[HN Gopher] Record DDoS pummels site with once-unimaginable 7.3T...
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       Record DDoS pummels site with once-unimaginable 7.3Tbps of junk
       traffic
        
       Author : Brajeshwar
       Score  : 57 points
       Date   : 2025-06-21 12:56 UTC (10 hours ago)
        
 (HTM) web link (arstechnica.com)
 (TXT) w3m dump (arstechnica.com)
        
       | smokel wrote:
       | _> A total of 34,500 ports were targeted, indicating the
       | thoroughness and well-engineered nature of the attack._
       | 
       | How is that more complicated than a for-loop?
        
         | ukuina wrote:
         | Because it's a _distributed_ for loop?
        
           | lolinder wrote:
           | Not necessarily. It could be one for loop running on tens of
           | thousands of compromised IoT devices, with the only thing
           | distributed being the command that starts the loops.
        
             | saulpw wrote:
             | Sounds like you've never managed tens of thousands of nodes
             | in a distributed system. It's not trivial.
        
               | jjtheblunt wrote:
               | (elixir / otp says "hold my beer")
        
               | luckylion wrote:
               | What would making a C&C server for a botnet hard? It's
               | not like you need to carefully coordinate all those
               | clients to hit precise timings, you just tell them who to
               | target and let them rip, don't you?
        
               | PcChip wrote:
               | Nothing. I did it with IRC servers in the late 90s when I
               | was a dumb kid in high school
        
         | blitq wrote:
         | It's not :)
        
         | monster_truck wrote:
         | You can't just spray every port blindly if you are maximally
         | trying to disrupt, there is nuance to it.
        
           | lolinder wrote:
           | Right. So why does the fact that they targeted 34,500 ports
           | show it was a well-engineered attack? By itself it's just
           | evidence that they know how to iterate over ports. Coupled
           | with the data size (7.3Tbps) we know they had an enormous
           | botnet. None of this points to a well-engineered attack, it
           | just means that lousy IoT has made botnets incredibly cheap.
           | 
           | A well-engineered attack would not draw headlines for its
           | scale because it would take down its target without breaking
           | any records.
        
             | motorest wrote:
             | > A well-engineered attack would not draw headlines for its
             | scale because it would take down its target without
             | breaking any records.
             | 
             | You don't hear much about DDoS that are either comparable
             | in size or bring down targets. How do you explain why this
             | one made the news in spite of not having met your arbitrary
             | and personal bar?
        
               | lolinder wrote:
               | Like I said: it broke records for data throughput. It
               | doesn't hurt that Cloudflare has an interest in
               | publicizing the size of the DDoS attacks it fights off.
               | 
               | > in spite of not having met your arbitrary and personal
               | bar?
               | 
               | I'm not sure what you mean by this. I didn't establish
               | any sort of bar for what sorts of DDoS should get
               | headlines, I'm just agreeing with OP that that line in
               | the article doesn't make any sense. There may be other
               | reasons to believe this attack was well-engineered but
               | the article doesn't get into them.
        
       | balanc wrote:
       | Doesn't Cloudflare have every incentive to inflate the bandwidth
       | of the attack they have successfully mitigated?
       | 
       | And yes I know that there are Cloudflare employees here so spare
       | me with your pinky swears.
        
         | x2tyfi wrote:
         | Couldn't this logic apply to basically every internal metric
         | across every company?
        
         | move-on-by wrote:
         | A couple months ago Brain Krebs, who uses Google's Project
         | Shield, wrote of a very similar attack. 6.3 terabits, all UDP,
         | less then a minute.
         | 
         | https://krebsonsecurity.com/2025/05/krebsonsecurity-hit-with...
        
       | ksec wrote:
       | If I dont want my user to have Cloudflare captcha or for example
       | captcha dont work on my Safari 18.5 running on OpenCore Patcher
       | MacBook 2015. What other options have I got?
        
         | nemathod wrote:
         | GRE-Tunnel
        
           | VladVladikoff wrote:
           | I'm confused what this would accomplish? Do GRE tunnels drop
           | UDP packets or something?
        
             | firebird84 wrote:
             | You make a contract with a company that does layer 3 ddos
             | protection, you advertise a route including their AS on a
             | subset of your prefixes and they route to you over a GRE
             | tunnel.
        
               | VladVladikoff wrote:
               | Sorry for the noob questions here but why couldn't you
               | just firewall? ie only allow traffic forwarded from the
               | DDOS proxy?
        
               | immibis wrote:
               | With these services the forwarding happens at a lower
               | level. The traffic doesn't come from them - the source
               | address is whoever actually sent the traffic. And the
               | destination address is you, but the Internet thinks they
               | are hosting you. They can't just forward the same packets
               | to you because they'd just go back to the DDoS provider
               | because that's where "you" "are". So they put the packets
               | inside other packets and send them to you on a different
               | address.
               | 
               | I suppose they could rewrite the destination to be your
               | real address, and then send them to you without extra
               | layers; you wouldn't get to know what the original
               | destination address was; maybe if you only have one, it
               | doesn't matter.
        
         | VladVladikoff wrote:
         | Most websites don't need DDOS protection. Many websites which
         | use Cloudflare to block basic bot vulnerability scanning. You
         | could block this type of traffic with other methods; ja3/ja4,
         | Ip to ASN & ASN filtering, etc.
        
           | esseph wrote:
           | Your first line is wrong.
           | 
           | While it may not impact your site, it does impact your
           | hosting provider. As their costs go up, your costs go up.
           | Anything on the Internet at this point needs DDoS / scraping
           | protection. If may not drop your service, but your ISP or
           | upstreams may blackhole your route.
           | 
           | The "old web" (current web) was largely based on an open
           | exchange of information.
           | 
           | The "new web", post AI bot scraping, is taking its place.
           | Websites are getting paywalls. Advertising revenue is
           | plummeting. Hosting providers are getting decimated by the
           | massive shift in bandwidth demand and impact to systems
           | scraped by the bots.
        
             | VladVladikoff wrote:
             | I guess my products fall into a niche that doesn't seem to
             | attract AI crawlers. I've seen only a few and they haven't
             | been too aggressive. I mean they ignore typical crawl rate
             | limits defined in robots.txt but account for maybe only
             | 1-2% of my overall traffic.
        
             | immibis wrote:
             | DDoS and AI are mostly unrelated. Sure, AI companies are
             | running low-quality scrapers, but they don't cause nearly
             | as much traffic as a DDoS. They might cause as much CPU
             | load as a DDoS, which is an application-level problem.
        
         | zzzeek wrote:
         | dont piss off any nation-states that would want to take your
         | site down, should help
        
           | petee wrote:
           | Fwiw, i have a site with nearly zero content or users;
           | randomly it got ddos'd one day, and never happened again. I
           | think the reasons for a ddos can be wide ranging, from just
           | testing, to nation state, to someone is unhappy with your
           | font choice
        
             | inetknght wrote:
             | > _to someone is unhappy with your font choice_
             | 
             |  _Everyone_ hates when I set my app 's fonts to courier
             | size 8.
        
           | esseph wrote:
           | An 11 year old with a discord account and a stolen credit
           | card can now rent massive capabilities that can take
           | (smaller, limited peered) entire countries offline for brief
           | periods these days.
        
         | immibis wrote:
         | The simplest is to just wait until the attacker is bored,
         | and/or daddy's credit card runs out.
         | 
         | If you aren't doing any business, or not much business, through
         | your site, this can be fine. Your hosting provider may either
         | choose to let your server be overwhelmed with as many packets
         | as its pipe can fit, or it may need to protect its network by
         | discarding traffic to your IP address upstream of itself. It's
         | probably a good idea to reach out to your hosting provider and
         | let them know you're getting DDoSed. Even if they can't do
         | anything about it (though there's a chance they can) they'll
         | hopefully appreciate the heads up.
         | 
         | True story: I ran a Pixelflut client for 38C3 from a Netcup
         | server in Nuremberg (this somehow had better performance than
         | running it on my tablet _at the physical location_ ) and they
         | somehow thought 38C3 was DDoSing me and "helpfully" blackholed
         | traffic between 38C3 and my server.
         | 
         | ---
         | 
         | It's important to stop thinking of DDoS as some magic hammer of
         | Thor that you can't do anything about. DDoS packets, like all
         | other packets, have source and destination addresses and flow
         | through routers and links.
         | 
         | When Cloudflare receives a 7-terabit DDoS, they aren't
         | receiving 7 terabits through one link. Cloudflare operates a
         | huge number of locations that pretend to be one coherent
         | network. So they're receiving 100 gigabits in London, 100
         | gigabits in Frankfurt, 200 gigabits in NYC, etc. Their network
         | architecture pretends like it's delivering all these packets to
         | their destination addresses, but really, each location has its
         | own completely different set of servers that all have the same
         | addresses. (This is called anycast.) Each individual packet
         | sender is only sending packets to the nearest Cloudflare node,
         | where they're getting discarded. Likely, no individual node is
         | overloaded by this, but when you aggregate the statistics from
         | all of them, it adds up to a large amount of traffic. This is
         | by the nature of a DDoS - it's devices all over the world
         | attacking you, which means they're all coming by different
         | routes.
         | 
         | It's similar with hosting providers too, at least the big ones.
         | Suppose you're on Hetzner:
         | https://www.hetzner.com/unternehmen/rechenzentrum/ . They're
         | not getting a terabit against your server through one link -
         | they're getting 100Gbps through DE-CIX Frankfurt, 10Gbps
         | through AMS-IX, 50Gbps through Telia in Nuremburg, 50Gbps
         | through Telia in Helsinki, 50Gbps through Core-Backbone, etc.
         | 
         | If they deploy a routing rule to the router on their end of
         | each of those links, which says to discard packets where the
         | destination address is yours, they can protect their network.
         | Your site will still be down, of course.
         | 
         | If one of their pipes does get overloaded (say their full
         | 10Gbps from Baltnet in Frankfurt), they can reach out to that
         | network (pretty much every serious network on the internet has
         | a network operations center, reachable 24/7 by phone) and
         | Baltnet will track it down further and block the traffic even
         | closer to its source (or at a wider part of their network).
         | 
         | If you're lucky and the DDoS traffic is just coming from a few
         | "directions", users whose packets happen to come via a
         | different direction may still be able to access your site.
         | 
         | Suppose you're on Uncle Tom's Tiny Hosting Company Ltd (not
         | real), they're certainly not the scale of Hetzner, and they
         | only have a 10Gbps pipe between them and their ISP which is
         | easily filled by a single attack. They'll have to contact their
         | ISP to block traffic to your server so that the rest can get
         | through, and their ISP will do the above stuff.
         | 
         | None of this information will keep your site up during a DDoS,
         | I just want to show you there's a depth to this DDoS thing and
         | this Internet thing and it's not just magic.
        
       | encom wrote:
       | So this "article" "source" is Cloudflare, claiming Cloudflare
       | blocked some super duper mega attack, but gives zero verifiable
       | detail about any of it.
       | 
       | Now I hate Cloudflare with a passion, but even setting that
       | aside, this is journalistic malpractice - it's basically a
       | sponsored post. I was going to say I expected better from Ars
       | Technica, but their glory days are long gone.
        
         | gundmc wrote:
         | Why do you hate Cloudflare so passionately?
        
           | immibis wrote:
           | There are many reasons Cloudflare should be hated. The main
           | one is that their goal is to centralize the Internet. A
           | secondary one is all those bloody captchas. A tertiary one is
           | that they often block Tor, even if you pass a captcha. Yes,
           | it's configurable, but their recommended settings are the
           | ones that help break the internet.
           | 
           | However in this case I think we can rely on them to tell us
           | what they did. If they say they got a 7.3 Tbps UDP DDoS,
           | chances are good they actually did.
        
         | greggsy wrote:
         | How is CF not a valid primary source?
         | 
         | They literally are a DDoS mitigation service.
        
       | esafak wrote:
       | Who's doing this and why?
        
       | ChrisArchitect wrote:
       | [dupe] discussion on source:
       | https://news.ycombinator.com/item?id=44330585
        
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       (page generated 2025-06-21 23:01 UTC)