DDoS attack

Mon Dec 9 20:32:01 UTC 2019

Hello,

you're forgetting if that was to be amplification, the source addresses would not be within Google or CloudFlare ranges (especially not CloudFlare, as they are not running a vulnerable recursor, and merely authoritative nameservers), the only possibility would be Google as in Google Cloud, with clueless people running open recursors that are prone to DNS(-SEC) reflection. It would pretty much be beyond the point using authoritative servers of parties such as CloudFlare as a) the scope of replies you will get is limited, b) they will high likely take a close look at your (forged) DNS queries and c) they will most certainly have limits in place defeating the entire point.

In any regard, <1 Gbps is pretty piss poor for an amplification attack too.

Cheers.
On 9 Dec 2019, 9:17 PM +0100, Filip Hruska <fhr at fhrnet.eu>, wrote:
> Hello,
>
> which attack protocol are seeing? I suspect you're seeing DNS based amplification or similar, in which case you can't really pinpoint the attack source...
>
> 800Mbps is not a whole lot of traffic - does it cause any disruptions to you? If the prefixes are not in use, I would suggest the use of RTBH (null routing / blackholing)
>
> Kind Regards,
> Filip Hruska
>
>
>
> > On 9 December 2019 9:07:35 pm GMT+01:00, "ahmed.dalaali at hrins.net" <ahmed.dalaali at hrins.net> wrote:
> > > Dear All,
> > >
> > > My network is being flooded with UDP packets, Denial of Service attack, soucing from Cloud flare and Google IP Addresses, with 200-300 mbps minimum traffic, the destination in my network are IP prefixes that is currnetly not used but still getting traffic with high volume.
> > > The traffic is being generated with high intervals between 10-30 Minutes for each time, maxing to 800 mbps
> > > When reached out cloudflare support, they mentioned that there services are running on Nat so they can’t pin out which server is attacking based on ip address alone, as a single IP has more than 5000 server behind it, providing 1 source IP and UDP source port, didn’t help either
> > > Any suggestions?
> > >
> > > Regards,
> > > Ahmed Dala Ali
>
> --
> Sent from my mobile device. Please excuse my brevity.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.nanog.org/pipermail/nanog/attachments/20191209/785d745b/attachment.html>