slow scans?

[Anton Chuvakin <anton () chuvakin org>]

All,

This is a somewhat generic information query for methods to detect slow
(aka "low and slow")  port scans and network scans using IDS (or whatever
other means).

By slow scans I mean port probes occurring over the period of hours to
months (!) against the different destinations and even potentially from
different sources (both in the form of coordinated and spoofed scans).

The only resource I identified was the Spice/Spade from the Silicon
Defense site. References in
http://www.silicondefense.com/pptntext/Spice-JCS.pdf seem to be pretty
outdated and the detection methods are implied to be inferior to that of
Spice.

Also, the classic X packets in Y second to Z port/hosts seem to be pretty
useless for truly slow scans, such as those spanning days and weeks.
Plotting pictures of sequential port accesses seem to only reveal the
sequential scans from a single source against a single destination, which
are relatively easy to pick up. Anything more high tech?

And finally, does anybody really care? I know for sure that some folks do,
but I suspect their percentage is reeeally small. Is that so?

Thanks a lot for any tips, references and information pointers.

Best,
--
  Anton A. Chuvakin, Ph.D., GCIA
     http://www.chuvakin.org
   http://www.info-secure.org