantTechniques:
- T1071
query: |
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
ThreatIntelligenceIndicator
| where isnotempty(FileHashValue)
| where TimeGenerated >= ago(ioc_lookBack)
| extend FileHashValue = toupper(FileHashValue)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
// using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
| join kind=innerunique ( union isfuzzy=true
(SecurityEvent | where TimeGenerated >= ago(dt_lookBack)
| where EventID in ("8003","8002","8005")
| where isnotempty(FileHash)
| extend SecurityEvent_TimeGenerated = TimeGenerated, Event = EventID, FileHash = toupper(FileHash)
),
(WindowsEvent | where TimeGenerated >= ago(dt_lookBack)
| where EventID in ("8003","8002","8005")
| where isnotempty(EventData.FileHash)
| extend SecurityEvent_TimeGenerated = TimeGenerated, Event = EventID, FileHash = toupper(EventData.FileHash)
)
)
on $left.FileHashValue == $right.FileHash
| where SecurityEvent_TimeGenerated < ExpirationDateTime
| summarize SecurityEvent_TimeGenerated = arg_max(SecurityEvent_TimeGenerated, *) by IndicatorId, FileHash
| project SecurityEvent_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
Process, FileHash, Computer, Account, Event, FileHashValue, FileHashType
| extend NTDomain = tostring(split(Account, '\\', 0)[0]), Name = tostring(split(Account, '\\', 1)[0])
| extend HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))
| extend timestamp = SecurityEvent_TimeGenerated
entityMappings:
- entityType: Account
fieldMappings:
- identifier: FullName
columnName: Account
- identifier: Name
columnName: Name
- identifier: NTDomain
columnName: NTDomain
- entityType: Host
fieldMappings:
- identifier: FullName
columnName: Computer
- identifier: HostName
columnName: HostName
- identifier: DnsDomain
columnName: DnsDomain
- entityType: URL
fieldMappings:
- identifier: Url
columnName: Url
- entityType: FileHash
fieldMappings:
- identifier: Value
columnName: FileHashValue
- identifier: Algorithm
columnName: FileHashType
version: 1.4.6
kind: Scheduled
Stages and Predicates
Parameters
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
Stage 1: source
ThreatIntelligenceIndicator
Stage 2: where
| where isnotempty(FileHashValue)
Stage 3: where
| where TimeGenerated >= ago(ioc_lookBack)
Stage 4: extend
| extend FileHashValue = toupper(FileHashValue)
Stage 5: summarize
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
Stage 6: where
| where Active == true and ExpirationDateTime > now()
Stage 7: join
| join kind=innerunique ( union isfuzzy=true
(SecurityEvent | where TimeGenerated >= ago(dt_lookBack)
| where EventID in ("8003","8002","8005")
| where isnotempty(FileHash)
| extend SecurityEvent_TimeGenerated = TimeGenerated, Event = EventID, FileHash = toupper(FileHash)
),
(WindowsEvent | where TimeGenerated >= ago(dt_lookBack)
| where EventID in ("8003","8002","8005")
| where isnotempty(EventData.FileHash)
| extend SecurityEvent_TimeGenerated = TimeGenerated, Event = EventID, FileHash = toupper(EventData.FileHash)
)
)
on $left.FileHashValue == $right.FileHash
Stage 8: where
| where SecurityEvent_TimeGenerated < ExpirationDateTime
Stage 9: summarize
| summarize SecurityEvent_TimeGenerated = arg_max(SecurityEvent_TimeGenerated, *) by IndicatorId, FileHash
Stage 10: project
| project SecurityEvent_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
Process, FileHash, Computer, Account, Event, FileHashValue, FileHashType
Stage 11: extend (3 consecutive steps)
| extend NTDomain = tostring(split(Account, '\\', 0)[0]), Name = tostring(split(Account, '\\', 1)[0])
| extend HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))
| extend timestamp = SecurityEvent_TimeGenerated
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 |
|---|---|---|
Active | eq |
|
EventID | in |
|
FileHash | is_not_null | |
FileHashValue | is_not_null | |
SecurityEvent_TimeGenerated | lt |
|
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 |
|---|---|
Account | project |
ActivityGroupNames | project |
Computer | project |
ConfidenceScore | project |
Description | project |
Event | project |
ExpirationDateTime | project |
FileHash | project |
FileHashType | project |
FileHashValue | project |
IndicatorId | project |
Process | project |
SecurityEvent_TimeGenerated | project |
ThreatType | project |
Url | project |
NTDomain | extend |
Name | extend |
DnsDomain | extend |
HostName | extend |
timestamp | extend |