First a bit of background here. This question is for a server not exposed to the wilds of the internet, a private network with no outside networking. Its for QA testing of a product and needs to be tested, so security is a joke. On with the question:
Is it possible to configure Squid3/Samba to only accept NTLMv1 authentication?
I've already built a Squid3/Samba for NTLMv2. But I'm lost on how to configure Squid3/Samba to accept only NTLMv1.
Current Squid conf:
auth_param ntlm program /usr/bin/ntlm_auth --diagnostics --helper-protocol=squid-2.5-ntlmssp
auth_param ntlm children 25
auth_param ntlm keep_alive on
acl ntlm proxy_auth REQUIRED
It's been a while for this. So I'll post my answer. I had to do a strange filter to the system to deny NTLMv2 requests using a Bluecoat/Packeteer hardware. Not much of an answer, but it will close this.
Related
I want to implement proxy server in node.js which is somewhat similar to Charles proxy - it should intercept HTTPS requests from my mobile app, decipher them, route some of them depending on body content to original backend and mock others with some static files.
How this HTTPS stuff is handled in Charles or other proxies?
Will I need self-signed root certificateon mobile device?
Are there any libraries which will help me?
How this HTTPS stuff is handled in Charles or other proxies?
Technically, Charles Proxy or Proxyman.io (the one I'm using now) would do the following steps:
Generate a root certificate and install to keychain and trust it. This steps would do once.
Open the Local Server (at 8888 or 9090).
Override the HTTP Proxy in System to this port. Thus, all traffic will go through the port. You could use the networksetup CLI to easily achieve or Privileged Helper tool on macOS for high performance and secure.
As soon as capture the first socket: If It's a HTTP request, get a first line message. Ex:
GET https://api.producthunt.com/v1/posts HTTP/1.1
Then open the forward socket to this URL.
If it's a HTTPS, make sure do SSL-Handshake and then get the first line message.
Finally, just get the rest of message and parse to proper message(HTTPCParser from NodeJS would be potential candidate)
Send data forward and back from the client and the destination server.
Do manipulation actions if you need since you're the true mitm.
Will I need self-signed root certification mobile device?
Yes, you must install the Root Certificate in the first steps to your iOS device. For the Header/Response detail. Check chls.pro/ssl or proxy.man/ssl from those Charles or Proxyman, and see the content.
You can do it on iOS Simulator by using ADVTrustStore
Are there any libraries which will help me?
You can check the those famous open source to see how it works
- mitmproxy
- zapproxy
- http toolkit
Hope this can help you.
Using Charles Proxy to see your mobile's requests is super easy.
Here is a simple video going over how to set it up. https://www.youtube.com/watch?v=AW2vTBRfOrU
I have a front end web server running over HTTPS - this is public facing - i.e. port is open.
I also have a backend API server that my webserver makes API requests to - this is public facing and requires authentication - port is open.
These 2 servers run over HTTPS.
Behind the API server, there are lots of other servers. The API server reverse proxies to these servers. Ports for these other servers are not open to incoming traffic. They can only be talked to via the API server.
My Question ... Do the "lots of other servers" need to run over HTTPS or, given that they cannot be accessed externally, can they run over HTTP safely instead?
I thought this would be a common question but I could not find an answer to it. Thanks. If this is a dupe please point me to the right answer.
TL;DR you should encrypt the traffic unless it's on the same host.
You can't trust your network. Malwares in your own network can intercept/modify http requests.
It's not theoretical attacks, but real life example:
Routers (probably hacked) inside the network of some websites injecting ads: https://www.blackhat.com/docs/us-16/materials/us-16-Nakibly-TCP-Injection-Attacks-in-the-Wild-A-Large-Scale-Study-wp.pdf
Indian network sniffing between cloudfare and back-end: https://medium.com/#karthikb351/airtel-is-sniffing-and-censoring-cloudflares-traffic-in-india-and-they-don-t-even-know-it-90935f7f6d98#.hymc3785e
The now famous "SSl Added and removed here :-)" from the NSA
The question is how much do you trust the connection between the public IP and the backend server?
If it is not your data center, at least any privileged employee of the ISP could see/change the data. I guess that's not something your customers would like to hear.
If it is your data center, meaning you are a kind of ISP still everybody who has physical access to the data center can potentially sniff the clear text traffic. Or in general, anybody who has access to the wire can see the traffic, it is much harder to implement a strict access control in your company.
I have a windows server 2012 VPS running a web app behind Cloudflare. The app needs to initiate outbound connections based on user actions (eg upload image from URL). The problem is that this 'leaks' my server's IP address and increases risk of DDOS attacks.
So I would like to prevent my server's IP from being discovered by setting up a forward proxy. So far my research has shown that this is no simple task, and would involve setting up another VPS to act as a proxy.
Does this extra forward proxy VPS have to be running windows ? Are their any paid services that could act as a forward proxy for my server (like cloudflare's reverse proxy system)?
Also, it seems that the suggested IIS forward proxy plugin, Application Request Routing, does not work for HTTPS.
Is there a solution for both types of outgoing (HTTPS + HTTP) requests?
I'm really lost here, so any help or suggestions would be appreciated.
You are correct in needing a "Forward Proxy". A good analogy for this is the proxy settings your browser has for outbound requests. In your case, the web application behaves like a desktop browser and can be configured to make the resource request through a proxy.
Often you can control this for individual requests at the application layer. An example of doing so with C#: C# Connecting Through Proxy
As far as the actual proxy server: No, it does not need to run Windows or IIS. Yes, you can use a proxy service. The vast majority of proxy services are targeted towards consumers and are used for personal privacy or to get around network restrictions. As such, I have no direct recommendations.
Cloudflare actually has recommendations regarding this: https://blog.cloudflare.com/ddos-prevention-protecting-the-origin/.
Features like "upload from URL" that allow the user to upload a photo from a given URL should be configured so that the server doing the download is not the website origin server.
This may be a more comfortable risk mitigator, as it wouldn't depend on a third party proxy service. A request for upload could be handled as a web service call to a dedicated "file downloader" server. Keep in mind that if you have a queued process for another server to do the work, and that server is hosted in the same infrastructure, both might be impacted by a DDoS, depending on the type of DDoS.
Your question implies that you may be comfortable using a non-windows server. Many softwares exist that can operate as a proxy(most web servers), but suffer from the same problem as ARR - lack of support for the HTTP "CONNECT" verb, which is used by modern browsers to start an HTTPS connection before issuing a "GET". SQUID is very popular, open source, and supports everything to connect to.. anything. It's not trivial to set up. Apache also has support for this in "mod_proxy_connect", but I have no experience in that and the online documentation isn't very robust. It's Apache, though, so it may be worth the extra investigation.
I have deployed an opnesource public webservice (elasticsearch) on my Ubuntu.
Problem is - no security at all (only if you pay).
I've researched a bit about blocking port only to internal requests while allowing external access only through authentication proxy.
The simplest way was nginx with basic authentication.
But what's the best practice in those cases? What are my other options?
This is question would find a better home on ServerFault, but you're likely going to find that you'll want to use iptables to block all external IPs on all ports, except for the 'authentication proxy'
Sorry if it is a duplicate, as I am not a security nor network expert I may have missed the correct lingo to find information.
I am working on an application to intercept and modify HTTP requests and responses between a web browser and a web server (see how to intercept and modify HTTP responses on server side? for the background). I decided to implement a reverse proxy in ASP.Net which forwards client requests to the back-end HTTP server, translates links and headers from the response to the properly "proxified" URL, and sends the response to the client after having extracted relevant information from the response.
It is working as expected, except for the authentication part: the web server uses NTLM authentication by default, and just forwarding requests and responses through the reverse proxy does not allow the user to be authenticated on the remote application. Both the reverse proxy and the web application are on the same physical machine and are executed in the same IIS server (Windows server 2008/IIS 7 if that matters). I tried both enabling and disabling authentication on the reverse proxy app with no luck.
I have looked for information about it, and it seems to be related to the "double-hop problem", which I do not understand. My question is: is there a way to authenticate the user on the remote application through the reverse proxy using NTLM? If there is none, are there alternative authentication methods I could use?
Even if you don't have a solution to my problem, just pointing me to relevant information about it to help me get out of the confusion would be great!
I found what the problem was (and it is NTLM): in order to have the browser asks the user for its credentials, the response must have a 401 status code. My reverse proxy was forwarding the response to the browser, so IIS was adding a standard HTML code to explain the requested page cannot be accessed thus preventing the browser from asking credentials.
The problem was solved by removing the response content when the status code is a 401.
With all due respect I have for the one that answered that some years ago, I must admit this is plainly false. The problem was indeed solved AFTER removing the response content when the status code is a 401, but it had none to do with the initial problem..
The truth is that windows authentication was made to authenticate people over local windows networks, where no proxy server is present or even needed.
The main problem with NTLM authentication is that this protocol does not authenticate the HTTP session but the underlying TCP connection, and as far as I know there is no way to access it from asp code.
Every proxy server I tried broke NTLM authentication.
Windows authentication is comfortable for an user because he won't ever need to enter your password to whatever application may lie in your intranet, frightening for a security guy because there is an auto-login without even a prompt if the site domain is trusted by IE, shocking for a network administrator because it melts the application, transport and network layer into some "windows ball of mug" instead of just plain http traffic.
NTLM won't work if the TCP packets are not forwarded exactly as the reverse proxy received > them. And that's why many reverse proxy doesn't work with NTLM authentication. (like nginx) > They forward HTTP requests correcty but not the TCP packets.
Nginx has the functionality to work with NTLM authentication. Keepalive needs to be enabled which is only available trough the http_upstream_module. Additionally in the location block you need to specify that you will be using HTTP/1.1 and that the "Connection" header field should be cleared for each proxied request. Nginx config should look something like:
upstream http_backend {
server 1.1.1.1:80;
keepalive 16;
}
server {
...
location / {
proxy_pass http://http_backend/;
proxy_http_version 1.1;
proxy_set_header Connection "";
...
}
}
I scratched my head for quite some time with this issue but the above works for me. Note that if you need to proxy HTTPS traffic, a separate upstream block is deemed necessary. To clarify a bit more, "keepalive 16;" specifies the number of simultaneous connections to the upstream your proxy is allowed to keep. Adjust the number as per the expected number of simultaneous visitors on the site.
Although this is an old post, I just want to report that it works for me quite well with an Apache2.2 reverse proxy and the keepalive=on option. Obviously, this keeps the connection between the proxy and the SharePoint host open and "pinned" to the client<>proxy connection. I don't exactly know the mechanisms behind this, but it works fairly well.
But: Sometimes, my users encounter the issue that they're logged in as another user. So there seems to be some mixing-up through sessions. I will have to give this some further testing.
Solution for everything (in case you have a valid, signed SSL certificate): Switch IIS to Basic Auth. This works absolutely fine, and even Windows (i.e. Office with SharePoint connection, all WebClient-based processes etc.) won't complain at all.
But they will when you're just using http without SSL/TLS, and also with self-signed certificates.
I confirm that it works with "keep-alive=on" on apache2.2
I examined frames with Wireshark, and I know why it doesn't work. NTLM won't work if the TCP packets are not forwarded exactly as the reverse proxy received them. That's why many reverse proxies, like nginx, don't work with NTLM authentication. Reverse proxies forward HTTP requests correctly but not the TCP packets.
NTLM requires a TCP reverse proxy.