Doxx/Darkflare: DarkFlare TCPoCDN (TCP over CDN)

157 pointsposted 2 months ago
by josephscott
(github.com)

33 Comments

ignoramous

2 months ago

You could straight up connect to the destination (over TCP) from Cloudflare without needing relays; a project I wrote demonstrates TCP over HTTP (for Deno Deploy) and TCP over WebSockets (for Workers): https://github.com/serverless-proxy/serverless-proxy

Proxying projects utilising HTTP/TLS are popular in the anti-censorship community (discussion board: https://github.com/net4people/bbs) and there are many variants of it; ex:

- KCP (over UDP): https://github.com/xtaci/kcp-go

- Bepass: https://github.com/bepass-org/bepass-worker

doxx9999

a month ago

Yeah, but websockets are limited. I wrote this to tunnel VPNs over this and have full IP connectivity... which does work. A lot of users of the application I have talked with are from China and Iran. Seems to work well.

est

2 months ago

> Services like Cloudflare, Akamai Technologies, Fastly, and Amazon CloudFront ... support millions of websites across critical sectors, including government and healthcare, making them indispensable

The author is pretty naive. There is a reason why Google was left out of the list, in the 2010s people argue "Google is too important and China never dare to block it" then google's whole IP range is blocked.

Amazon Cloudfront, Akmai, Fastly are also (partially) blocked and barely working.

IMHO cleve tricks like "domain fronting" is just freebooting

doxx9999

a month ago

This works on ANY CDN... I focused on Cloudflare because they provide free accounts and it's pretty robust.

dlenski

2 months ago

> IMHO cleve tricks like "domain fronting" is just freebooting

What do you mean by "freebooting"?

We added domain fronting support to the OpenConnect TLS-VPN client _in 2022_ because it is still working and useful for many people working in censored countries and environments. https://gitlab.com/openconnect/openconnect/-/merge_requests/...

est

2 months ago

> because it is still working

That's a big "still" and you don't loose anything in case the real owner of the "fronted" domain suffers loss.

notpushkin

2 months ago

I don't think it's right to assign blame here to any party other than the authoritarian regime that decides to block the whole CDN.

novakwok

2 months ago

There seems another way to achieve this, using Cloudflare's own cloudflared tunnel.

Install a cloudflared tunnel on your remote server, configure it to forward traffic to that server's hosts proxy server(maybe Shadowsocks) using Zero Trust dashboard, and run the following command on your local computer:

cloudflared access tcp --hostname some.your-domain.tld --url localhost:8080

Then localhost:8080's traffic will be forwarded to cloudflareds' host, the whole traffic is using HTTP2 so might look legitimate to Firewall.

For example if using Shadowsocks on server, your Shadowsocks's local client can connect to localhost:8080 as server to forward traffic.

ameshkov

2 months ago

I made a similar thing once to relay UDP traffic over WebSocket and it supports Cloudflare if needed: https://github.com/ameshkov/udptlspipe

The use case is to relay WireGuard over TCP/CF in a restrictive network, confirmed to work in China, obviously not too fast.

tomsonj

2 months ago

chisel is a similar tool in this space https://github.com/jpillora/chisel

I don’t get why headers and requests need to be spoofed if all traffic is over https?

mhio

2 months ago

The headers are seen by the monster-in-the-middle CDN.

It's obfuscation at best. I'm not sure the encrypted traffic will look particularly php-ish for example. Compressed formats might look vaguely passable.

I can't see any stenography code or libraries in the repo.

tomsonj

2 months ago

yeah if the CDN is not trusted this tool won’t help but then little would

duskwuff

2 months ago

> I don’t get why headers and requests need to be spoofed if all traffic is over https?

Because the traffic is to a CDN endpoint (like Cloudflare) which expects it to be a HTTP message.

tomsonj

2 months ago

it can still be an https message, who cares what the path, query string, or headers look like? that is all encrypted

Titan2189

2 months ago

> I don’t get why headers and requests need to be spoofed if all traffic is over https?

https://en.wikipedia.org/wiki/Deep_packet_inspection

fragmede

2 months ago

how are they looking inside the packet if it's encrypted?

sodality2

2 months ago

DPI doesn't have to decrypt it to make certain guesses about its content. For example, timing information, packet sizes, routing info, etc could lead you to believe it's certain kinds of things (SSH, VPN, etc).

coretx

2 months ago

Because SNI. Also, State (sponsored) Actors are certificate authorities. HTTPS is the biggest scam in internet history. https://en.wikipedia.org/wiki/Server_Name_Indication

astrange

2 months ago

This certainly was an issue but it's solved by ECH/DoH. As long as they aren't blocked on your network anyway.

> Also, State (sponsored) Actors are certificate authorities.

To generate a fake certificate as a CA you have to either put it in the Certificate Transparency log, in which case everyone will notice, or don't, in which case browsers will notice (they know what top sites' certificates are supposed to look like) and your CA will get shut down.

hamilyon2

2 months ago

Someone should really test it, real red team black hat style and then fully publish the results. Try to mitm https with real unlogged certs and see what happens. Preregister the whole fully detailed procedure on blockchain. And report to public results fully, with proofs of being caught.

account42

2 months ago

SNI doesn't expose headers and request paths.

peter_d_sherman

2 months ago

>"Why CDNs?

Services like Cloudflare, Akamai Technologies, Fastly, and Amazon CloudFront are not only widely accessible but also integral to the global internet infrastructure. In regions with restrictive networks, alternatives such as CDNetworks in Russia, ArvanCloud in Iran, or ChinaCache in China may serve as viable proxies. These CDNs support millions of websites across critical sectors, including government and healthcare, making them indispensable.

Blocking them risks significant collateral [commercial, commerce] damage, which inadvertently makes them reliable pathways for bypassing restrictions."

(There's also TCP/IP (Internet) via HAM radio (packet radio) and/or StarLink (or more broadly, satellite Internet)...)

Observation: If a large enough commercial corporation has an interest relating to commerce (in whatever area), then if that commerce conflicts with a government block (foreign or domestic) of whatever sort, then the large commercial interest, given enought time, will usually (*) win (they can usually hire better Lawyers, foreign or domestic...)

(*) But not always...

mschuster91

2 months ago

> There's also TCP/IP (Internet) via HAM radio (packet radio)

I get the idea and the spirit behind using ham radio to evade censorship, but...

- you're not allowed to run encrypted content over ham packet radio, at least by regulations, plain HTTP is fine but anything SSL is not... don't be a dick and ruin the fun for everyone else.

- ham radio comms is, outside of emergencies such as widespread blackouts or natural disasters, supposed to only be between ham radio operators themselves - no message-passing for others.

- at least in the long-range bands that you'd actually use for cross-country communications, bandwidth is scarce - and you may disturb a lot of people by doing that, or by just blasting around with huge transmitters... Monday late evening in Germany, try to listen in on 80m, there's so damn many Russians on there with extremely powerful transmitters.

Ham radio frequencies are scarce enough as it is and politicians, particularly in authoritarian countries, already aren't happy about it (in North Korea, for example, it's banned and it's one of the rarest countries to DX with). Please don't make life for hams more complex than it already is by abusing what it stands for.

Melatonic

2 months ago

Packet radio is also extremely slow - this seems like a terrible option.

buremba

2 months ago

Is there any tool that does the other way around? I simply need an alternative to cloudflared tunnel (https://blog.cloudflare.com/tunnel-for-everyone/) for exposing localhost port to a public domain that lets me supports anonymous clients. All cloud solutions charge based on users so they unfortunately doesn’t work

freeone3000

2 months ago

Have you considered upnp+dyndns?

theblazehen

2 months ago

How does this differ from tunneling a VPN over something like wstunnel?

We've been running that in prod for several years without any issues, also going through cloudflare

doxx9999

a month ago

Websocket is a protocol that when used it's rather obvious what you're doing. This is designed to look like actual web traffic.

tripplyons

2 months ago

Reminds me of how people forward requests through CloudFlare workers as a cheap way to get around IP-based rate limits.