3 ms·

Large bandwidth attacks might look sexy, but they're trivially easy to block. Network operators care about pushing packets, not bits. The OVH attacks look huge

by scurvy 10y ago

Large bandwidth attacks might look sexy, but they're trivially easy to block. Network operators care about pushing packets, not bits. The OVH attacks look huge to the average AWS user, (ZOMG a terabit!) but to even an average tier 2 transit provider it's a trivial attack to block. Especially when the attackers are hitting a single endpoint. To be honest, attackers are not very smart. They almost always use the same old attacks, attacks that are easily stoppable, and attacks against a single IP. 100gig coherent is easily turning volumetric attacks into old hat. Ending spoofed attacks today is a tactic that's 10 years too late.

hueving 10y ago
It's not trivial by any means other than preventing it from clogging up internal stuff. If they are targeting a specific IP and the traffic is indistinguishable from normal traffic in the l3/l4 headers, there is no way you are going to block the attack without taking down the service. This is why solving spoofing is such an important problem. Once source IPs become sticky, we can actually block based on them to truly stop the attack without taking down the service.
- scurvy 10y ago
  You block volumetric attacks by filtering the payload, not by blocking IP's. If you block by IP, you're going to have a lot of upset customers. Also, what are you going to do on an IPv6 attack? Block the entire /64? Unlikely. Also remember that a single IP doesn't always mean a single user for IPv4. An IP might represent several thousand customers in the case of NAT and especially CGNAT. If the traffic is indistinguishable from normal traffic via L3/L4, then it's a layer 7 attack, which cannot be spoofed. You're not dealing with spoofing in a L7 attack. The first D in DDoS stands for distributed. Even terabit sized attacks are easy to stop if they're sufficiently distributed (the attack is geographically dispersed enough to be diffused). It's when you get a terabit from a handful of AS's (like in S. Korean attacks) that you can feel pain. Even then, it usually only knocks out access in that part of the world, but not everyone. IP's will not be sticky. IPv6 is showing why it's important to not be sticky. Ending spoofing isn't going to stop DDoS attacks. I've got 10+ years of experience on the subject, and I'll gladly answer any questions you might have.
  - hueving 10y ago
    Yes, you block by IP and piss off customers or the whole /64 if necessary. IPs will almost always be sticky to the advertised prefix. A TCP SYN, or any UDP initial request indistinguishable from legit traffic of the same protocol at L3/L4, and both can be spoofed so I don't know where you got the idea that they cant be spoofed and are L7 only. If you're "stopping the attack" through dispersion, you're not actually stopping it, you're just paying the price of absorbing it. I know this is common practice, but it's pathetic than an arms race is the state of the art in defense. It concentrates power into orgs like cloudflare, akamai, and Google (project shield) because the only way to participate is to use them.

by scurvy 10y ago

hueving 10y ago

It's not trivial by any means other than preventing it from clogging up internal stuff. If they are targeting a specific IP and the traffic is indistinguishable from normal traffic in the l3/l4 headers, there is no way you are going to block the attack without taking down the service. This is why solving spoofing is such an important problem. Once source IPs become sticky, we can actually block based on them to truly stop the attack without taking down the service.

scurvy 10y ago
You block volumetric attacks by filtering the payload, not by blocking IP's. If you block by IP, you're going to have a lot of upset customers. Also, what are you going to do on an IPv6 attack? Block the entire /64? Unlikely. Also remember that a single IP doesn't always mean a single user for IPv4. An IP might represent several thousand customers in the case of NAT and especially CGNAT. If the traffic is indistinguishable from normal traffic via L3/L4, then it's a layer 7 attack, which cannot be spoofed. You're not dealing with spoofing in a L7 attack. The first D in DDoS stands for distributed. Even terabit sized attacks are easy to stop if they're sufficiently distributed (the attack is geographically dispersed enough to be diffused). It's when you get a terabit from a handful of AS's (like in S. Korean attacks) that you can feel pain. Even then, it usually only knocks out access in that part of the world, but not everyone. IP's will not be sticky. IPv6 is showing why it's important to not be sticky. Ending spoofing isn't going to stop DDoS attacks. I've got 10+ years of experience on the subject, and I'll gladly answer any questions you might have.
- hueving 10y ago
  Yes, you block by IP and piss off customers or the whole /64 if necessary. IPs will almost always be sticky to the advertised prefix. A TCP SYN, or any UDP initial request indistinguishable from legit traffic of the same protocol at L3/L4, and both can be spoofed so I don't know where you got the idea that they cant be spoofed and are L7 only. If you're "stopping the attack" through dispersion, you're not actually stopping it, you're just paying the price of absorbing it. I know this is common practice, but it's pathetic than an arms race is the state of the art in defense. It concentrates power into orgs like cloudflare, akamai, and Google (project shield) because the only way to participate is to use them.