Rare RDP Connections

Back


Id	45b903c5-6f56-4969-af10-ae62ac709718
Rulename	Rare RDP Connections
Description	Identifies when an RDP connection is new or rare related to any logon type by a given account today compared with the previous 14 days. RDP connections are indicated by the EventID 4624 with LogonType = 10
Severity	Medium
Tactics	LateralMovement
Techniques	T1021
Required data connectors	SecurityEvents WindowsForwardedEvents WindowsSecurityEvents
Kind	Scheduled
Query frequency	1d
Query period	14d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/RDP_RareConnection.yaml
Version	1.2.5
Arm template	45b903c5-6f56-4969-af10-ae62ac709718.json

KQL

let starttime = 14d;
let endtime = 1d;
(union isfuzzy=true
(SecurityEvent
| where TimeGenerated >= ago(endtime)
| where EventID == 4624 and LogonType == 10
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ConnectionCount = count()
by Account = tolower(Account), Computer = toupper(Computer), IpAddress, AccountType, Activity, LogonTypeName, ProcessName
// use left anti to exclude anything from the previous 14 days that is not rare
),
(WindowsEvent
| where TimeGenerated >= ago(endtime)
| where EventID == 4624 and EventData has ("10")
| extend LogonType = tostring(EventData.LogonType)
| where  LogonType == 10
| extend Account = strcat(tostring(EventData.TargetDomainName),"\\", tostring(EventData.TargetUserName))
| extend ProcessName = tostring(EventData.ProcessName)
| extend IpAddress = tostring(EventData.IpAddress)
| extend TargetUserSid = tostring(EventData.TargetUserSid)
| extend AccountType=case(Account endswith "$" or TargetUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(TargetUserSid), "", "User")
| extend Activity="4624 - An account was successfully logged on."
| extend LogonTypeName="10 - RemoteInteractive"
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ConnectionCount = count()
by Account = tolower(Account), Computer = toupper(Computer), IpAddress, AccountType, Activity, LogonTypeName, ProcessName
))
| join kind=leftanti (
(union isfuzzy=true
(SecurityEvent
| where TimeGenerated between (ago(starttime) .. ago(endtime))
| where EventID == 4624
| summarize by Computer = toupper(Computer), IpAddress, Account = tolower(Account)
),
( WindowsEvent
| where TimeGenerated between (ago(starttime) .. ago(endtime))
| where EventID == 4624
| extend IpAddress = tostring(EventData.IpAddress)
| extend Account = strcat(tostring(EventData.TargetDomainName),"\\", tostring(EventData.TargetUserName))
| summarize by Computer = toupper(Computer), IpAddress, Account = tolower(Account)
))
) on Account, Computer
| summarize StartTime = min(StartTime), EndTime = max(EndTime), ConnectionCount = sum(ConnectionCount)
by Account, Computer, IpAddress, AccountType, Activity, LogonTypeName, ProcessName
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| extend AccountName = tostring(split(Account, @"\")[1]), AccountNTDomain = tostring(split(Account, @"\")[0])
| project-away DomainIndex

YAML

relevantTechniques:
- T1021
name: Rare RDP Connections
requiredDataConnectors:
- dataTypes:
  - SecurityEvent
  connectorId: SecurityEvents
- dataTypes:
  - SecurityEvent
  connectorId: WindowsSecurityEvents
- dataTypes:
  - WindowsEvent
  connectorId: WindowsForwardedEvents
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: Account
  - identifier: Name
    columnName: AccountName
  - identifier: NTDomain
    columnName: AccountNTDomain
  entityType: Account
- fieldMappings:
  - identifier: FullName
    columnName: Computer
  - identifier: HostName
    columnName: HostName
  - identifier: NTDomain
    columnName: HostNameDomain
  entityType: Host
- fieldMappings:
  - identifier: Address
    columnName: IpAddress
  entityType: IP
triggerThreshold: 0
id: 45b903c5-6f56-4969-af10-ae62ac709718
tactics:
- LateralMovement
version: 1.2.5
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/RDP_RareConnection.yaml
queryPeriod: 14d
kind: Scheduled
metadata:
  categories:
    domains:
    - Security - Threat Protection
  author:
    name: Microsoft Security Research
  support:
    tier: Community
  source:
    kind: Community
queryFrequency: 1d
severity: Medium
description: |
  'Identifies when an RDP connection is new or rare related to any logon type by a given account today compared with the previous 14 days.
  RDP connections are indicated by the EventID 4624 with LogonType = 10'  
query: |
  let starttime = 14d;
  let endtime = 1d;
  (union isfuzzy=true
  (SecurityEvent
  | where TimeGenerated >= ago(endtime)
  | where EventID == 4624 and LogonType == 10
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ConnectionCount = count()
  by Account = tolower(Account), Computer = toupper(Computer), IpAddress, AccountType, Activity, LogonTypeName, ProcessName
  // use left anti to exclude anything from the previous 14 days that is not rare
  ),
  (WindowsEvent
  | where TimeGenerated >= ago(endtime)
  | where EventID == 4624 and EventData has ("10")
  | extend LogonType = tostring(EventData.LogonType)
  | where  LogonType == 10
  | extend Account = strcat(tostring(EventData.TargetDomainName),"\\", tostring(EventData.TargetUserName))
  | extend ProcessName = tostring(EventData.ProcessName)
  | extend IpAddress = tostring(EventData.IpAddress)
  | extend TargetUserSid = tostring(EventData.TargetUserSid)
  | extend AccountType=case(Account endswith "$" or TargetUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(TargetUserSid), "", "User")
  | extend Activity="4624 - An account was successfully logged on."
  | extend LogonTypeName="10 - RemoteInteractive"
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ConnectionCount = count()
  by Account = tolower(Account), Computer = toupper(Computer), IpAddress, AccountType, Activity, LogonTypeName, ProcessName
  ))
  | join kind=leftanti (
  (union isfuzzy=true
  (SecurityEvent
  | where TimeGenerated between (ago(starttime) .. ago(endtime))
  | where EventID == 4624
  | summarize by Computer = toupper(Computer), IpAddress, Account = tolower(Account)
  ),
  ( WindowsEvent
  | where TimeGenerated between (ago(starttime) .. ago(endtime))
  | where EventID == 4624
  | extend IpAddress = tostring(EventData.IpAddress)
  | extend Account = strcat(tostring(EventData.TargetDomainName),"\\", tostring(EventData.TargetUserName))
  | summarize by Computer = toupper(Computer), IpAddress, Account = tolower(Account)
  ))
  ) on Account, Computer
  | summarize StartTime = min(StartTime), EndTime = max(EndTime), ConnectionCount = sum(ConnectionCount)
  by Account, Computer, IpAddress, AccountType, Activity, LogonTypeName, ProcessName
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
  | extend AccountName = tostring(split(Account, @"\")[1]), AccountNTDomain = tostring(split(Account, @"\")[0])
  | project-away DomainIndex  
triggerOperator: gt

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/45b903c5-6f56-4969-af10-ae62ac709718')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/45b903c5-6f56-4969-af10-ae62ac709718')]",
      "properties": {
        "alertRuleTemplateName": "45b903c5-6f56-4969-af10-ae62ac709718",
        "customDetails": null,
        "description": "'Identifies when an RDP connection is new or rare related to any logon type by a given account today compared with the previous 14 days.\nRDP connections are indicated by the EventID 4624 with LogonType = 10'\n",
        "displayName": "Rare RDP Connections",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Account",
                "identifier": "FullName"
              },
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountNTDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "Computer",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "HostNameDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "IpAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/RDP_RareConnection.yaml",
        "query": "let starttime = 14d;\nlet endtime = 1d;\n(union isfuzzy=true\n(SecurityEvent\n| where TimeGenerated >= ago(endtime)\n| where EventID == 4624 and LogonType == 10\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ConnectionCount = count()\nby Account = tolower(Account), Computer = toupper(Computer), IpAddress, AccountType, Activity, LogonTypeName, ProcessName\n// use left anti to exclude anything from the previous 14 days that is not rare\n),\n(WindowsEvent\n| where TimeGenerated >= ago(endtime)\n| where EventID == 4624 and EventData has (\"10\")\n| extend LogonType = tostring(EventData.LogonType)\n| where  LogonType == 10\n| extend Account = strcat(tostring(EventData.TargetDomainName),\"\\\\\", tostring(EventData.TargetUserName))\n| extend ProcessName = tostring(EventData.ProcessName)\n| extend IpAddress = tostring(EventData.IpAddress)\n| extend TargetUserSid = tostring(EventData.TargetUserSid)\n| extend AccountType=case(Account endswith \"$\" or TargetUserSid in (\"S-1-5-18\", \"S-1-5-19\", \"S-1-5-20\"), \"Machine\", isempty(TargetUserSid), \"\", \"User\")\n| extend Activity=\"4624 - An account was successfully logged on.\"\n| extend LogonTypeName=\"10 - RemoteInteractive\"\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ConnectionCount = count()\nby Account = tolower(Account), Computer = toupper(Computer), IpAddress, AccountType, Activity, LogonTypeName, ProcessName\n))\n| join kind=leftanti (\n(union isfuzzy=true\n(SecurityEvent\n| where TimeGenerated between (ago(starttime) .. ago(endtime))\n| where EventID == 4624\n| summarize by Computer = toupper(Computer), IpAddress, Account = tolower(Account)\n),\n( WindowsEvent\n| where TimeGenerated between (ago(starttime) .. ago(endtime))\n| where EventID == 4624\n| extend IpAddress = tostring(EventData.IpAddress)\n| extend Account = strcat(tostring(EventData.TargetDomainName),\"\\\\\", tostring(EventData.TargetUserName))\n| summarize by Computer = toupper(Computer), IpAddress, Account = tolower(Account)\n))\n) on Account, Computer\n| summarize StartTime = min(StartTime), EndTime = max(EndTime), ConnectionCount = sum(ConnectionCount)\nby Account, Computer, IpAddress, AccountType, Activity, LogonTypeName, ProcessName\n| extend HostName = tostring(split(Computer, \".\")[0]), DomainIndex = toint(indexof(Computer, '.'))\n| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)\n| extend AccountName = tostring(split(Account, @\"\\\")[1]), AccountNTDomain = tostring(split(Account, @\"\\\")[0])\n| project-away DomainIndex\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "LateralMovement"
        ],
        "techniques": [
          "T1021"
        ],
        "templateVersion": "1.2.5",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}