fix: check both target and subject fields, 4624 type 7 is now an unlock event, 4634 now allows type 7 for logoff/session change, added security log access check

Get-UserLogonActivity.ps1

@@ -100,6 +100,25 @@ Function Get-EventDataValue {
     Return [string]$Data.'#text'
 }
 
+Function Get-EventDataValueFromList {
+    Param(
+        [Parameter(Mandatory=$true)]
+        [xml]$EventXml,
+
+        [Parameter(Mandatory=$true)]
+        [string[]]$Names
+    )
+
+    ForEach ($Name in $Names) {
+        $Value = Get-EventDataValue -EventXml $EventXml -Name $Name
+        If (-not [string]::IsNullOrWhiteSpace($Value) -and $Value -ne '-') {
+            Return $Value
+        }
+    }
+
+    Return $null
+}
+
 Function Test-UserLogonActivityUser {
     Param(
         [AllowNull()]
@@ -131,6 +150,16 @@ Function Format-UserName {
     Return "${DomainName}\${UserName}"
 }
 
+Function Get-UserLogonActivitySecurityLogAccessError {
+    Try {
+        Get-WinEvent -ListLog Security -ErrorAction Stop | Out-Null
+        Return $null
+    }
+    Catch {
+        Return "Unable to read the Windows Security event log. Run PowerShell as administrator if access is denied. $($_.Exception.Message)"
+    }
+}
+
 Function ConvertTo-UserLogonActivity {
     Param(
         [Parameter(Mandatory=$true)]
@@ -138,18 +167,23 @@ Function ConvertTo-UserLogonActivity {
     )
 
     $EventXml = [xml]$Event.ToXml()
-    $UserName = Get-EventDataValue -EventXml $EventXml -Name 'TargetUserName'
-    $DomainName = Get-EventDataValue -EventXml $EventXml -Name 'TargetDomainName'
+    $UserName = Get-EventDataValueFromList -EventXml $EventXml -Names @('TargetUserName', 'SubjectUserName')
+    $DomainName = Get-EventDataValueFromList -EventXml $EventXml -Names @('TargetDomainName', 'SubjectDomainName')
     $LogonType = Get-EventDataValue -EventXml $EventXml -Name 'LogonType'
     $Activity = $null
 
     Switch ($Event.Id) {
         4624 {
-            If ($LogonType -notin @('2', '10', '11')) { Return $null }
-            $Activity = 'logon'
+            Switch ($LogonType) {
+                '2' { $Activity = 'logon' }
+                '7' { $Activity = 'unlock' }
+                '10' { $Activity = 'logon' }
+                '11' { $Activity = 'logon' }
+                Default { Return $null }
+            }
         }
         4634 {
-            If ($LogonType -notin @('2', '10', '11')) { Return $null }
+            If ($LogonType -notin @('2', '7', '10', '11')) { Return $null }
             $Activity = 'logoff'
         }
         4647 {
@@ -178,6 +212,12 @@ Function ConvertTo-UserLogonActivity {
     }
 }
 
+$SecurityLogAccessError = Get-UserLogonActivitySecurityLogAccessError
+If (-not [string]::IsNullOrWhiteSpace($SecurityLogAccessError)) {
+    Write-Error $SecurityLogAccessError
+    Exit 1
+}
+
 $Filter = @{
     LogName = 'Security'
     Id = @(4624, 4634, 4647, 4800, 4801)