TDM voice DOS

Charles N Wyble charles at
Tue Aug 16 16:57:31 UTC 2011

On 08/16/2011 11:46 AM, harbor235 wrote:
> Anyone been involved with TDM voice DOS attacks? My thoughts are that if the
> phone
> call originates as an IP call somewhere in the wild, then typical abuse
> security incident notifications may help
> in the interim.

Indeed. Though I suppose it depends on where they come from. Probably 
originate in various nasty neighborhoods of the net.

>   At least potentially identify through customer records or
> make them move on where they eventually slip up.


> If the abuse originates as IP what obligations do foreign service providers
> (friendly?) have to
> identify and mitigate?

Well I work at a very large shared hosting provider. Our upstream 
provider gets abuse complaints and a ticket lands in our queue telling 
us to clean up or the box gets dropped off the net (anywhere from 4 to 
48 hour warning window).

I'm guessing that most large service providers have similar procedures 
in place? Just hit up the abuse contacts for the IP range.  Doesn't 
matter where the destination is, what media etc. If it originates on an 
IP network/device, it can be dealt with that way.

However the bad guys probably aren't using the large providers, as they 
usually operate 24x7 abuse desks,  which means rapid ban hammering.  :)

>   How can the community respond to service providers
> who fail to
> clean up their customer base?

iptables -s x.x.x.x/8 -j DROP  (modify to your local site firewall drug 
of choice).

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