She got married in
    the mosque without her parents’ knowledge
Question

                Is secret nikkah is permissible? My friend
      went to mosque secretly from her parents and had a nikkah but there was only one witness
      for the nikkah. Is the nikkah valid. Please advise may god bless you.Thank you.
Praise be to Allah.There has to be a walee (guardian) and two witnesses to any 
  marriage, because of the hadeeth, “There is no marriage except with a walee” 
  and “Any woman who gets married without the knowledge of her walee, her 
  marriage is invalid.” Therefore this marriage contract must be renewed, 
  if her walee agrees to that, in the presence of two suitable witnesses. See 
  Question #2127.
And Allaah knows best.