[HN Gopher] Belgian ISP under 250 Gbps DDoS for days on end
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       Belgian ISP under 250 Gbps DDoS for days on end
        
       Author : laurensr
       Score  : 230 points
       Date   : 2021-09-18 18:57 UTC (4 hours ago)
        
 (HTM) web link (issues.edpnet.be)
 (TXT) w3m dump (issues.edpnet.be)
        
       | s800 wrote:
       | I got hit with a ~40Gbps DDoS last week. These attacks are on the
       | rise. Some responses to folks above: Success working with
       | upstreams is quite varied. Some care, some don't, and it can be
       | difficult to get to folks that can help- even if their networks
       | are impacted as well. Some carriers immediately turn this into a
       | sales opp. - buy more bandwidth, buy more services.
       | 
       | In our case it was based on DNS reflection from a large number of
       | hosts. I've contacted the top sources (ISPs hosting the largest
       | number of attackers) and provided IPs and timestamps. I've
       | received zero responses.
       | 
       | Geo-based approaches yielded no helpful reduction in source
       | traffic.
       | 
       | Also, during this event we discovered an upstream of ours had
       | misconfigured our realtime blackhole capability. As a result, I'm
       | going to add recurring testing for this capability and burn a
       | couple IPs to make sure upstreams are listening to our rtbh
       | announcements.
       | 
       | Very concerned about the recent microtik CVE, as that is going to
       | make for some very large botnets.
       | 
       | Personally this all is very disappointing because it creates an
       | incentive to centralize / de-distribute applications to a few
       | extremely large infrastructure providers who can survive an
       | attack of these magnitudes.
        
         | pilsetnieks wrote:
         | Can you give more detail on what you mean by the "recent
         | Mikrotik CVE?" As far as I understood, the recent botnet was
         | utilizing devices still unpatched since the original issue
         | (2018?), as well as credentials gathered then even for patched
         | devices that were affected but passwords weren't rotated.
        
         | alcover wrote:
         | I fail to understand how DNS reflection attacks are possible.
         | Isn't it in the interest of any ISP to block outgoing spoofed
         | IP packets ? So as not to be accused of letting those attacks
         | originate from them ?
        
           | spc476 wrote:
           | I'm no sure how things are now, but 15 years ago (back when I
           | was doing network admin type stuff), most routers did
           | destination routing in hardware, source routing hit the CPU
           | and was thus, very slow. I think that was the primary reason
           | not to do that back then---perhaps it's still the case now?
        
           | kortilla wrote:
           | The ISP originating the spoofed packets isn't apparent to the
           | person receiving the attack. The source is spoofed to the
           | victim's address so neither the DNS operator nor the victim
           | can see where the spoofed packets originated.
        
             | alcover wrote:
             | I know. But one layer below, there's still a chain linking
             | back to the origin ISP. The DNS operator can ask his own
             | ISP about it.
             | 
             | (Also, to people down-voting a genuine _question_ ? wth..)
        
               | codexon wrote:
               | The mac addresses on the ethernet layer are rewritten at
               | each hop. You would only see the mac address of the
               | router your router is connected to, not a chain linking
               | back to the origin.
        
               | javajosh wrote:
               | Anecdotally I've noticed bot-like behavior on HN down-
               | voting posts almost immediately, before a human could
               | have read them. This is followed, typically, by a
               | correction over a few minutes and then regular up- (or
               | down-) voting resumes. I can imagine that HN is subjected
               | to quite a lot of novel attacks of this nature, and I
               | don't think it's in anyone's interest that they broadcast
               | the details of it. My advice: be patient and take
               | downvotes with a big grain of salt. They may not mean
               | what you think they mean.
        
           | toast0 wrote:
           | If you're thinking of residential ISPs which own the IPs that
           | their customers use, it's mostly pretty simple to prevent
           | spoofing (or at least, prevent spoofing outside their address
           | range), but once you get customers that can bring their own
           | IPs, it can be more cumbersome and the default is to not
           | care.
           | 
           | There are, of course, proposals and protocols to make things
           | better, but not caring is easier, and strict enforcement is
           | hard, especially as the bandwidth goes up.
           | 
           | There's also enough ISPs that don't do egress filtering that
           | name and shame isn't effective, and anyway, what am I going
           | to do if I'm connected to an ISP that doesn't filter? I have
           | exactly one meaningful offer of connectivity, so that's the
           | one I've accepted, regardless of its merits. Many ISPs have a
           | similar hold on customers.
        
             | alcover wrote:
             | Thanks.
             | 
             |  _> but once you get customers that can bring their own IPs
             | (...)_
             | 
             | You know these IPs though, since you route to your
             | customer. So you could drop the offending packets. (I may
             | be getting over my head here).
        
               | vgb2k18 wrote:
               | > I may be getting over my head here)
               | 
               | It may be so, however my own need for clarification was
               | the same as yours. If ISP xyz operates a /16 ip block,
               | and only forwards source packets from its /16... Then, I
               | guess, my question: how do spoofed packers usually travel
               | past their first hops on their route to the target?
               | 
               | [edit] after-thought: I imagine attackers might easily
               | spoof their source as any of their ISPs /16 or /8. Feels
               | like that's not entire story here though.
        
               | toast0 wrote:
               | The routing need not be symmetric. If I've got two /24s
               | and two ISPs, maybe I advertise each /24 on only one ISP,
               | for traffic engineering purposes (I want to steer some of
               | my clients to send through one ISP and some clients to
               | send through another), but that doesn't mean I want or
               | need to send the return traffic back through the same way
               | it came in.
               | 
               | Also, the routing/BGP configuration is often separate
               | from the filtering config, so making sure things are
               | synchronized can cause problems.
               | 
               | It's far less time intensive as an ISP to just not filter
               | once it starts getting complex. After all, you don't get
               | a lot of customer service calls when you let ill-advised
               | packets through, but you do get calls when you break
               | things by dropping packets your clients were authorized
               | to send.
        
           | codexon wrote:
           | Blocking outgoing spoofed packets requires time and money.
           | 
           | No carrier will shut down an ISP paying them 100k/month just
           | because of some spoofed traffic.
        
         | CircleSpokes wrote:
         | DNS based amplification has been very popular for many years
         | now. By this point if a DNS resolver is still being used by
         | amplification no email or contacting the ISP will do anything
         | as they have received many other similar emails.
        
           | flatiron wrote:
           | Dns is so broken in many different ways. It's crazy it's
           | still the back bone of the internet when it's insecure awful
           | nonsense. It's just ingrained.
        
         | temptemptemp111 wrote:
         | What is the lowest level hardware that can help defend against
         | DDoS on the backbone level? Or is that not a thing?
        
       | vadfa wrote:
       | A 250 Gbps attack is bringing an ISP down? How is this possible
       | in the age of 1 Gbps connections in every home?
        
         | BenjiWiebe wrote:
         | 50 1Gbps connections usually peak at less than 50Gbps.
         | Depending on your demographic and area, it can be a lot less.
         | 
         | 250 Gbps will service much more than 250 1Gbps connections.
         | 
         | Also, not nearly every ISP offers 1 Gbps to all their
         | customers. Some ISPs don't offer it at all.
        
           | tyingq wrote:
           | There's also things like local Netflix/Google/etc caching
           | boxes where you can serve downsteam traffic without touching
           | your upstream as much.
        
         | KindOne wrote:
         | They seem to only offer 20Mbps - 500Mbps.
         | 
         | https://www.edpnet.be/nl/thuis/internet.html
         | 
         | https://www.edpnet.be/nl/business/internet.html
        
           | laurensr wrote:
           | They are mainly offering VDSL2 connections over phone lines.
           | They also offer Fiber over a monopolist's (called Proximus)
           | GPON infrastructure, but the rollout of that GPON network is
           | still in early stages. However, that monopolist has pledged
           | to accelerate that rollout in light of the increasing work-
           | from-home statistics following the pandemic.
           | 
           | https://www.proximus.com/news/2020/20201208-proximus-
           | brings-...
        
         | NullPrefix wrote:
         | overselling
        
         | MeinBlutIstBlau wrote:
         | Just because everyone has 1Gbps doesn't mean if everyone tried
         | downloading something they'd get it. The internet is tunneled
         | through a system where the more people are on it, the more
         | likely that the bandwidth entirely gets used up. It's literally
         | like the phone systems back in the day where if everyone picked
         | up the phone, not everyone would get a dial tone.
        
         | storyinmemo wrote:
         | It's like a large city in a way. Most of your roads are local,
         | and so is most of your traffic. You try to distribute load and
         | makes trips as short as possible. For a city its grocery stores
         | in neighborhoods.
         | 
         | For an ISP, they do this by peering locally with major
         | providers. Google, Twitter, Facebook, Netflix, etc. all have
         | very large networks and will openly connect at Meet Me points
         | in open and private internet exchange sites as will CDN
         | providers.
         | https://en.wikipedia.org/wiki/Internet_exchange_point. Some
         | providers such as Google and Netflix will even install local
         | caching servers that you can reach from your network if you
         | have enough traffic. As a small ISP, you try to take advantage
         | of all of that.
         | 
         | Your option of last resort is the Tier 1 upstream provider.
         | That's for anything where you can't get to it via local transit
         | peering. This should be a smaller percentage of your traffic
         | and it costs more than peering arrangements. The nature of a
         | DDOS is going to fill that smallest and most expensive
         | connection that provides the filler access to the majority of
         | the world but doesn't handle the majority of the traffic.
         | 
         | Even as a hosting provider, it doesn't have to be overselling.
         | If you have 250 1Gbps customers and 250 Gbps of bandwidth,
         | you'll still be useless in the face of 250 Gbps of junk
         | traffic. Pick a random packet and tell me what should decide if
         | it is dropped is something that has to be determined upstream
         | of the saturated link.
         | 
         | EDPnet looks pretty well-connected too:
         | https://bgp.he.net/AS9031#_ix
        
       | pt_PT_guy wrote:
       | and no one accountable :-)
        
       | forty wrote:
       | Why are the people doing those attacks doing them? Ransom? Or are
       | they just doing that to prove and advertise/demo their capacity
       | to harm?
        
       | tigerlily wrote:
       | How can I check my home network for signs I have any devices
       | participating in a botnet?
        
         | mfkp wrote:
         | Generally large spikes in upload data usage is the best
         | indicator. Many consumer grade routers are starting to build in
         | per-device bandwidth usage, which helps narrow down the
         | culprit.
        
         | system2 wrote:
         | Invest in something like a cheap sonicwall. Without bunch of
         | licenses, it can still show you all the traffic information and
         | act as a very powerful firewall with all types of blocking. You
         | can search "sonicwall soho".
         | 
         | If you don't want to invest, you can also use pfsense. You can
         | use an old computer to turn it into a perfect firewall.
        
           | antattack wrote:
           | I used both pfsense, opnsense and none had good facilities to
           | keep track where your packets are going.
        
       | ineedasername wrote:
       | I'm very much not a network engineer, but I'd like to understand
       | the magnitude of this issue because my intuition _is wrong_ :
       | 
       | 250 Gbps seems like it would definitely be a lot for a server or
       | website but it also seem like a drop in the bucket for an ISP
       | providing broadband for many customers.
       | 
       |  _Clearly I 'm wrong_ because it is an issue here. I'd like to
       | understand _why_ I 'm wrong, and I hope that here, on HN, that's
       | taken in the spirit of curiosity intended and not negativism.
       | 
       | So, what am I missing? Maybe Belgian broadband is lower capacity
       | than what I'm used to in a US metropolitan area? Maybe this
       | particular ISP served a population too small to have a... um...
       | "fat pipe"? I'd like to understand.
        
         | xhrpost wrote:
         | 250Gbps is still a lot of bandwidth for a network even today.
         | An enterprise ISP like Verizon or Spectrum may have less of a
         | capacity issue with it but for many other networks this is a
         | lot.
         | 
         | Quick example, though not an ISP, but the entire Internet
         | archive operates on 60Gbps of bandwidth. So an attack of 250
         | would be quite a problem.
         | 
         | http://blog.archive.org/2020/05/11/thank-you-for-helping-us-...
        
           | ineedasername wrote:
           | _the entire Internet archive operates on 60Gbps of bandwidth_
           | 
           | Wow, yes, that definitely puts the magnitude of this into
           | perspective. Thank you.
        
           | Groxx wrote:
           | Though that's a substantial amount of traffic: isn't this
           | currently going through one ISP, which (I would hope) has
           | _many_ more customers than just archive.org?  "top 160 site"
           | is significant, but still minuscule compared to all internet
           | traffic.
        
         | Hikikomori wrote:
         | An ISP has two types of edge connections where ddos traffic
         | comes into their network. Private peering where they are
         | directly connected to their neighbor in one or more locations,
         | typically neither party pays for traffic, can be 1 to 100G
         | interfaces and multiple of them. Second type is transit,
         | smaller or mid sized buys it from larger ISPs and pay for
         | traffic. Everything that does not go directly to a peer
         | mentioned before goes over this connection. Can also be very
         | different in size.
         | 
         | You can just add upp all edge Links and know their theoretical
         | limit, but most of the ddos traffic likely comes from Asia and
         | it's unlikely that they peer directly with those ISPs. So most
         | of the traffic will go over transit, but the larger ISP likely
         | has an automated system that handles volumetric attacks. So if
         | there's any impact it will be on transit mostly affecting
         | traffic to/from outside of Europe. 250 might be a lot for this
         | ISP, but they might also have a lot more transit headroom, or
         | it light be handled by their transit provider. Who knows.
        
           | ineedasername wrote:
           | As an outsider to network topology that's fascinating to
           | understand. Thanks for explaining.
           | 
           | If you don't mind going further, how does an ISP (or anti-
           | DDoS services) mitigate something like this without incurring
           | even more overhead to examine the traffic & not route it
           | onwards? Just a flat block against the sources, or something
           | more sophisticated?
        
             | Hikikomori wrote:
             | Haven't done much traditional networking for a few years so
             | my knowledge is not that current.
             | 
             | They use bgp flowspec to send out filter lists using the
             | bgp protocol to routers, essentially a long list of ACL
             | rules with srcip dstip dstport. These routers can filter
             | any amount of traffic it gets in hardware, so as long as
             | your upstream (edge transit or peering links) are not full
             | you won't even notice the ddos.
             | 
             | But you need something to analyse traffic that can
             | understand which traffic is ddos and what is normal. We
             | used devices from Arbor which are basically regular x86
             | servers. These devices also received netflow so whenever a
             | ddos target received a lot of weird traffic (lots of DNS
             | for example) it was configured to redirect all traffic for
             | that IP to itself where it could gain a better
             | understanding than what you can from netflow and either
             | filtered it locally or sent out flowspec updates to filter
             | it on routers. You could also enable this manually for non-
             | volumetric ddos and do some filtering, but it's hard to do
             | if it's encrypted and if they are abusing some http call
             | that is just expensive to handle for the servers.
        
             | toast0 wrote:
             | ISP mitigation is usually simple. Figure out what the
             | destination of the attack traffic is and null route[1]
             | that, pushing those null routes upstream where possible. If
             | the destination IPs for the abuse are too diffuse and/or
             | the upstream won't do it on their routers where they
             | presumably have more capacity to drop than to forward to
             | you, you're still limited by your connection bandwidth on
             | the connections the abuse is flowing. Depending on the use
             | case, sometimes you can do pretty well by cycling your
             | legitimate traffic across a large block of IPs faster than
             | the abusers can cycle their abuse traffic, but it depends
             | on relationships and APIs to control null routing of your
             | upstreams. More sophisticated things like only block
             | traffic to/from port X, or throttling rather than blocking
             | aren't generally available (but would often be super
             | helpful if they were).
             | 
             | Anti-DDoS services are quite a bit different, they
             | generally have obscene bandwidth, and BGP advertise your
             | attacked IPs, so they can get the traffic, then they
             | "scrub" the traffic and provide it back to you over a
             | tunnel (or something). Scrubbing can be relatively simple
             | stuff like rate limiting UDP and especially fragmented UDP
             | (which is usually stuff coming from reflection attacks) or
             | more complex stuff like looking at TCP options to determine
             | good vs bad traffic and only letting good traffic through,
             | or tracking TCP SYNs and only letting retries through,
             | plenty of other stuff with TCP state machines (or half
             | state machines, if they're only seeing the incoming traffic
             | and not the outgoing traffic). Oh, and they usually charge
             | you gobs of money.
             | 
             | [1] if destination == IP, drop packet
        
         | bstpierre wrote:
         | I don't know anything about this particular isp or attack, but
         | if that 250 gbps is aimed at specific parts of their
         | infrastructure that are not designed for this much load, it's
         | likely to saturate individual links, servers, and/or network
         | gear.
         | 
         | Their announcement said "all of our services", so this could be
         | anything from their authoritative/recursive dns to monitoring
         | or billing servers to specific routing nodes.
         | 
         | So even if they had nice fat 100G pipes coming in, and those
         | pipes weren't saturated, a ddos of this size with a mix of
         | vectors can be debilitating on enough discrete pieces of
         | infrastructure that the isp is effectively "down" for many end
         | users.
         | 
         | (Again I am only speaking generally with guesses about what
         | _might_ be going on at this isp. I'm also not a network
         | engineer but I do write code for network gear that does anti
         | ddos stuff.)
        
         | perlgeek wrote:
         | ISPs have a very decentralized network, that is, they have
         | routers in a lot of places.
         | 
         | If you sum up the available traffic capacity, you get a number
         | that's far bigger than 250 Gbit/s.
         | 
         | But that's not the right comparison to make. Much of that DDoS
         | traffic goes through multiple of the ISP's routers, and if
         | you're doing just a numbers comparison, you'd have to multiply
         | the attack rate by the (average) number of hops.
         | 
         | But things are even more complicated in reality: many smaller
         | links will have only 10Gbit/s or 20Gbit/s or 40Gbit/s capacity
         | (or maybe even 1G), and saturating them not only causes
         | increased latency, but also routing the traffic around causes
         | more overall load on the network.
         | 
         | Then there are management systems behind firewalls, and if you
         | DDoS them, it's typically the firewalls that give out first.
         | 
         | Finally, customers don't get the full throughput internally
         | available to an ISP; if you DDoS a customer's IP, their link
         | will be saturated, even if the ISP itself has plenty to spare.
         | 
         | (Not a network engineer myself, but working closely with some).
        
           | Groxx wrote:
           | Wouldn't that all be true of normal web traffic too,
           | presumably already capable of rates beyond 250Gbps? Though
           | they may not have that much free headroom on top of normal
           | traffic.
        
       | ericbarrett wrote:
       | > EDIT 16/09/2021 10:12*: During the night we had two more
       | attacks. We are working with the authorities, who have confirmed
       | they are looking into it and are doing everything in their power
       | to find the responsible individuals. We were contacted by an
       | individual who verified he was behind the attacks, asking for a
       | ransom.
       | 
       | Roughly how many criminal groups are active in DDoS ransoms (as
       | opposed to data crimes, like cryptolockers and exfiltration)? How
       | common is this nowadays? Clearly it happens, but I've no idea the
       | general scale of the problem in 2021.
        
         | masklinn wrote:
         | > Roughly how many criminal groups are active in DDoS ransoms
         | 
         | These days there are groups providing ddos as a service. They
         | control huge iot botnets and for a sum they'll point whatever
         | fraction you pay for to whatever target you want.
        
           | ericbarrett wrote:
           | Put more concretely, how many can front 100+ Gbps? E.g. 2-3,
           | or dozens, hundreds, any teenager, etc.
        
             | sva_ wrote:
             | Depends what kind of attack they use. A few years back,
             | reflection attacks were all the rage, and it was cheap as
             | fuck. But I can't say how many Gbps they delivered.
             | 
             | They'd usually market this as "stresstest" service, and you
             | could pay by Paypal etc. Curiously they were all behind a
             | Cloudflare-anti-DDoS wall. I still wonder if Cloudflare
             | knew/knows about them, probably good for their business.
        
       | pstuart wrote:
       | I'm assuming that eBPF would be a potent tool for dealing with
       | this, and it looks like CloudFlare agrees:
       | https://blog.cloudflare.com/l4drop-xdp-ebpf-based-ddos-mitig...
        
       | stingraycharles wrote:
       | Since this is HN, it's 2021 and DDoS'es are still a thing: why
       | are they still a thing? Is there some fundamental "anonymity" to
       | the Internet that makes it impossible to structurally prevent
       | DDoS attacks? Apart from CloudFlare-like approaches, are there
       | any R&D in the pipeline that may kill this type of attack once
       | and for all?
       | 
       | To me it's incredibly infuriating to see the damage that still
       | happens with these extremely simple techniques. Will it ever end?
       | 
       | Edit: to elaborate, I know that there are tons of insecure
       | Internet devices and whatnot. I'm more interested in standards,
       | and core protocol improvements that can fundamentally rid the
       | world of these types of attacks.
        
         | ev1 wrote:
         | It isn't anonymity. It's insecurity. Until you fix the human
         | factor, bad code, weak passwords, shitty programming practices
         | and minimum outsourcing to the worst vendors.
        
         | foobiekr wrote:
         | DDOS events typically use distributed botnets. Unless you
         | analyze the CNC you're probably asking for wide deployment of
         | acls (flow spec or otherwise); and such agreements happen
         | occasionally, as they operationally brutal but are slow
         | (otherwise they would be subject to abuse).
         | 
         | You, right now, may be participating in a DDOS attack without
         | knowing it. Should your ISP cut you off based on information
         | from some Belgian ISP?
        
         | nine_k wrote:
         | A DDoS attack is indistinguishable from a huge legitimate
         | success. See Slashdot effect [1].
         | 
         | The very problem of a DDoS attack stems from that (1) each
         | request is a small, fully legitimate request and (2) there are
         | too many of them, coming from too many sources for filtering to
         | be efficient. It is also mixed with indistinguishable non-
         | attack requests by your normal customers.
         | 
         | So no, even the best authentication would help little.
         | 
         | [1]: https://en.wikipedia.org/wiki/Slashdot_effect
        
         | spenczar5 wrote:
         | DDoSes come from asymmetries in the difficulty of making a
         | request and providing a response.
         | 
         | For example, a classic is the SYN flood. In this, the attacker
         | makes many requests to open TCP connections (with a SYN packet)
         | but does none of the rest of the handshaking. The server does
         | the initial bookkeeping for setting up TCP connections, before
         | eventually timing out and freeing the resources. The SYN
         | packets are very cheap and easy to form (and the attacker can
         | immediately free all the resources after firing them away), but
         | the connection state information is a little bigger. This
         | asymmetry builds up, making the server overloaded.
         | 
         | I believe that asymmetries in resource consumption are, at some
         | point, unavoidable.
         | 
         | You also asked:
         | 
         | > are there any R&D in the pipeline that may kill this type of
         | attack once and for all?
         | 
         | Note that DDoS attacks are a _class_ of attacks. They 're a
         | description for a broad genre. It's kind of like how
         | "bronchitis" actually just means "enflamed bronchial tubes" -
         | it's a symptom, not a cause. Even if we permanently defeat SYN
         | floods, there are a gazillion other DDoS-type attacks (UDP
         | flooding, messing with ARP tables - its an almost endless
         | list).
        
           | stingraycharles wrote:
           | > Note that DDoS attacks are a class of attacks. They're a
           | description for a broad genre.
           | 
           | While they may be a class of attacks, I would describe all of
           | them as undesired requests. Sometimes, with some clever
           | protocol design, you can, in fact, mitigate a whole class of
           | problems.
        
           | nickthemagicman wrote:
           | Seems like that's another benefit of IPv6.
           | 
           | Without needing NAT everyone can have their own IP address
           | and biz will be able to ban individual machines instead of
           | some giant NAT Network because one host using that IP address
           | is compromised.
        
             | laurensr wrote:
             | Doesn't it also mean addresses serving as the source of an
             | attack become more disposable?
        
             | bluedino wrote:
             | A trillion hosts.deny entries?
        
             | MrStonedOne wrote:
             | if you are sending packets but don't care about the reply,
             | you can spoof the from header.
             | 
             | The other form of ddos is udp amplification. you send a
             | packet to a legit host and spoof the target ip as the from
             | ip, the reply goes to your target and bam, ddos.
        
               | kazen44 wrote:
               | this could be solved in ipv6 by implementing ipsec in AH
               | mode.
        
           | ma2rten wrote:
           | Yes, but these attacks are actually easy to detect if they
           | all come from the same IP. Sending packages from a lot of
           | different IPs actually is expensive.
        
             | alasdair_ wrote:
             | The attacks come from (up to) millions of different ip
             | addresses, each one a different machine and often on a
             | residential network.
             | 
             | This is the problem with botnets - all the connections look
             | like real traffic at first glance.
        
             | menmob wrote:
             | That's.. not what a _Distributed_ Denial of Service does.
             | They come from thousands of IPs.
        
             | bravetraveler wrote:
             | That's the first 'D' in DDoS - _distributed_.
             | 
             | Most robots participating in this are unwitting. It's
             | incredibly unlikely someone is _paying_... even with stolen
             | funds.
             | 
             | Often a sort of malware that more or less sits dormant
             | until command/control sends a target to attack
             | 
             | edit: To the individual machine, not a lot. The sum total
             | is where the denial of service comes in - everything has a
             | tipping point.
        
             | oneplane wrote:
             | It's not expensive if you have a botnet, reflective attacks
             | or L7 attacks. It's also not just one type of attack
             | (overloading the target), the only thing in common is that
             | it's a denial of service, and if you distribute it amongst
             | many sources it's a distributed denial of service.
             | 
             | Distributed can mean different things, especially if you
             | can spoof addresses, in which case you can do fake
             | distribution (causing src based filtering to be useless).
             | If you know it's just a single bad AS that is doing it,
             | then you can block the AS, but if it's distributed amongst
             | multiple AS'es that's harder. Same with reflective attacks,
             | the source of the traffic might not be the source of the
             | attack and might be a legitimate source which you cannot
             | block because your internet wouldn't work anymore (i.e.
             | when it's DNS servers or NTP servers doing the reflection,
             | or a GCN address which would completely take an ISP's
             | section offline).
             | 
             | It's not as simple as sending a large volumetric load from
             | A to B. It used to be that way a decade ago and it can be
             | effective today, but it's not the only way it's happening.
        
             | MrStonedOne wrote:
             | The src ip can be spoofed and randomized if you don't care
             | about getting the response (and to some degree, you care
             | more about _not_ getting it)
        
           | vladf wrote:
           | Why is this resource asymmetry unavoidable? It seems
           | reasonable that a new protocol could solve it.
           | 
           | Consider augmenting TCP with a "pre-SYN" and "pre-SYNACK".
           | Suppose you have to send a pre-SYN which declares your
           | identity ip X. Then the server sends to X a "pre-SYNACK"
           | encrypted message containing (X, t = timestamp()) based on a
           | server-only key.
           | 
           | Afterwards, X may send the server a SYN for real. But then
           | the server only allows a timeout of length, say, timestamp()
           | - t, as of receiving the SYN back to maintain bookkeeping.
           | 
           | As benevolent cooperating clients, we may want to _ourselves_
           | wait an exponentially-backed-off amount between receiving the
           | pre-SYNACK from the server and sending our SYN back (such
           | that in log-many rounds we establish our conn).
           | 
           | Then any malevolent actor must then keep a resource on X
           | alive for at least half long as the server does (since the
           | server requires zero bookkeeping after firing off the pre-
           | SYNACK).
           | 
           | Edit: this is simplified, you could just own a machine at X
           | which is far away from the ddos'd server and then have your
           | botnet spoof requests from X; by augmenting this procedure
           | with even more preamble rounds you could verify how long
           | communication takes between the server and client X and
           | subtract that out.
        
             | tw04 wrote:
             | You're too lazer focused on syn attacks, there are
             | countless others. What it boils down to is the sheer size
             | of the botnets. You stop syn? Great, I'll make it UDP with
             | a max payload and send it from 500k hosts. You will
             | eventually fall over if my botnet is big enough.
        
             | ajsnigrutin wrote:
             | > Why is this resource asymmetry unavoidable? It seems
             | reasonable that a new protocol could solve it.
             | 
             | Sending a HTTP GET is easy, but the server has to process
             | the request and send the whole page... think a few tens of
             | bytes of a request, and a whole webpage in a reply.
        
             | brians wrote:
             | The server has to do an encryption and a decryption. A
             | legit client has to do the pre-SYN dance. In your protocol,
             | I don't spam pre-SYNs; I spam SYNs with fake tokens. Thus I
             | send only the same number of packets as before, but the
             | server has to do these decryptions! Or I can mix and match
             | spoofed SYNs with pre-SYNs and legitimate SYNs in whatever
             | way finds the best leverage.
             | 
             | Your pre-SYN design is very close to the design of TLS 1.2,
             | by the way. That's how I knew how to attack it. TLS is
             | attackable in just this way: open a real connection, then
             | lots of fake handshake requests. No crypto required to
             | generate them, but the server has to do lots.
             | 
             | Now that said, BCP 38 would go a LONG way towards
             | addressing this. There will come a day when the well-
             | behaved networks decide they're not accepting traffic from
             | non-compliant peers.
        
               | kazen44 wrote:
               | mind you BCP38 will do nothing against legitimate IP's
               | used in DDoS attacks. (which are more and more common
               | because of large botnets thanks to IoT devices and their
               | abysmal security).
        
             | catmanjan wrote:
             | So a bit like a proof of work concept for packets? Doesnt
             | sound like such a crazy idea to me
        
             | Matthias247 wrote:
             | > Why is this resource asymmetry unavoidable? It seems
             | reasonable that a new protocol could solve it.
             | 
             | Protocols are trying to avoid this problem. For TCP there
             | exist SYN cookies to reduce the amount of work a host has
             | to do. For QUIC retry packets exist, as well as anti-
             | amplification rules. However applying those mechanisms also
             | has a cost. One is you still get computational cost not to
             | zero, since you still have to receive and reject packets.
             | And the other cost is now your legitimate users are
             | experiencing a latency penality due to potentially
             | requiring another round trip.
             | 
             | The latter means you don't want to make those mechanisms
             | the default, but rather use them selectively in certain
             | situations.
             | 
             | The former means even if you apply countermeasures you are
             | not fully protected. If you get flooded purely by the bare
             | amount of packets and the system stalls just from handling
             | them, all the higher level mitigations won't work very well
             | anymore. That's the difference between a DDoS and a DoS -
             | the DDoS might not even need an asymetry in cost, it just
             | brute-forces the system down.
        
             | jcrawfordor wrote:
             | This method is basically already in use for DOS mitigation
             | using a technique called a SYN cookie. But as the parent
             | said, there is a huge spectrum of different ways to produce
             | a DOS and so there is no single method of addressing them.
             | The problem tends to be much harder as you get to higher
             | levels, for example, requesting things from an HTTP server
             | - there are mitigations available there as well such as
             | Cloudflare's approach of capturing DoS like requests and
             | subjecting them to CAPTCHA, but once again no one size fits
             | all.
        
               | vladf wrote:
               | I guess the problem is "simply" the use of these
               | resource-asymmetric protocols. As a server-owner, if
               | there was a robust alternative protocol which ensured
               | resource symmetry, wouldn't you be naturally incentivized
               | to adopt it and reject all asymmetric ones?
               | 
               | It still _feels_ like there 's a way of specifying a
               | protocol (which of course would need to be adopted) where
               | (1) authentication is a first-class entity (2) all non-
               | authenticated requests enforce resource symmetry at the
               | protocol level, while still allowing asymmetric work to
               | be done (after a resource-symmetric auth).
               | 
               | Edit: augmenting the rough outline of what I originally
               | proposed you can essentially require an arbitrary amount
               | of proof-of-work, however useless, on the requester side
               | (e.g., literally request a nonce such that the hash of
               | the packet is below some value). Since only auth needs to
               | be symmetric the overhead doesn't seem too bad.
        
               | Bootvis wrote:
               | If we do some form of authentication it seems likely that
               | the receiving side needs to do some kind of computation.
               | What if I just sent garbage? Garbage is easy to create
               | but the receiver needs to do some work to figure this
               | out.
        
               | vladf wrote:
               | Hrm, I don't think you're engaging with the spirit of my
               | proposal, which _does_ require resource-symmetry to
               | establish auth in the protocol.
               | 
               | I admit I haven't specified a full counterfactual
               | protocol here, but see my edit for a rough outline of how
               | you wouldn't just be able to generate garbage.
        
               | psd1 wrote:
               | You said "I feel that..." so I suppose you're an mbti 'F'
               | - excellent choice! But I feel you'll work on this idea
               | for a bit and then throw your hands up.
               | 
               | The symmetry is irrelevant when the attacker has stolen
               | someone else's resources. Granny may notice her computer
               | is even slower than usual, what then?
               | 
               | If we stipulate a future where attackers cannot steal
               | other people's resources, then work backwards, I can't
               | see any internet with any degree of freedom.
               | 
               | It would be necessary for every system to be 100%
               | watertight. Mathematically-provably so. Spectre/Meltdown
               | demonstrates that this isn't just formal proof about
               | software. Eradicating the pathways to ddos is an
               | intractable problem. You'd need to seriously consider
               | preventing all network access except through certified
               | and regulated kiosks to which users do not have direct
               | physical access. Like, hand a librarian a piece of paper
               | with a URL on it and get a print out.
               | 
               | I'm not expert, you shouldn't have confidence that I'm
               | correct.
        
               | spenczar5 wrote:
               | Yes, I think there is a lot of room for better protocols
               | that reduce the asymmetry. A lot of our internet is built
               | on protocols that assumed good behavior, since back in
               | the 70s and 80s and even 90s that was plausible.
               | 
               | But I don't think we will ever get to a point where we
               | bring that asymmetry to zero. We often really do want
               | complex tasks to be done by a server in response to a
               | simple client request.
               | 
               | Software people rarely put this asymmetry in the front of
               | their minds during design, so I think its something we
               | will continue to see in new systems, even if we
               | (magically) universally adopted better versions of the
               | old, too-trusting protocols.
        
               | imranhou wrote:
               | Not to mention, implementation of new protocols is one
               | thing, adoption of such protocols is another - I would
               | dare say the harder part of the two. If you are required
               | to serve a population that won't keep up, its an uphill
               | battle.
        
             | hansvm wrote:
             | > Why is this resource asymmetry unavoidable? It seems
             | reasonable that a new protocol could solve it.
             | 
             | There's some sense in which a little asymmetry is
             | unavoidable -- a malicious attacker can always just send
             | whatever bytes they want over the wire, and a server on the
             | other end with any practical purpose must at a minimum
             | receive each of those bytes AND perform some operation
             | equivalent to determining if any more work needs to be
             | done.
             | 
             | To the extent that any real work or state management needs
             | to be done by the server, the only way to avoid much
             | asymmetry is to use a protocol forcing the client calls to
             | be artificially more expensive before the server will agree
             | to respond.
        
               | psd1 wrote:
               | Yes and... a botnet controller simply doesn't care
               | anyway. She or he isn't spending their own resources.
        
             | robocat wrote:
             | The server would still need to track some state.
             | 
             | Worse, the cost is another round trip delay. That's a
             | problem for anyone with a high latency connection.
        
               | vladf wrote:
               | Right, under the previously unspecified constraint that
               | you need a response in one round trip I agree there's a
               | natural resource asymmetry.
        
             | toast0 wrote:
             | The fundamental asymmetry is bandwidth. If you can
             | overwhelm my incoming connection, I can't do much useful
             | work.
             | 
             | I've got to pay for capacity, but a bot net controller
             | doesn't need a whole lot of bandwidth to trigger a lot. If
             | you control 10,000 hosts with 10Mbps upload, that's
             | 100Gbps; and botnets are growing as are typical upload
             | bandwidths.
             | 
             | And that's without spoofing and amplified reflection
             | attacks. Some of the reflection attacks have high
             | amplification, so if you've got access to 100Gbps of
             | spoofable traffic, you can direct Tbps of traffic.
             | 
             | If my server has a 10G connection and you're sending me
             | 1Tbps, there's just no way I can work.
             | 
             | Syncookies work pretty well for TCP, I had run into some
             | effective SYN floods against my hosts I managed in 2017,
             | but upgrading to FreeBSD 11 got me to handling line rate
             | SYNs on a 2x 1Gbps box and I didn't take the time to test
             | 2x10G as I wasn't really seeing that many SYN floods. I
             | don't recall any more effective SYN floods after that
             | point. We didn't tend to have dedicated attackers though;
             | people seemed to be testing DDoS as a service against us,
             | and we'd tend to see exactly 90 or 300 seconds of abuse at
             | random intervals.
             | 
             | Our hosting provider would null route IPs that were
             | attacked if the volume was high enough for long enough.
             | Null routing is kind of the best you can hope for your
             | upstreams to do, but it's also a denial of service, so
             | there you go.
        
         | lend000 wrote:
         | With DDoS the problem is that botnets come from a bunch of
         | random devices that were compromised (for example, your un-
         | updated smart TV or old router could be contributing to the
         | DDoS without your knowledge.)
         | 
         | With spam calls, ransomware, and most other forms of
         | cybercrime, the problem is that Russia/China and many 3rd world
         | countries don't extradite/cooperate or have the resources to
         | work with international authorities.
         | 
         | I sometimes wonder how much safer the internet would be if
         | China and Russia were cut off. Wouldn't be so great for the
         | already poor state of liberty in either country, but the rest
         | of the world would certainly benefit.
        
           | ChuckNorris89 wrote:
           | _> Wouldn't be so great for the already poor state of liberty
           | in either country, but the rest of the world would certainly
           | benefit._
           | 
           | That's a pretty closed minded way of looking at things.
        
           | [deleted]
        
           | Andrew_nenakhov wrote:
           | Cutting off countries will do very little. Compromised
           | devices are spread evenly across the globe, and even if their
           | puppeteers sit in China or Russia, you wouldn't be able to
           | block them from issuing orders to botnets.
        
           | spenczar5 wrote:
           | It's true that they often use botnets, but amplification
           | attacks are more and more common, and an important component
           | here.
           | 
           | In these, the attacker sends crafted requests to an unwitting
           | third party, and that third party then floods the victim with
           | traffic. DNS amplification is probably the best known, here,
           | since DNS is (usually) over UDP which has no persistent
           | connection for replies:
           | 
           | - Send a DNS query to a DNS server, using your victim's IP
           | address as the "source IP" for the query. Make the query
           | something with a huge response, like using "ANY".
           | 
           | - DNS server responds to the victim's IP address, sending
           | many big UDP packets with the response. After all, it can't
           | know any better - it must* just trust the claimed source IP!
           | 
           | - Victim gets a huge flood of UDP traffic, overwhelming IP-
           | level infrastructure like routers and switches.
           | 
           | This lets a relatively small attacker multiply ("amplify")
           | their impact - and they do it while traversing a third party,
           | making them more hidden.
           | 
           | ---
           | 
           | * If course, there actually are mitigations for this; it's
           | possible to detect this spoofing. But this is how DNS
           | operators have worked in the past.
        
           | NicoJuicy wrote:
           | That's the reason why my nextdns blocks all _.ru and_.ch
           | domains.
           | 
           | I don't trust them + i don't speak the language. So entirely
           | blocking it is an easy decision.
           | 
           | Nextdns on my router blocks generated domains, which could be
           | used against c&c servers.
        
             | forty wrote:
             | .ch is Swiss TLD ;)
        
           | edflsafoiewq wrote:
           | > the rest of the world would certainly benefit
           | 
           | OTOH most pirate library sites are hosted in those countries
           | for the same reason.
        
           | jansimonek wrote:
           | "without your knowledge"... is there a way to check if my IP
           | was participating in the DDoS? If they are filtering the
           | traffic, they might be able to create a list of IPs that I
           | can check. Or perhaps, an IP can be associated with a contact
           | info so the if any of my devices would be infected and
           | participate in DDoS, I would get notified by the victim and
           | could take action.
        
         | jl6 wrote:
         | Imagine the real-world equivalent: someone spreads a rumor that
         | the Fifth Avenue Apple store is giving away free iPhones at
         | 6pm. Ten thousand people turn up and block the store, the
         | sidewalk, the roads...
         | 
         | How should a business defend against that without losing
         | legitimate customers?
         | 
         | The answer is probably along the lines of "educate people not
         | to believe rumors" (:: "educate people not to run insecure
         | software").
        
           | smoldesu wrote:
           | How does secure software protect you from acknowledging
           | perfectly innocuous requests?
        
             | jl6 wrote:
             | It's the zombie-botnet-machine owners who need to be
             | running more secure software, not the botnet victims.
        
         | jjeaff wrote:
         | Most/all ddos attacks come from unwitting people whose
         | computers or iot devices have been taken over on the order of
         | tens or hundreds of thousands of devices. So there isn't much
         | that can be done beyond filtering or having a large enough
         | pipeline to absorb the traffic.
         | 
         | Even if you had a central authority cutting off access from ip
         | addresses, do you cut off whole university campuses because
         | someone's "smart" coffee machine is participating in a ddos or
         | entire businesses because there is a computer in a closet
         | somewhere that is infected?
        
           | mrweasel wrote:
           | We talked about this problem when I worked at a telco. The
           | problem isn't necessarily cutting of the devices that are
           | part of the attack, it's dealing with the aftermatch.
           | 
           | As sad as it is, most people won't understand that their
           | device have been effected, and the telcos won't be
           | responsible, financially, for paying to do the cleanup or
           | verification.
        
           | toxik wrote:
           | I feel like home router makers could intervene here and let
           | their owners know when they've likely been hacked. Maybe even
           | a regulation type deal?
        
             | logifail wrote:
             | > home router makers could intervene here and let their
             | owners know when they've likely been hacked
             | 
             | How?
             | 
             | A couple of years ago I had an email from our ISP telling
             | me that "common port X is open on your router" (forwarded
             | to a box exactly as I set it up) and asking if I could "fix
             | the problem".
             | 
             | Except it wasn't a mistake or a configuration error, I
             | deliberately set it up that way.
        
             | foxfluff wrote:
             | I don't see how this would be feasible without giving them
             | a backdoor to snoop around in my home network. No thanks.
        
             | MertsA wrote:
             | That's never going to work but it very well could lead to
             | ISPs very strongly herding customers to use their own
             | managed routers. They already push for that for customer
             | support purposes, using this to start automatically
             | snooping on "malicious" traffic within a customer's network
             | would be a big step in the wrong direction.
             | 
             | You could make a compromise here and require ISPs and
             | network vendors to support a common notification protocol
             | to identify devices sourcing malicious traffic. Most ISPs
             | already have systems in place to send notification messages
             | to customers that are sending botnet traffic. You could
             | mandate it for all of them and let the customer decide if
             | they want their router configured to automatically block a
             | device they were notified about or just record the MAC
             | address and send the ISP a URL the user can visit to view
             | the device sending the traffic. You could make it friendly
             | to the unwashed masses and still put detection on the ISPs
             | and not give them privileged access inside every customer's
             | network.
        
         | Arnt wrote:
         | It's not that simple. Collecting 250Gbps of uplink is not that
         | simple. The attack vectors are simple in principle, but
         | carrying it out...
         | 
         | Here's next year's fine vector: You write a nice iphone or
         | android app and persuade fifty million people to download it.
         | But unknown to the owners of those mobile phones, it also has a
         | hidden evil feature: If the phone has the screen off, is
         | charging and is on a WLAN, then it can participate in a DDoS if
         | you direct them to. The phone's owner won't notice, but if
         | enough phones are charging and each can contribute 2Mbps of
         | upload, you could collect 250Gbps at the target.
         | 
         | And tracing it back to that app will be very difficult.
        
           | jonplackett wrote:
           | Why would it be so hard to trace back?
        
             | [deleted]
        
             | johnklos wrote:
             | It wouldn't be hard.
             | 
             | If you can examine traffic on a network from which
             | attacking traffic originates, you can see that it's coming
             | from a phone.
             | 
             | Then you could see which app by either limiting or deleting
             | apps one at a time, or you'd need two sources, then just
             | see which apps the two sources have in common.
             | 
             | When you have 250 Gbps, it'd be simple to capture a
             | fraction of a second's worth of traffic, then write a
             | script to fire off emails to network admins of every IP
             | involved and ask them to look in to it. Out of hundreds or
             | thousands of messages, you'll get a few humans who'd look
             | in to it and would be helpful.
             | 
             | I should know, because I've done this very thing.
        
             | Arnt wrote:
             | If your nontechnical neighbour's ISP calls and says "you're
             | participating in a DDoS, will you please find out which
             | device behind your NAT is sending the traffic and fix
             | whatever the problem is", do you think your neighbour can
             | fix it in five minutes?
        
               | edoceo wrote:
               | They could remote stop the router?
        
               | tinus_hn wrote:
               | A responsible ISP will block the user but this means the
               | user is going to call the helpdesk which costs money.
               | 
               | An irresponsible ISP will stall the process to see if you
               | give up, which is free.
        
             | MrStonedOne wrote:
             | because nothing says you have to include your real ip in
             | the src header of the ip packet if you don't care about the
             | reply.
        
           | lordnacho wrote:
           | What's the solution to this? If millions of devices are each
           | sending 2Mbps to some target, what can the target do? It
           | doesn't sound like there's a program that would be able to
           | identify something so diffuse.
        
             | kazen44 wrote:
             | remote triggered blackholing the networks from which the
             | ddos comes is very effective for small DDoS's. but its a
             | very crude methods that drops entire /24's from being able
             | to reach you.
             | 
             | this doesn't work for massive ddos's.
        
             | Arnt wrote:
             | I think you understand why edpnet.be has problems now.
             | 
             | What they usually do is try to write packet filter rules
             | and drop packets as close to the millions of origins as
             | possible, plus call the networks where the sending devices
             | are and say things like "could you please call your
             | customers and tell them to unfuck their {phones,dsl
             | routers,...}"
        
             | speakersPushAir wrote:
             | It is intrinsic to the design.
             | 
             | The open nature of the protocol carries with it an implicit
             | trust. Any client may join and speak to any other client
             | and be heard. It is a social contract, just as we have "in
             | real life."
             | 
             | Imagine someone knocks on your door. You can choose to not
             | answer, but even considering the choice costs you cognitive
             | bandwidth. As long as you're within earshot of your door, a
             | knock will cost you attention.
             | 
             | We have solutions all across the spectrum, from putting up
             | a "no soliciting" sign, to arresting bad actors. But what
             | if you have a riot outside your front door (a DDoS)?
        
           | tinus_hn wrote:
           | On iOS the OS does not allow apps to do this, you basically
           | can only use the OS APIs to do networking in the background
           | so clever tricks are right out, and it is throttled.
        
           | sydd wrote:
           | Google/Apple will catch you in hours/days and all your work
           | goes down the drain. Also its hard to get 50M downloads, not
           | worth the time.
           | 
           | There is already an established economy of botnets. They work
           | like this:
           | 
           | 1. There is a hacker group (usually ex-USSR or China) that is
           | actively monitoring 0 day vulnerabilities. They usually
           | target internet connected devices which are from companies
           | that dont give a damn about updating them after they are
           | released. This is the case for most budget routers, "smart"
           | things (lamp, frigde, vacuum, doorbell,..).
           | 
           | 2. If they find a nice one (e.g. one that affects millions of
           | shit-tier $40 routers), they set up port scanners and infect
           | as many as they can.
           | 
           | 3. Rent the botnet on darknet sites, there is already an
           | established pricing for them, for example $1000 for 1 hour of
           | 1000Gbps DDOS. You just pay them in crypto and tell what to
           | attack.
        
             | cookiengineer wrote:
             | > Google/Apple will catch you in hours/days
             | 
             | Tell that to the Hola and Honey extensions. They're known
             | to be a botnet and for this kind of abuse for years yet you
             | can still find them everywhere in the App/Play Store...and
             | _so_ many tech related youtube channels keep advertising
             | for them blindly, it's ridiculous.
        
               | c0nducktr wrote:
               | I had heard that Hola was possibly some kind of malware,
               | but this is the first I'm hearing that Honey (I'm
               | assuming we're both talking about the coupon-code
               | extension) is like that too.
               | 
               | I just figured Honey was kind of like spyware, collecting
               | information about what people bought online.
        
           | deadalus wrote:
           | (2015) Imgur was being used to create a botnet and DDOS 8Chan
           | : https://news.ycombinator.com/item?id=10256942
        
           | ma2rten wrote:
           | It's not that easy to get 50 million people to download your
           | app and if you pulled that off there are more profitable
           | things you could do.
        
             | nine_k wrote:
             | Why limit it to DDoSing? It could be just one feature, but
             | an important one.
        
             | leroman wrote:
             | Toolbars did just that and been used for many "evil"
             | things..
        
             | Arnt wrote:
             | My point exactly.
             | 
             | These things are easy to do in principle (most readers here
             | can write that evil payload, or learn how to do it quickly)
             | but there are real practical challenges to getting the code
             | to run on millions of strangers' computers/phones/dsl
             | routers, so most of the code that's actually deployed that
             | widely is beneficial. Happily.
        
           | mvanbaak wrote:
           | Unpopular opinion and will get downvoted:
           | 
           | This is why the appstores do reviews etc. these kind of
           | things dont happen because of that
        
             | Groxx wrote:
             | ... except that they most definitely do still happen in
             | spite of that.
             | 
             | But yes, they do tend to mean less obviously-just-malware
             | apps.
        
         | ancarda wrote:
         | As far as I know, a lot of DDoS attacks use UDP amplification,
         | which can be prevented if every ISP implements BCP 38; i.e.
         | drop UDP traffic at the edge of their network that has a source
         | that cannot have come from within their network.
         | 
         | EDIT: To clarify, this won't stop layer-7 based DDoS attacks,
         | or anything that uses TCP (like SYN flooding). Just UDP
         | amplification.
        
           | woutifier wrote:
           | BCP 38 would stop SYN flooding if it is using source address
           | spoofing. It won't stop any attack not based on IP spoofing
           | though.
        
           | MertsA wrote:
           | >or anything that uses TCP (like SYN flooding)
           | 
           | Plenty of SYN floods spoof IP as well. If you don't need to
           | get the response, and you're behind an ISP that doesn't
           | bother blocking IP spoofing, why would you use your actual
           | IP? It'll make it much harder to actually trace an attack to
           | the actual device doing it. It won't work on devices behind
           | NAT but neither will reflected UDP attacks.
        
         | hirako2000 wrote:
         | The issue is: bot nets. The attacks come from multiple sources
         | worldwide. No anonymity, rather a swarm of legitimate hosts
         | sending mass;requests. Research and development? Network
         | connections come in, one way or another some devices have to
         | filter them in or out. AFAIK it's an arm race. Large bot nets
         | on one side, and hardware optimised to filter out certain
         | requests on the other.
         | 
         | It's a simple technique but requires compromising enough
         | networked resources to make the attack effective.
         | 
         | Cloudflare and other providers having large capacities are well
         | armed to deflect DDoS that can't overwhelmed them, but even
         | then, they aren't safe from a larger bot net than what their
         | network resource can handle.
         | 
         | If someone knows more than I do, maybe they could elaborate on
         | technologies I'm not aware of.
        
         | johnklos wrote:
         | Simple - egress filtering:
         | 
         | https://en.wikipedia.org/wiki/Egress_filtering
         | 
         | If every large network operator did this, then shutting down
         | abusive hosts used to generate the kind of traffic needed for
         | attacks like these would be possible.
         | 
         | You'd make a list of all the IPs for each large provider from
         | which excess traffic is coming, and you'd send them to each
         | large provider, and they'd either block the IPs completely
         | (requiring customers to fix their compromised machines before
         | they could get back on the Internet), or at very least they
         | would block all traffic to the destination of the attack.
         | 
         | Some silly people think this isn't possible, but if large
         | providers are forced to do it, then they can easily tell
         | smaller ones they'll be blocked if they don't also do this, and
         | so on, and we'd have a slightly more responsible Internet
         | again.
         | 
         | Too bad we have shitty, huge companies that don't care about
         | doing the right thing :(
        
           | toast0 wrote:
           | > Some silly people think this isn't possible, but if large
           | providers are forced to do it, then they can easily tell
           | smaller ones they'll be blocked if they don't also do this,
           | and so on, and we'd have a slightly more responsible Internet
           | again.
           | 
           | You go ahead and force a large provider to do it, and let us
           | know how. From what I can tell from reading NANOG mailing
           | list posts off and on for decades is that most of the larger
           | providers really won't be bothered to do this, and there's
           | not any effective leverage to force them.
        
           | Hikikomori wrote:
           | No, the solution is ingress filtering and a lot of ISPs do it
           | these days, see bcp38.
        
           | [deleted]
        
           | yjftsjthsd-h wrote:
           | > Some silly people think this isn't possible, but if large
           | providers are forced to do it, then they can easily tell
           | smaller ones they'll be blocked if they don't also do this,
           | and so on, and we'd have a slightly more responsible Internet
           | again.
           | 
           | > Too bad we have shitty, huge companies that don't care
           | about doing the right thing :(
           | 
           | There's no call to be dismissive of anyone who disagrees with
           | you; maybe you're "silly" for believing that companies will
           | threaten each other for no reason (that they care about).
        
             | Jweb_Guru wrote:
             | Nope, they are basically right and it's a source of endless
             | frustration to security researchers that these very simple
             | problems are still thinks that have to be dealt with in
             | 2021.
        
         | phkahler wrote:
         | >> Since this is HN, it's 2021 and DDoS'es are still a thing:
         | why are they still a thing? Is there some fundamental
         | "anonymity" to the Internet that makes it impossible to
         | structurally prevent DDoS attacks?
         | 
         | IMHO that is exactly what the problem is. Weather its malware,
         | phishing scams, extortion schemes, the fundamental problem is
         | _knowing_ where stuff comes from.
         | 
         | I propose an IPv6 subnet that routes by using a portion of the
         | IP address as lat/long coordinates _as a starting point_
         | because routing tables are litterally a form of indirection.
        
           | yjftsjthsd-h wrote:
           | > an IPv6 subnet that routes by using a portion of the IP
           | address as lat/long coordinates
           | 
           | That seems like a rather large privacy problem.
        
         | matheusmoreira wrote:
         | You could for example protect all networked computers with
         | single packet authorization. They will ignore all network
         | traffic unless a signed packet is sent first. To the
         | unauthorized it's like the computer is not even there.
        
           | kazen44 wrote:
           | this is basically how a vpn tunnel works in some way.
           | (wireguard, ipsec if properly configured etc).
           | 
           | it has one, enourmous downside. it destroys reachability to
           | your systems from the population at large because they need
           | to trust some key, which is not universally distributed.
        
         | LinuxBender wrote:
         | There are many parts to the answer of your question, but one
         | part yet to be implemented in a meaningful manor is BCP38 [1].
         | The RFC's around BCP38 keep changing and that may be part of
         | the issue. It is still too easy to spoof the source across ISP
         | boundaries. Then of course there is also the issue of getting
         | all the ISP's to work together to detect and mitigate these
         | attacks and that involves cost that the tier 1 providers barely
         | spend towards. There are so many more pieces to this problem
         | and I am barely touching on it.
         | 
         | [1] - https://www.rfc-editor.org/info/rfc8704
        
         | gxt wrote:
         | There are very little consequences.
         | 
         | Until states start doing s/sea/internet/g on their old-school
         | maritime piracy laws[0] I don't think anything is going to
         | change, except attacks are gonna get bigger and bigger.
         | 
         | Under current law, that's a lifetime sentence in many*(US[1] &
         | Canada[2] at least) countries. It should do the trick if most
         | states get onboard.
         | 
         | > Acts of piracy threaten internet security by endangering, in
         | particular, the welfare of internetfarers and the security of
         | navigation and commerce. These criminal acts may result in the
         | loss of life, physical harm or hostage-taking of
         | internetfarers, significant disruptions to commerce and
         | navigation, financial losses to server owners, increased
         | insurance premiums and security costs, increased costs to
         | consumers and producers, and damage to the internet
         | environment. Pirate attacks can have widespread ramifications,
         | including preventing humanitarian assistance and increasing the
         | costs of future connectivity to the affected areas.
         | 
         | [0] https://www.un.org/depts/los/piracy/piracy.htm [1]
         | https://www.law.cornell.edu/uscode/text/18/1651 [2]
         | https://laws-lois.justice.gc.ca/eng/acts/c-46/page-11.html#s...
        
       | mfkp wrote:
       | I wonder if this is related to the attack on voip.ms (ongoing for
       | multiple days)
       | 
       | https://twitter.com/voipms
        
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