Small Denial of Service in MobiLink Listener <= 10.0.1.3629
by Luigi Auriemma
e-mail: aluigi@autistici.org
web:    aluigi.org

MobiLink Listener is part of the Sybase SQL Anywhere package, more info
are available here:

  http://www.ianywhere.com/developer/product_manuals/sqlanywhere/0902/en/html/dbmsen9/00000044.htm

The dblsn.exe process which listens on UDP port 5001 can receive
packets of max 1024 bytes, packets greater than this size cause the
blocking of the listener service with a messagebox reporting the
following error:

  "A call to lsn_udp.dll failed with Windows Sockets error 10040"

When the admin acknoledges the message the listener will return to work
correctly.
This problem is reported only for thoroughness since I don't see a real
attack scenario.

For testing the bug is enough to use:

  udpsz SERVER 5001 1025

http://aluigi.org/testz/udpsz.zip