Detection rules › Kusto

GreyNoise TI Map IP Entity to SigninLogs

Severity
medium
Time window
14d
Source
github.com/Azure/Azure-Sentinel

'This query maps any GreyNoise IP indicators of compromise (IOCs) from threat intelligence (TI), by searching for matches in SigninLogs.'

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1071 Application Layer Protocol

Rule body kusto

id: f6c76cc9-218c-5b76-9b82-8607f09ea1b4
name: GreyNoise TI Map IP Entity to SigninLogs
version: 1.0.1
kind: Scheduled
description: |
  'This query maps any GreyNoise IP indicators of compromise (IOCs) from threat intelligence (TI), by searching for matches in SigninLogs.'
severity: Medium
requiredDataConnectors:
  - connectorId: ThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: AzureActiveDirectory
    dataTypes:
      - SigninLogs
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AADNonInteractiveUserSignInLogs
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: GreyNoise2SentinelAPI
    dataTypes:
      - ThreatIntelligenceIndicator
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CommandAndControl
relevantTechniques:
  - T1071
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let aadFunc = (tableName:string){
  ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true and ExpirationDateTime > now()
  | where SourceSystem == 'GreyNoise'
  // Picking up only IOC's that contain the entities we want
  | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
  // As there is potentially more than 1 indicator type for matching IP, taking NetworkIP first, then others if that is empty.
  // Taking the first non-empty value based on potential IOC match availability
  | extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
  // 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 (
      table(tableName) | where TimeGenerated >= ago(dt_lookBack)
      | extend Status = todynamic(Status), LocationDetails = todynamic(LocationDetails)
      | extend StatusCode = tostring(Status.errorCode), StatusDetails = tostring(Status.additionalDetails), StatusReason = tostring(Status.failureReason)
      | extend State = tostring(LocationDetails.state), City = tostring(LocationDetails.city), Region = tostring(LocationDetails.countryOrRegion)
      // renaming time column so it is clear the log this came from
      | extend SigninLogs_TimeGenerated = TimeGenerated, Type = Type
  )
  on $left.TI_ipEntity == $right.IPAddress
  | where SigninLogs_TimeGenerated < ExpirationDateTime
  | summarize SigninLogs_TimeGenerated = arg_max(SigninLogs_TimeGenerated, *) by IndicatorId, IPAddress
  | project SigninLogs_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
  TI_ipEntity, IPAddress, UserPrincipalName, AppDisplayName, StatusCode, StatusDetails, StatusReason, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
  | extend timestamp = SigninLogs_TimeGenerated, Name = tostring(split(UserPrincipalName, '@', 0)[0]), UPNSuffix = tostring(split(UserPrincipalName, '@', 1)[0])
  };
  let aadSignin = aadFunc("SigninLogs");
  let aadNonInt = aadFunc("AADNonInteractiveUserSignInLogs");
  union isfuzzy=true aadSignin, aadNonInt
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: Name
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPAddress
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Url

Stages and Predicates

Parameters

let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let aadSignin = aadFunc("SigninLogs");
let aadNonInt = aadFunc("AADNonInteractiveUserSignInLogs");

Let binding: aadFunc

let aadFunc = (tableName:string){
ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
| where SourceSystem == 'GreyNoise'
| where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
| extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
| extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
| extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
| join kind=innerunique (
    table(tableName) | where TimeGenerated >= ago(dt_lookBack)
    | extend Status = todynamic(Status), LocationDetails = todynamic(LocationDetails)
    | extend StatusCode = tostring(Status.errorCode), StatusDetails = tostring(Status.additionalDetails), StatusReason = tostring(Status.failureReason)
    | extend State = tostring(LocationDetails.state), City = tostring(LocationDetails.city), Region = tostring(LocationDetails.countryOrRegion)
    | extend SigninLogs_TimeGenerated = TimeGenerated, Type = Type
)
on $left.TI_ipEntity == $right.IPAddress
| where SigninLogs_TimeGenerated < ExpirationDateTime
| summarize SigninLogs_TimeGenerated = arg_max(SigninLogs_TimeGenerated, *) by IndicatorId, IPAddress
| project SigninLogs_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
TI_ipEntity, IPAddress, UserPrincipalName, AppDisplayName, StatusCode, StatusDetails, StatusReason, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
| extend timestamp = SigninLogs_TimeGenerated, Name = tostring(split(UserPrincipalName, '@', 0)[0]), UPNSuffix = tostring(split(UserPrincipalName, '@', 1)[0])
};

Derived from dt_lookBack, ioc_lookBack.

union isfuzzy=true (2 sources)

Each leg below queries one source; the rule matches if any leg does. Sources: aadSignin, aadNonInt

Leg 1: aadSignin

Leg 2: aadNonInt