[VOIPSEC] Actual Attacks - UA handling

[Geoff Devine]

Mark Teicher writes:
> Even the media gateways seem to get shaken a bit when
> oversize RTP packets are sent.

Most media gateways use some sort of commodity high-density codec chip
like a TI Janus.  The most typical arrangement is to feed this
high-density codec packet interface with some variant of 10/100
Ethernet/MII interface.  These high density codec chips don't usually
have the internal RAM or spare MIPS to cope with a wirespeed denial of
service attack directed at a single chip.  If the vendor implementation
doesn't have some kind of traffic shaping elsewhere in the
implementation, it's pretty easy to kill one of these chips.  If you're
shaving cost on a commodity media gateway that only has a few T1
interfaces, you might overlook this.

Geoff