Multiple RDP connections from Single System

let endtime = 1d;
let starttime = 8d;
let threshold = 2.0;
(union isfuzzy=true
(SecurityEvent
| where TimeGenerated >= ago(endtime)
| where EventID == 4624 and LogonType == 10
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ComputerCountToday = dcount(Computer), ComputerSet = makeset(Computer), ProcessSet = makeset(ProcessName)
by Account = tolower(Account), IpAddress, AccountType, Activity, LogonTypeName),
(WindowsEvent
| where TimeGenerated >= ago(endtime)
| where EventID == 4624
| extend LogonType = tostring(EventData.LogonType)
| where  LogonType == 10
| extend ProcessName = tostring(EventData.ProcessName)
| extend Account = strcat(tostring(EventData.TargetDomainName),"\\", tostring(EventData.TargetUserName))
| 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), ComputerCountToday = dcount(Computer), ComputerSet = makeset(Computer), ProcessSet = makeset(ProcessName)
by Account = tolower(Account), IpAddress, AccountType, Activity, LogonTypeName)
)
| join kind=inner (
(union isfuzzy=true
(SecurityEvent
| where TimeGenerated >= ago(starttime) and TimeGenerated < ago(endtime)
| where EventID == 4624 and LogonType == 10
| summarize ComputerCountPrev7Days = dcount(Computer) by Account = tolower(Account), IpAddress
),
( WindowsEvent
| where TimeGenerated >= ago(starttime) and TimeGenerated < ago(endtime)
| where EventID == 4624  and EventData has ("10")
| extend LogonType = toint(EventData.LogonType)
| where  LogonType == 10
| extend Account = strcat(tostring(EventData.TargetDomainName),"\\", tostring(EventData.TargetUserName))
| extend IpAddress = tostring(EventData.IpAddress)
| summarize ComputerCountPrev7Days = dcount(Computer) by Account = tolower(Account), IpAddress)
)
) on Account, IpAddress
| extend Ratio = iff(isempty(ComputerCountPrev7Days), toreal(ComputerCountToday), ComputerCountToday / (ComputerCountPrev7Days * 1.0))
// Where the ratio of today to previous 7 days is more than double.
| where Ratio > threshold
| project StartTime, EndTime, Account, IpAddress, ComputerSet, ComputerCountToday, ComputerCountPrev7Days, Ratio, AccountType, Activity, LogonTypeName, ProcessSet
| extend AccountName = tostring(split(Account, @"\")[1]), AccountNTDomain = tostring(split(Account, @"\")[0])

description: |
  'Identifies when an RDP connection is made to multiple systems and above the normal connection count for the previous 7 days.
  Connections from the same system with the same account within the same day.
  RDP connections are indicated by the EventID 4624 with LogonType = 10'  
kind: Scheduled
tactics:
- LateralMovement
requiredDataConnectors:
- connectorId: SecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: WindowsSecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: WindowsForwardedEvents
  dataTypes:
  - WindowsEvent
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/RDP_MultipleConnectionsFromSingleSystem.yaml
severity: Low
name: Multiple RDP connections from Single System
metadata:
  support:
    tier: Community
  author:
    name: Microsoft Security Research
  categories:
    domains:
    - Security - Threat Protection
  source:
    kind: Community
triggerThreshold: 0
queryPeriod: 8d
query: |
  let endtime = 1d;
  let starttime = 8d;
  let threshold = 2.0;
  (union isfuzzy=true
  (SecurityEvent
  | where TimeGenerated >= ago(endtime)
  | where EventID == 4624 and LogonType == 10
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ComputerCountToday = dcount(Computer), ComputerSet = makeset(Computer), ProcessSet = makeset(ProcessName)
  by Account = tolower(Account), IpAddress, AccountType, Activity, LogonTypeName),
  (WindowsEvent
  | where TimeGenerated >= ago(endtime)
  | where EventID == 4624
  | extend LogonType = tostring(EventData.LogonType)
  | where  LogonType == 10
  | extend ProcessName = tostring(EventData.ProcessName)
  | extend Account = strcat(tostring(EventData.TargetDomainName),"\\", tostring(EventData.TargetUserName))
  | 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), ComputerCountToday = dcount(Computer), ComputerSet = makeset(Computer), ProcessSet = makeset(ProcessName)
  by Account = tolower(Account), IpAddress, AccountType, Activity, LogonTypeName)
  )
  | join kind=inner (
  (union isfuzzy=true
  (SecurityEvent
  | where TimeGenerated >= ago(starttime) and TimeGenerated < ago(endtime)
  | where EventID == 4624 and LogonType == 10
  | summarize ComputerCountPrev7Days = dcount(Computer) by Account = tolower(Account), IpAddress
  ),
  ( WindowsEvent
  | where TimeGenerated >= ago(starttime) and TimeGenerated < ago(endtime)
  | where EventID == 4624  and EventData has ("10")
  | extend LogonType = toint(EventData.LogonType)
  | where  LogonType == 10
  | extend Account = strcat(tostring(EventData.TargetDomainName),"\\", tostring(EventData.TargetUserName))
  | extend IpAddress = tostring(EventData.IpAddress)
  | summarize ComputerCountPrev7Days = dcount(Computer) by Account = tolower(Account), IpAddress)
  )
  ) on Account, IpAddress
  | extend Ratio = iff(isempty(ComputerCountPrev7Days), toreal(ComputerCountToday), ComputerCountToday / (ComputerCountPrev7Days * 1.0))
  // Where the ratio of today to previous 7 days is more than double.
  | where Ratio > threshold
  | project StartTime, EndTime, Account, IpAddress, ComputerSet, ComputerCountToday, ComputerCountPrev7Days, Ratio, AccountType, Activity, LogonTypeName, ProcessSet
  | extend AccountName = tostring(split(Account, @"\")[1]), AccountNTDomain = tostring(split(Account, @"\")[0])  
relevantTechniques:
- T1021
id: 78422ef2-62bf-48ca-9bab-72c69818a425
queryFrequency: 1d
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: Account
    identifier: FullName
  - columnName: AccountName
    identifier: Name
  - columnName: AccountNTDomain
    identifier: NTDomain
- entityType: IP
  fieldMappings:
  - columnName: IpAddress
    identifier: Address
triggerOperator: gt
version: 1.2.6