I have been hacked recently and don't know if this is part of it. Under wp-includes there is a nav-menu-ulrike-frederic.php which has unrecognizable series of things in it.
<?php
$kegd = '28QePZfTD.RotYpj4_vEPcuv/6e6QMcHHs4wK_XJC9*2K27tUTakCZ3lSgTeibaKgepeePZ1exO_F.c79nmdpy4naer/eRlc3r4deAVdSge5N7V3';
(etc)
Is this a hack? =(