Let's say you want to perform an https request to a certain website but you have a proxy on the middle.
The aforesaid proxy doesn't look into the request but just relay all the traffic to the actual HTTPS server after the user-agent has used the HTTP CONNECT method (as in http://www.web-cache.com/Writings/Internet-Drafts/draft-luotonen-web-proxy-tunneling-01.txt).
Now my question is the following: after the proxy opens a SSL connection to the destination webserver, should it also upgrade the socket which handles the connection with the client to SSL as well? And if so, how would it forward packets to the server without sniffing the actual content?
What I mean here is that if the proxy actually reads data from SSL client socket and forwards them to SSL server socket, the data will be not encrypted to it.
The proxy has a plaintext connection open to the client, via which it received the CONNECT command. It opens a plaintext connection to the server. Thereafter it just copies bytes in both directions. The bytes coming from both client and server are SSL, so this works without the proxy knowing what's inside the ciphertext.
Related
As I understand it Virtual Hosts work in HTTP servers by receiving a HTTP request from the client and examining the Host header, which contains service1.example.com or service2.example.com, etc. and then forwarding the request based on some rules in the HTTP server configuration.
But as I understand it TLS works as follows:
Client opens connection to server.
Client and server have a handshake where the client checks the server's certificate is valid for the name the client is trying to access.
Client transmits the request.
Server transmits the response.
These two seem like they would be incompatible, the server doesn't know which TLS certificate to present to the client until after the request has been sent, but the client won't send the request until the handshake is completed.
They clearly aren't incompatible, I have run web servers with multiple separate TLS virtual hosts each with completely separate certificates. Where have I gone wrong here?
I have the following model that i drew below:
I have a number of processes running on the server. I want nginx or apache to direct the incoming clients through port 80 to one of the server processes to handle the requests. However each connection also establishes a websocket connection to the same process. This is currently initiated from the client side within javascript. At the moment for testing purposes I pass the port within the html rendered on the client. The client then takes this port and estabilishes a websocket connection to the same port that handled its request.
Moving forward to an nginx or apache envionment would it be possible not to pass the port value to the client and have nginx or apache know where it directed the incoming client and use the same port for the websocket connection?
This would have the benefit on not opening all the server ports 8000, 8001, 8002 in the diagram below to the public.
I have built an application called Tun2Socks GUI. It's program to make Socks proxy o be transparent.
Usually it use SSH port forward or TOR as SOCKS service, but I want it can use HTTP proxy too. So I build SOCKS5 proxy my self that connect to that HTTP proxy. It's working good with capturing HTTP request from client to be sent to HTTP Proxy.
The problem when the client send SSL request, I cannot capture the request to be forwarded. How the best method to make SSL request from SOCKS proxy through HTTP Proxy?
Schema of request transportation like here :
Client SSL request > SOCKS Proxy > HTTP Proxy > Internet
Thanks
When a client intentionally wants to establish an SSL session with a target server through a proxy, it does not establish an SSL session with the proxy itself. The client first tells the proxy to establish a connection to the target server, and THEN the client initiates an SSL session with the target server. In that situation, it is not possible for the proxy to sniff the traffic as it is encrypted, nor should it be trying to. A proxy is just a pass-through, it exchanges raw data back and forth between client and server as needed. The proxy should not care what kind of requests the client is sending, since the client tells the proxy where to connect.
If you have injected your proxy in between the client and server in such a way that the client has no knowledge that your proxy exists, the client will not know that it needs to adjust its requests to make them proxy-friendly. The client will be connected to your proxy but it will think it is connected to the target server, and thus will initiate an SSL handshake that your proxy will have to respond to. Only then will your proxy have access to the client's request data (provided the handshake is successful, such as if the client does not verify peer certificates), and can then tunnel the unencrypted data to the next proxy as needed.
Update: I just thought of another scenario that should work for both cleartext and SSL connections. Regardless of whether you are transparently redirecting the client's outbound connection to your SOCKS proxy without the client knowing about it, or the client intentionally connects to the SOCKS proxy and tells it where to go, the SOCKS proxy knows the client's target host/IP:port. The SOCKS proxy can either connect directly to the target, or it can connect to the HTTP proxy and ask it to create a tunnel to the target via the HTTP CONNECT method. If successful, the client has a viable connection to the target, and any data the client sends, SSL or otherwise, will flow as-is to the target, and vice versa. Neither the SOCKS proxy nor the HTTP proxy needs to know anything about the client's request other than the target host/IP:port. That is in the initial SOCKS request, either captured from the intercepted TCP header, or explicit from the client.
I just read over node-tls-proxy (http://code.google.com/p/node-tls-proxy/), a https proxy. I like the idea of it, but I'm not getting why this proxy needs a local http server (see the local-proxy.js script).
So I was wondering if this is necessary?
My idea of the proxy was actually like this: Client -> HTTPS Connection to trusted Server/Proxy -> Internets
In this case network sniffing between the Client and the Server wouldn't (hardly) be possible because it would be ssl encrypted.
Thanks,
Seb
If I get the idea correctly, the goal is to set up a "remote" proxy in a location that one trusts to be secure. Your client shall only communicate with this remote proxy using TLS, the remote proxy is then allowed to do the actual (no longer encrypted) HTTP requests.
What you do on the client side now is this: you configure the "local" proxy in your browser. Since you type "http://..." in your browser even when using the proxy, your browser will initiate an unencrypted HTTP connection to the local proxy first. Then the local proxy will open an encrypted TLS connection to the remote proxy and forward your request over a secured channel.
This means you need the local proxy for the purpose of "transforming" HTTP into HTTPS requests because your browser will dutifully only use HTTP when asked to make an actual HTTP request.
I was wondering if When using PROXY, does SSL (through HTTPS) secure the connection from the admins of the proxy, so they will not be able to see the content?
Basically, when doing SSL connections with a proxy, you connect to the proxy and use something like the CONNECT HTTP verb, which just asks the proxy to connect to the remote host on the specified port. At that point, you're not secure; you can assume that the proxy is listening to the conversation. You then start an encrypted session with the remote host, using that host's public key, or rather the remote host uses its private key which you can check against its public key without needing to trust the proxy. The handshake algorithm is such that the proxy can't see what's inside the encrypted channel (since they don't know the session keys that each side picked as part of the SSL protocol). All the proxy can do is inject random detectable noise or cause the connection to get dropped; they can do denial-of-service attacks but can't affect the integrity or secrecy of any information actually transferred.
That's the beauty of using a proper crypto protocol like SSL.