Stopping ip range scans

jlewis at jlewis at
Mon Dec 29 14:49:21 UTC 2003

On Mon, 29 Dec 2003 william at wrote:

>  Recently (this year...) I've noticed increasing number of ip range scans 
> of various types that envolve one or more ports being probed for our
> entire ip blocks sequentially. At first I attributed all this to various 

What ports are being probed?  SOP for script kiddies for at least 10 years 
has been find a box you can hack root on, install a vulnerability scanner 
for the remote-root vulnerability d'jour, fire it up, and come back in a 
day or so to see what you've found.  Then hack the newly found vulnerable 
boxes, install the scanner on each of them, and repeat the process.  Some 
of these packages have done things like download the .com zone (back when 
F allowed this) and scan all NS's for bind vulnerabilities.  Others just 
pick a random IP and scan sequentially higher IPs.  More recently, some 
packages have combined the scanning and hacking.

If you don't want the scans, block everything you don't want at your
router.  Otherwise, just make sure your systems are up to date.  A common
OS with unpatched known remotely exploitable holes doesn't last long on an
unfiltered internet connection.

 Jon Lewis *jlewis at*|  I route
 Senior Network Engineer     |  therefore you are
 Atlantic Net                |  
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