Re: Filter NTP traffic by packet size?

[Jared Mauch <jared () puck nether net>]

On Feb 26, 2014, at 5:33 PM, Valdis.Kletnieks () vt edu wrote:

> On Wed, 26 Feb 2014 11:44:55 -0600, Brandon Galbraith said:
>
> > Blocking chargen at the edge doesn't seem to be outside of the realm of
> > possibilities.
>
> What systems are (a) still have chargen enabled and (b) common enough to make
> it a viable DDoS vector?  Just wondering if I need to go around and find
> users of mine that need to be smacked around with a large trout....

First, if you didn't see this excellent paper, check it out:

http://www.internetsociety.org/doc/amplification-hell-revisiting-network-protocols-ddos-abuse

a) Yes - printers and other devices have it.

b) yes.

I only ran the scan once, but had ~130k devices respond.

http://chargenscan.org/chargenip2asn.txt

- Jared