kqlMITfrom Azure/Azure-Sentinel
Rare RDP Connections
'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'
Quality
100
FP risk
—
Forks
0
Views
0
ATT&CK techniques
Rule sourceDetections/SecurityEvent/RDP_RareConnection.yaml
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