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GitHub under ongoing DDoS attack

status.github.com

211–220 of 352 posts

Re: GitHub under ongoing DDoS attack

#211
post #58

Out of curiosity, would Cloudflare be able to sustain the amount of inbound requests they're handling?

L7 attacks come down to how much you can cache. If GitHhub was a purely static site, they wouldn't have trouble serving the requests themselves in any case.

Github can solve this problem with CloudFlare to the same extent that Github's product can be replaced with a hundred nginx servers with 10Gbit uplinks, large RAM caches, and effectively zero CPU time spent on each request.

Re: GitHub under ongoing DDoS attack

#212

I wonder what happened if Google put Baidu Ad javascript into the Safe Browsing list...

I think they should: traffic through the Great Firewall of China has been compromised, it's getting injected with malware and therefore cannot be trusted.

Browsers and all safe browsing software should treat any traffic through the Great Firewall of China as malicious and show a scary warning in your browser asking to confirm before going there.

The drop of traffic to Chinese servers and therefore customers would create such a big outcry it might make them stop.

Re: GitHub under ongoing DDoS attack

#213
post #118

Earlier quoted context omitted.

SYN Flood is already mitigated a long time ago with SYN cookies. The rest ..... well, it's basically just packets. I see this latest development as good news. The Javascript MITM trick was very clever because forcing github to render and serve a page is a lot more resource consuming than just firing packets at servers that ignore them (like a UDP or SYN flood). The latter can saturate network links until the sources…

> well, it's basically just packets Is "DNS flood" a DNS reflection attack though?

Usually no.

There are generally two types of floods against DNS infrastructure:

- Flood of "valid" requests, to a large number of open DNS recursors. To avoid caching they usually contain random prefix. Flood against large number of open DNS recursors basically causes the recursors to not work, and many authoritative servers to be overwhelmed.

- Flood directly against authoritative servers, to fill the network or use up all the CPU.

Traditional reflections aren't that popular any more.

Re: GitHub under ongoing DDoS attack

#214
post #130

Earlier quoted context omitted.

"Bully" is rather too weak a label for the perpetrator. This attack is criminal. If carried out by a sovereign nation, perhaps an act of war. We don't allow foreign raiding parties to enter our country to loot private businesses. Neither should we treat this attack as a simple act of "bullying". GitHub should get the full support of federal law enforcement, if not the military.

> perhaps an act of war > GitHub should get the full support of federal law enforcement, if not the military. Are you sure you wanna go there? Think it through ;) Don't let me stop you though. Den Haag is lovely this time of year and I have this thing I want to talk over with you guys anyway.

This goes well into flamewar territory. Please stay on topic and be civil.

Re: GitHub under ongoing DDoS attack

#215
I must say I wonder a lot of the volume of generated traffic. Is that hundreds of connections? Thousands? Millions? What is the number of unique IP's hitting them, bandwidth, etc.

Does anyone have any data on that?

Re: GitHub under ongoing DDoS attack

#216

Why are there so many condescending comments about "saving the Chinese people". Ask yourselves, are you really qualified to judge the Chinese people? Have you been to China? Have you been to different parts of China? What are the main sources that you obtain news? Are you reading the "assumptions" over and over again until they are "assumed" as facts? I liked this place when it used to be just about technologies.

HN was never just about technology, for the same reason hackers don't only hack. That's part of what makes it so great.

Re: GitHub under ongoing DDoS attack

#217
post #58

Out of curiosity, would Cloudflare be able to sustain the amount of inbound requests they're handling?

Is there any data on the size of the traffic?

Anyway, even assuming the traffic is infinite, (to my understanding) most of the flooding IP's are from china. If that's the case it would most likely only affect the datacenter handling Chinese traffic. So even if it's really bad, only a (relatively small)[1] part of the world would notice.

[1] relatively small in terms of the size of internet, not number of people

Re: GitHub under ongoing DDoS attack

#218

From looking at the Javascript injection code ( http://www.theregister.co.uk/2015/03/27/github_under_fire_fr... ) it seems like the quality of the script is pretty amateur. They inject jQuery not once, but twice, and only use jQuery to make a simple XHR request. Perhaps they are worried about one instance of jQuery being taken down or made unavailable to them, but they really don't need jQuery at all for something th…

the jQuery is being injected from 2 different sources. The first being from a Baidu CDN, I suppose they anticipate some kind of attack on Baidu and included the 2nd one as fallback.

As for jQuery being unnecessary for this job; agreed, but hey, it got the job done.

Re: GitHub under ongoing DDoS attack

#219

Earlier quoted context omitted.

Nullifying DDOS doesn't take ingenuity, it takes a big wallet, which Github no doubt has, but let's not pretend that its some engineering feat. If it was, a small company being ddosed would have a chance at fending it off all the same, but that's just simply not the case.

I'm not well-versed in the technical details of defending from DDOS, but unless it's a mathematical NP-complete problem, they have a chance.

Honestly, if you start by saying you're not well versed, how can you confidently make a statement about whether it is possible or not?

Large scale DDOSes are usually the most damaging when they're high bandwidth (Layer 7 attacks can usually gradually be mitigated by well written firewall rules placed on the proximity of the network). When a DDOS is just maxing out the bandwidth coming into your network or sometimes even data center, no amount of clever algorithms can make your pipes bigger. For that, you need money.

*edit fixed a minor typo

Re: GitHub under ongoing DDoS attack

#220

Earlier quoted context omitted.

Nullifying DDOS doesn't take ingenuity, it takes a big wallet, which Github no doubt has, but let's not pretend that its some engineering feat. If it was, a small company being ddosed would have a chance at fending it off all the same, but that's just simply not the case.

I'm not well-versed in the technical details of defending from DDOS, but unless it's a mathematical NP-complete problem, they have a chance.

It can be a weakness in a widely deployed, vital protocol and that would be technically impossible to fix- not because of the technology but because altering the protocol would either require everyone on the Internet to change their software, or it'd preclude certain types of communication, or both.
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