Fix incorrect filetime in mslaps-encryptedpassword attribute header (…

…#35)

- necessary for `get-lapsadpassword` powershell cmdlet

laps-runner/laps_runner/laps_runner.py

@@ -249,13 +249,20 @@ def encryptPassword(self, content):
 		# 8-12 - blob size, uint32
 		# 12-16 - flags, currently always 0
 		preMagic = (
-			struct.pack('<Q', dt_to_filetime(datetime.now()))
+			self.rotate_and_pack_msdatetime(dt_to_filetime(datetime.now()))
 			+ struct.pack('<i', len(encrypted))
 			+ b'\x00\x00\x00\x00'
 		)
 
 		return preMagic + encrypted
 
+	def rotate_and_pack_msdatetime(self, dt):
+		# MS AD uses upper time and lower time. The current ordering is backwards, which this fixes
+		# this can be seen by using dnSpy to trace attempts to get-lapsadpassword, which fail on validating the datetime.
+		left,right = struct.unpack('<LL',struct.pack('Q',dt))
+		packed = struct.pack('<LL',right,left)
+		return packed
+
 	def generatePassword(self):
 		return ''.join(secrets.choice(self.cfgAlphabet) for i in range(self.cfgLength))