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The real reason for large DDoS attacks? It's IP Spoofing, not memcached

blog.cloudflare.com

1–10 of 38 posts

Re: The real reason for large DDoS attacks? It's IP Spoofing, not memcached

#2
>Let's take a deep breath and discuss why such large DDoS attacks are even possible on the modern internet.

Because all traffic is treated at face value and not deep filtered and throttled according to some company's whims.

Cloudflare wants to change this. Cloudflare wants centralization. Cloudflare wants blacklists.

Re: The real reason for large DDoS attacks? It's IP Spoofing, not memcached

#3
post #2

>Let's take a deep breath and discuss why such large DDoS attacks are even possible on the modern internet. Because all traffic is treated at face value and not deep filtered and throttled according to some company's whims. Cloudflare wants to change this. Cloudflare wants centralization. Cloudflare wants blacklists.

They are not suggesting centralization. They are suggesting bcp38 [0] This comes up quite often and people argue back and forth why they (the ISP's) can't or won't do this. Bcp38 simply requires ISP's to egress filter out IP traffic that does not belong to them.

[0] - https://tools.ietf.org/html/bcp38

Re: The real reason for large DDoS attacks? It's IP Spoofing, not memcached

#4
Are there any valid technical use-cases for IP spoofing? i.e. setting the source address of a UDP packet as one outside the originating network?

For example, on the server side, BGP hijacking and anycast routing are enabled by the same bug or feature, depending how you look at it.

Re: The real reason for large DDoS attacks? It's IP Spoofing, not memcached

#5
post #2

>Let's take a deep breath and discuss why such large DDoS attacks are even possible on the modern internet. Because all traffic is treated at face value and not deep filtered and throttled according to some company's whims. Cloudflare wants to change this. Cloudflare wants centralization. Cloudflare wants blacklists.

Is egress filtering really that egregious?

Re: The real reason for large DDoS attacks? It's IP Spoofing, not memcached

#6
post #2

>Let's take a deep breath and discuss why such large DDoS attacks are even possible on the modern internet. Because all traffic is treated at face value and not deep filtered and throttled according to some company's whims. Cloudflare wants to change this. Cloudflare wants centralization. Cloudflare wants blacklists.

The status quo already leads to centralization and gives Cloudflare a tremendous market.

Re: The real reason for large DDoS attacks? It's IP Spoofing, not memcached

#7
post #5
post #2

>Let's take a deep breath and discuss why such large DDoS attacks are even possible on the modern internet. Because all traffic is treated at face value and not deep filtered and throttled according to some company's whims. Cloudflare wants to change this. Cloudflare wants centralization. Cloudflare wants blacklists.

Is egress filtering really that egregious?

No, it's not. It's just time consuming. If you're a large ISP with several disconnected IP subnets, then it's hard to get right.

Re: The real reason for large DDoS attacks? It's IP Spoofing, not memcached

#8

Are there any valid technical use-cases for IP spoofing? i.e. setting the source address of a UDP packet as one outside the originating network? For example, on the server side, BGP hijacking and anycast routing are enabled by the same bug or feature, depending how you look at it.

There are probably legitimate uses. It seems to me that the abuses far outweigh the legitimate uses, though...

Re: The real reason for large DDoS attacks? It's IP Spoofing, not memcached

#9

Are there any valid technical use-cases for IP spoofing? i.e. setting the source address of a UDP packet as one outside the originating network? For example, on the server side, BGP hijacking and anycast routing are enabled by the same bug or feature, depending how you look at it.

> Are there any valid technical use-cases for IP spoofing?

Testing?

Re: The real reason for large DDoS attacks? It's IP Spoofing, not memcached

#10
post #7
post #5

Earlier quoted context omitted.

Is egress filtering really that egregious?

No, it's not. It's just time consuming. If you're a large ISP with several disconnected IP subnets, then it's hard to get right.

This is quite an over simplification but a large amount of the filtering, if placed close to the client, is a single line of config.

"ip verify unicast source reachable-via rx" in the Cisco world.

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