isprime DOS in progress

Nathan Ollerenshaw chrome at
Fri Jan 23 23:42:13 UTC 2009

On 24/01/2009, at 6:46 AM, Steven Lisson wrote:

> Hi,
> I agree with seeing no traffic to/from but am still  
> seeing flows 'from'
> Regards,
> Steve

Hi Steve,

There is at least an iptables rule you can use to drop this specific  
query, assuming your nameservers run linux.

The bind-users mailing list suggested having the ISPs trace back the  
flows and find the networks emitting the spoofed packets, and have  
those networks implement BCP 38. While that's the 'right' solution  
(everyone should be doing ingress filtering, sure, impossible to argue  
against it), not every network out there is operated by people who  
give a damn.

This will work at least until the kiddies improve their scripts to  
query for names that actually exist.

On 24/01/2009, at 8:21 AM, Chris McDonald wrote:

> We [AS3491] null0'd the IP earlier.  Rest-of-world encouraged to do  
> the same :/

Good luck with that. Right now they're targetting ISPrime, and you've  
just made the DoS even more effective for them. With any luck, the  
rest of the world will follow suit and the bad guys win! yay! :)

Short of getting the rest of the world to properly implement ingress  
filtering (ha, ha), I think dropping the specific packets that  
generate the reflected traffic is good enough for now. The load on the  
reflectors is minimal.


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