Tracking and Analyzing Remote Desktop Activity Logs in Windows

In this article we’ll consider the features of auditing and analyzing RDP connection logs in Windows. As a rule, the described methods may be useful when investigating RDP-related activity on RDS (terminal) Windows servers in forensics tasks, when a system administrator must provide the information about what users logged on to the RDS server, when a specific RDP user authenticated and ended up the session, which device (a name or IP address) an user connected from. I think this information will be useful both for the administrators of corporate RDS farms and for owners of a separate RDP servers what are published in the Internet (Windows VPS are still quite popular).The article is applicable when analyzing RDP logs both in Windows Server 2008 R2, 2012/R2, 2016 and in desktop Windows editions (Windows 10, 8.1 and 7).

You can check the RDP connection logs using Windows Event Viewer (eventvwr.msc). Windows logs contain a lot of data, and it is quite difficult to find the event you need. When a user remotely connects to the remote desktop of RDS (RDP), a whole number of events appears in the Windows Event Viewer. There are several different logs where you can find the information about Remote Desktop connections. We’ll look at the logs and events on the main stages of an RDP connection that may be of interest to the administrator:

1. Network Connection;
2. Authentication;
3. Logon;
4. Session Disconnect/Reconnect;
5. Logoff.

Network Connection is the establishment of a network connection to a server from a user RDP client. It is the event with the EventID 1149 (Remote Desktop Services: User authentication succeeded). If this event is found, it doesn’t mean that user authentication has been successful. This log is located in “Applications and Services Logs -> Microsoft -> Windows -> Terminal-Services-RemoteConnectionManager > Operational”. Enable the log filter for this event (right-click the log -> Filter Current Log -> EventId 1149).

Then you will get an event list with the history of all RDP connections to this server. As you can see, the logs provide a username, a domain (in this case the Network Level Authentication is used; if NLA is disabled, the event text looks differently) and the IP address of the computer, from which the RDP connection has been initiated.

Authentication shows whether an RDP user has been successfully authenticated on the server or not. The log is located in “Windows -> Security”. So you may be interested in the events with the EventID 4624 (An account was successfully logged on) or 4625 (An account failed to log on). Please, pay attention to the LogonType value in the event description. If the Remote Desktop service has been use to create new session during log on, LogonType = 10. If the LogonType = 7, it means that a user has reconnected to the existing RDP session.

At the same time, you can find a user name in the event description in the Account Name field, a computer name – in Workstation Name, and an IP address – in Source Network Address.Please, note the value of the TargetLogonID fiedl. It is a unique ID of a user RDP session that helps to track further activity of the user. However, if an RDP session is disconnected and a user reconnects to it, they will be assigned a new TargetLogonID (though an RDP session is still the same).

You can get the list of events related to successful RDP authentication (EventID 4624) using this PowerShell command:

Get-EventLog security -after (Get-date -hour 0 -minute 0 -second 0) | ?{$_.eventid -eq 4624 -and $_.Message -match 'logon type:\s+(10)\s'} | Out-GridView

Logon refers to an RDP logon to the system, an event that appears after a user has been successfully authenticated. It is an event with the EventID 21 (Remote Desktop Services: Session logon succeeded). This events are located in the “Applications and Services Logs -> Microsoft -> Windows -> TerminalServices-LocalSessionManager -> Operational”. As you can see, here you can find the ID of a user RDP session — Session ID.

The event with the EventID – 21 (Remote Desktop Services: Shell start notification received) means that the Explorer shell has been successfully started (the desktop  appears in the user’s RDP session).

Session Disconnect/Reconnect – session disconnection / reconnection events have different IDs depending on what caused user disconnection (disconnection to inactivity, Disconnect option has been selected by the user in the session, RDP session ended by another user or an administrator, etc.). You can find these events in the logs located in “Applications and Services Logs -> Microsoft -> Windows -> TerminalServices-LocalSessionManager -> Operational”. Let’s consider the most interesting RDP events:

• EventID – 24 (Remote Desktop Services: Session has been disconnected) – a user has disconnected from the RDP session;
• EventID – 25 (Remote Desktop Services: Session reconnection succeeded) – a user has reconnected to the existing RDP session on the server;
• EventID – 39 (Session <A> has been disconnected by session <B>) – a user has disconnected from RDP session by selecting the corresponding menu option (instead of just closing the RDP client window). If the session IDs are different, a user has been disconnected by another user (or an administrator);
• EventID – 40 (Session <A> has been disconnected, reason code <B>). Here you must view the disconnection reason code in the event description. For example:
  • reason code 0 (No additional information is available) usually means that a user has just closed the RDP client window;
  • reason code 5 (The client’s connection was replaced by another connection) means that a user has reconnected to the previous RDP session;
  • reason code 11 (User activity has initiated the disconnect) means that a user has clicked the Disconnect button in the start menu.

The event with the EventID 4778 in Windows -> Security log (A session was reconnected to a Window Station). A user has reconnected to an RDP session (a user is assigned a new LogonID).

The event with the EventID 4799 in “Windows -> Security” log (A session was disconnected from a Window Station). A user has been disconnected from an RDP session.

Logoff refers to the user logoff from the system. It is logged as the event with the EventID 23 (Remote Desktop Services: Session logoff succeeded) in “Applications and Services Logs -> Microsoft -> Windows -> TerminalServices-LocalSessionManager -> Operational”.

At the same time the event with the EventID 4634 (An account was logged off) appears in the Security log.

The event with the EventID 9009 (The Desktop Window Manager has exited with code <X>) in the System log means that a user has initiated logoff from the RDP session with both the window and the graphic shell of the user have been terminated.

Here is a short PowerShell script that lists the history of all RDP connections for the current day from the terminal RDS server logs. The resulting table shows the connection time, the client’s IP address and the remote user name (if necessary, you can include other LogonTypes to the report).

Get-EventLog -LogName Security -after (Get-date -hour 0 -minute 0 -second 0)| ?{(4624,4778) -contains $_.EventID -and $_.Message -match 'logon type:\s+(10)\s'}| %{
(new-object -Type PSObject -Property @{
TimeGenerated = $_.TimeGenerated
ClientIP = $_.Message -replace '(?smi).*Source Network Address:\s+([^\s]+)\s+.*','$1'
UserName = $_.Message -replace '(?smi).*Account Name:\s+([^\s]+)\s+.*','$1'
UserDomain = $_.Message -replace '(?smi).*Account Domain:\s+([^\s]+)\s+.*','$1'
LogonType = $_.Message -replace '(?smi).*Logon Type:\s+([^\s]+)\s+.*','$1'
})
} | sort TimeGenerated -Descending | Select TimeGenerated, ClientIP `
, @{N='Username';E={'{0}\{1}' -f $_.UserDomain,$_.UserName}} `
, @{N='LogType';E={
switch ($_.LogonType) {
2 {'Interactive - local logon'}
3 {'Network connection to shared folder)'}
4 {'Batch'}
5 {'Service'}
7 {'Unlock (after screensaver)'}
8 {'NetworkCleartext'}
9 {'NewCredentials (local impersonation process under existing connection)'}
10 {'RDP'}
11 {'CachedInteractive'}
default {"LogType Not Recognised: $($_.LogonType)"}
}
}}

Sometimes it can be more convenient to view and investigate RDP logs in the Excel table, so you can export any Windows events into a text file and import it in Excel. You can export the log from the Event Viewer GUI (only if the event logs are not cleared), from the command prompt:

WEVTUtil query-events Security > c:\ps\rdp_security_log.txt

Or like this:

get-winevent -logname "Microsoft-Windows-TerminalServices-LocalSessionManager/Operational" | Export-Csv c:\ps\rdp_connection_log.txt  -Encoding UTF8

You can display the list of current remote sessions on your RDS server using this command:

qwinsta

The command returns the session ID (ID), the name of user (USERNAME) and the session state (Active/Disconnect). It is convenient to use this command when you need to get the ID of the user RDP session in case shadow connection is used.

You can display the list of the running processes in the specific RDP session (the session ID is specified):

qprocess /id:5

Logs on an RDP client side are not quite informative, but you can check the history of RDP connections in the user’s registry.