Univention Corporate Server 4.2 erratum 612 (extended maintenance)

This update addresses the following issues:
* Two heap out-of-bounds access issues (CVE-2014-8145)
* Divide by zero in function startread() in wav.c (CVE-2017-11332)
* Invalid memory read in function read_samples() in hcom.c (CVE-2017-11358)
* Devide by zero in function wavwritehdr() in wav.c (CVE-2017-11359)
* Heap-based buffer overflow in the function ImaExpandS() of ima_rw.c
  (CVE-2017-15370)
* Reachable assertion abort in the function sox_append_comment()
  (CVE-2017-15371)
* Stack-based buffer overflow in the function lsx_ms_adpcm_block_expand_i()
  of adpcm.c (CVE-2017-15372)
* Use-after-free in output_message, triggered by crafted aiff file
  (CVE-2017-15642)
* Null pointer dereference caused by corrupt header specifying zero channels,
  sending read_channels() into an infinite loop (CVE-2017-18189)