Detections/MultipleDataSources/SigninFirewallCorrelation.yaml

id: 157c0cfc-d76d-463b-8755-c781608cdc1a
name: Cisco - firewall block but success logon to Microsoft Entra ID
description: |
  'Correlate IPs blocked by a Cisco firewall appliance with successful Microsoft Entra ID signins.
  Because the IP was blocked by the firewall, that same IP logging on successfully to Entra ID is potentially suspect and could indicate credential compromise for the user account.'
severity: Medium
requiredDataConnectors:
  - connectorId: CiscoASA
    dataTypes:
      - CommonSecurityLog
  - connectorId: AzureActiveDirectory
    dataTypes:
     - SigninLogs
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AADNonInteractiveUserSignInLogs
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T1078
query: |
  let aadFunc = (tableName:string){
  CommonSecurityLog
  | where DeviceVendor =~ "Cisco"
  | where DeviceAction =~ "denied"
  | where ipv4_is_private(SourceIP) == false
  | summarize count() by SourceIP
  | join (
      // Successful signins from IPs blocked by the firewall solution are suspect
      // Include fully successful sign-ins, but also ones that failed only at MFA stage
      // as that supposes the password was sucessfully guessed.
    table(tableName)
    | where ResultType in ("0", "50074", "50076")
  ) on $left.SourceIP == $right.IPAddress
  | extend AccountName = tostring(split(Account, "@")[0]), AccountUPNSuffix = tostring(split(Account, "@")[1])
  };
  let aadSignin = aadFunc("SigninLogs");
  let aadNonInt = aadFunc("AADNonInteractiveUserSignInLogs");
  union isfuzzy=true aadSignin, aadNonInt
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: UserPrincipalName
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIP
version: 1.0.6
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Resarch
    support:
        tier: Community
    categories:
        domains: [ "Security - Network" ]