Microsoft COVID-19 file hash indicator matches

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Id	2be4ef67-a93f-4d8a-981a-88158cb73abd
Rulename	Microsoft COVID-19 file hash indicator matches
Description	Identifies a match in CommonSecurityLog Event data from any FileHash published in the Microsoft COVID-19 Threat Intel Feed - as described at https://www.microsoft.com/security/blog/2020/05/14/open-sourcing-covid-threat-intelligence/
Severity	Medium
Tactics	Execution
Techniques	T1204.002
Required data connectors	CefAma
Kind	Scheduled
Query frequency	1h
Query period	14d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/PaloAlto-PAN-OS/Analytic Rules/FileHashEntity_Covid19_CommonSecurityLog.yaml
Version	1.3.6
Arm template	2be4ef67-a93f-4d8a-981a-88158cb73abd.json

KQL

let dt_lookBack = 1h;
let covidIndicators = (externaldata(TimeGenerated:datetime, FileHashValue:string, FileHashType: string, TlpLevel: string, Product: string, ThreatType: string, Description: string )
[@"https://raw.githubusercontent.com/Azure/Azure-Sentinel/master/Sample%20Data/Feeds/Microsoft.Covid19.Indicators.csv"] with (format="csv"));
let fileHashIndicators = covidIndicators
| where isnotempty(FileHashValue);
// Handle matches against both lower case and uppercase versions of the hash:
(fileHashIndicators | extend FileHashValue = tolower(FileHashValue)
| union (fileHashIndicators | extend FileHashValue = toupper(FileHashValue)))
// 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 (
   CommonSecurityLog | where TimeGenerated >= ago(dt_lookBack)
   | where isnotempty(FileHash)
   | extend CommonSecurityLog_TimeGenerated = TimeGenerated
   )
on $left.FileHashValue == $right.FileHash
| summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by FileHashValue
| project CommonSecurityLog_TimeGenerated, FileHashValue, FileHashType, Description, ThreatType,
SourceIP, SourcePort, DestinationIP, DestinationPort, SourceUserID, SourceUserName, DeviceName, DeviceAction,
RequestURL, DestinationUserName, DestinationUserID, ApplicationProtocol, Activity
| extend AccountName = tostring(split(SourceUserName, "@")[0]), AccountUPNSuffix = tostring(split(SourceUserName, "@")[1])
| extend HostName = tostring(split(DeviceName, ".")[0]), DomainIndex = toint(indexof(DeviceName, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)

YAML

relevantTechniques:
- T1204.002
queryFrequency: 1h
description: |
    'Identifies a match in CommonSecurityLog Event data from any FileHash published in the Microsoft COVID-19 Threat Intel Feed - as described at https://www.microsoft.com/security/blog/2020/05/14/open-sourcing-covid-threat-intelligence/'
severity: Medium
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: SourceUserName
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: AccountUPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: FullName
    columnName: DeviceName
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: HostNameDomain
  entityType: Host
- fieldMappings:
  - identifier: Address
    columnName: SourceIP
  entityType: IP
- fieldMappings:
  - identifier: Value
    columnName: FileHashValue
  - identifier: Algorithm
    columnName: FileHashType
  entityType: FileHash
triggerThreshold: 0
tactics:
- Execution
requiredDataConnectors:
- dataTypes:
  - CommonSecurityLog
  connectorId: CefAma
queryPeriod: 14d
id: 2be4ef67-a93f-4d8a-981a-88158cb73abd
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/PaloAlto-PAN-OS/Analytic Rules/FileHashEntity_Covid19_CommonSecurityLog.yaml
query: |
  let dt_lookBack = 1h;
  let covidIndicators = (externaldata(TimeGenerated:datetime, FileHashValue:string, FileHashType: string, TlpLevel: string, Product: string, ThreatType: string, Description: string )
  [@"https://raw.githubusercontent.com/Azure/Azure-Sentinel/master/Sample%20Data/Feeds/Microsoft.Covid19.Indicators.csv"] with (format="csv"));
  let fileHashIndicators = covidIndicators
  | where isnotempty(FileHashValue);
  // Handle matches against both lower case and uppercase versions of the hash:
  (fileHashIndicators | extend FileHashValue = tolower(FileHashValue)
  | union (fileHashIndicators | extend FileHashValue = toupper(FileHashValue)))
  // 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 (
     CommonSecurityLog | where TimeGenerated >= ago(dt_lookBack)
     | where isnotempty(FileHash)
     | extend CommonSecurityLog_TimeGenerated = TimeGenerated
     )
  on $left.FileHashValue == $right.FileHash
  | summarize CommonSecurityLog_TimeGenerated = arg_max(CommonSecurityLog_TimeGenerated, *) by FileHashValue
  | project CommonSecurityLog_TimeGenerated, FileHashValue, FileHashType, Description, ThreatType,
  SourceIP, SourcePort, DestinationIP, DestinationPort, SourceUserID, SourceUserName, DeviceName, DeviceAction,
  RequestURL, DestinationUserName, DestinationUserID, ApplicationProtocol, Activity
  | extend AccountName = tostring(split(SourceUserName, "@")[0]), AccountUPNSuffix = tostring(split(SourceUserName, "@")[1])
  | extend HostName = tostring(split(DeviceName, ".")[0]), DomainIndex = toint(indexof(DeviceName, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)  
name: Microsoft COVID-19 file hash indicator matches
version: 1.3.6
kind: Scheduled
status: Available

ARM