where to go to understand DDoS attack vector

Tue Aug 26 16:52:35 UTC 2014

On 08/26/2014 07:58 AM, Roland Dobbins wrote:
> On Aug 26, 2014, at 8:37 PM, John York <johny at griffintechnology.com> wrote:
>
>> In this case, 17 is both the protocol and port number. Confusing coincidence :)
> Not in this output which the OP sent to the list:
>
>> 8:33:58.482193 IP (tos 0x0, ttl 56, id 0, offset 0, flags [DF], proto UDP (17), length 29) x.x.x.x.2072 > x.x.x.x.27015: UDP, length 1
>>                 0x0000: 4500 001d 0000 4000 3811 088c cf9a 3b8c E..... at .8 <mailto:E..... at .8>.....;.
>>                 0x0010: 405e eebf 0818 6987 0009 10f8 4300 0000 @^....i.....C...
>>                 0x0020: 0000 0000 0000 0000 0000 0000 0000       ..............
>
>> 18:33:58.482193 IP (tos 0x0, ttl 56, id 0, offset 0, flags [DF], proto UDP (17), length 29) x.x.x.x.2072 > x.x.x.x.27015: UDP, length 1
>>                 0x0000: 4500 001d 0000 4000 3811 088c cf9a 3b8c E..... at .8 <mailto:E..... at .8>.....;.
>>                 0x0010: 405e eebf 0818 6987 0009 10f8 4300 0000 @^....i.....C...
>>                 0x0020: 0000 0000 0000 0000 0000 0000 0000       ..............
>> 18:33:58.484625 IP (tos 0x0, ttl 56, id 0, offset 0, flags [DF], proto UDP (17), length 29) x.x.x.x.2072 > x.x.x.x.27015: UDP, length 1
>>                 0x0000: 4500 001d 0000 4000 3811 088c cf9a 3b8c E..... at .8 <mailto:E..... at .8>.....;.
>>                 0x0010: 405e eebf 0818 6987 0009 10f8 4300 0000 @^....i.....C...
>>                 0x0020: 0000 0000 0000 0000 0000 0000 0000       ..............
>> 18:33:58.486137 IP (tos 0x0, ttl 56, id 0, offset 0, flags [DF], proto UDP (17), length 29) x.x.x.x.2072 > x.x.x.x.27015: UDP, length 1
>>                 0x0000: 4500 001d 0000 4000 3811 088c cf9a 3b8c E..... at .8 <mailto:E..... at .8>.....;.
>>                 0x0010: 405e eebf 0818 6987 0009 10f8 4300 0000 @^....i.....C...
>>                 0x0020: 0000 0000 0000 0000 0000 0000 0000       ..............
> Source port 2072, destination port 27015.

Been awhile since I got to dig into hex tcpdump but spent the time 
anyway. A UDP data segment that is 9 bytes long and only contains a "C" 
(0x43) ? And looks like to a Steam/Half-life (27015) gaming port. Not 
sure what the "C" is used for with those systems but guessing it's some 
sort of request?

--john

>
> ----------------------------------------------------------------------
> Roland Dobbins <rdobbins at arbor.net> // <http://www.arbornetworks.com>
>
>                     Equo ne credite, Teucri.
>
>      		   	  -- Laocoön
>