Summary
A fake FTP server was installed by the KIBUV.B worm on this port. This worm uses known security flaws to infect the system.
This machine may already be a 'zombi' used by crackers to perform distributed denial of service.
http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM_KIBUV.B&VSect=T
Solution
patch your system and run an antivirus
