If a client is requesting a domain that does not have a valid CA signed certificate and the server not intend on supporting HTTPS but does support HTTP for this domain, what is the best way to handle this in the web server. Note, the server does handle requests for SSL (HTTPS) on other domains so it is listening on 443.
Example where this would apply is for multi sub-domains where the sub-domains are dynamically created and thus making it extremely difficult to register CA signed certificates.
I've seen people try to respond with HTTP error codes but these seem moot as the client (browser) will first verify the certificate and will present the hard warning to the user before processing any HTTP. Therefore the client will only see the error code if they "proceed" past the cert warning.
Is there a canonical way of handling this scenario?
There is no canonical way for this scenario. Clients don't automatically downgrade to HTTP if HTTPS is broken and it would be a very bad idea to change clients in this regard - all what an attacker would need to do to attack HTTPS would be to infer with the HTTPS traffic to make a client downgrade to unprotected HTTP traffic.
Thus, you need to make sure that the client either does not try to attempt to access URL's which do not work properly (i.e. don't publish such URL's) or to make sure that you have a working certificate for these subdomains, i.e. adapt the processes for creation of subdomains so that they not only have an IP address but also a valid certificate (maybe use wildcard certificates).
Considering these websites don't have to work with SSL, the webserver should close all SSL connections for them in a proper way.
There is no canonical way for this, but RFC 5246 implicitly suggests to interrupt the handshake on the server side by using the user_cancel + close_notify alerts. How to achieve this is another question, it will be a configuration of the default SSL virtual host.
user_canceled
This handshake is being canceled for some reason unrelated to a
protocol failure. If the user cancels an operation after the
handshake is complete, just closing the connection by sending a
close_notify is more appropriate. This alert should be followed
by a close_notify. This message is generally a warning.
If you are dealing with subdomains, you probably can use a wildcard certificate for all of your subdomains.
Adding the CA certificate to your client will remove the warning (that's what companies do, no worry).
When hosting with Apache, for example, you can use VirtualDocumentRoot to add domains without editing your configuration. Have a look at the solution provided here : Virtual Hosting in SSL with VirtualDocumentRoot
Related
I've some discussion with my colleague whether we can make HTTPS connection without using SSL certificate. I'm quite confused about this. Can anyone explain this?
It's not possible to do HTTPS connections without SSL. The way it works is complicated and as mentioned in the comments there is a great answer here.
But to summarize the reason why it's not possible:
HTTPS needs an SSL certificate, you can think of SSL as the S in HTTPS, since the secure connection is made using the certificate. A client sends a request to a server, they do a secure handshake (which requires the certificate in order to create and verify the keys) and then proceed to business as usual.
Any browser will throw a million red flaws if you try to circumvent this behavior. You could trick your own server to believe data is coming as HTTPS rather than HTTP in some cases (if you have control over it), but you won't be able to fool browsers.
Is there a posibillity to check if a remote server supports https?
Currently im requesting https, if it doesnt work retry http and then display an error if this still does not work.
Is there a feature embedded in HTTP which indicates if https is supported?
By this I dont mean redirect etc. because these must be implemented on the server and arent always.
Silently falling back to HTTP sounds dangerous. An attacker (i.e. man-in-the-middle) might be able to force you to use the insecure channel by blocking your requests to HTTPS. Thus, I would not recommend this approach in general.
In general, you should let your users decide which protocol to use. If they specify https, you should not silently downgrade but throw an error. If they specify http however, it might be possible to also try https first and silently fall back to http if that fails (since they requested http in the first place).
An a general answer to your request: you can only try https to check if the server supports https. There is an HTTP(s) extension called HTTP Strict Transport Security (HSTS) which allows servers to indicate that all requests to them should always be performed via secure channels only. If you receive such a header in a response for an HTTPS request, you can force https in the future for the host. Note though that you have to ignore such headers receive over insecure HTTP.
In general, you can't trust any information you received over plaintext HTTP to give you any indication about security options (such as support for TLS) of the server since this information could be arbitrarily spoofed by man-in-the-middle attackers. In fact, preventing such undetectable changes is one of the main reasons to use TLS / HTTPS in the first place.
I understand that HTTTPS is secured and it requires SSL certificate issued by CA authority to make the application secure. But what I do not understand is that its in-depth difference with HTTP.
My question, as a user, if I make a request to an application with HTTP or if I make same request to HTTPS what is the actual difference? The traffic remains same to both. Is there any traffic filtering happening if I use HTTPS?
Thanks
HTTPS, as an application protocol is just HTTP over TLS, so there are very few differences, the s in the URL and some consequences for proxy, that is all.
Now you are speaking about the traffic and the filtering. Here you have a big difference because using TLS adds confidentiality and integrity: passive listeners will see nothing about the HTTP data exchanged, including headers. The only thing visible will be the hostname (taken from the https:// URL) as this is needed at the TLS level before HTTP even happens, through a mechanism called SNI (Server Name Indication) that is now used everywhere to be able to install multiple services using TLS under different names but with a single IP address.
The question is about HTTP vs HTTPS.
If I want to anonymously load a website that forces HTTPS, like Google.com, do I need an HTTPS proxies, or can I get away with HTTP proxies?
If your proxy is SOCKS it will not care what kind of socket is connecting through it. It has its own handshake and it does not care about what happens after the handshake. Whether after the SOCKS handshake an SSL handshake (HTTPS) is started it is not a SOCKS proxy problem, it will just pass through.
Several HTTP proxies on the other hand expect HTTP headers to guide them, such a HTTP proxy will not allow HTTPS since it needs to read the headers.
On the third hand (ekhm... well, foot?), an HTTP proxy that supports HTTP CONNECT can also setup the transfer of arbitrary data. Therefore such a proxy can setup any type of socket, which can have an SSL handshake, which can then be used for HTTPS transfer.
HTTP Proxy Server supports CONNECT verb which supports HTTPS connections within HTTP Proxy. You don't need special HTTPS proxy server or any other setup.
CONNECT verb allows you to create binary socket tunnel to any given IP:Port address. So any HTTP client (all browsers), will open secure tunnel and communicate securely over proxy server. However, no one cant control or see anything that is going through the tunnel unless they implement man in middle attack by sending you self-signed certificates.
Most firewall these days automatically implement man in middle self signed certificates that are deployed in work network, so you have to probably dig more to identify whether it is really secure or not. So it may not be that anonymous.
If you're trying to access a service anonymously, you won't get this by running your own proxy. It's not clear from the original question what is meant by "proxy", e.g. local service, or remote service. You won't get anonymity by surfing through a proxy that's on your network, unless it's something like a TOR proxy which relays out through the TOR network.
As for whether proxies can support HTTPS or not, that's been covered here, it would be unusual to find a proxy that doesn't support CONNECT. However if it's a remote anonymizing service you're using, I doubt they would do MitM, since you'd need to install the signing cert into your trusted root store, so they couldn't do that surreptitiously.
Wikipedia defines HTTP(S) or S-HTTP as a security layer over HTTP:
Technically, it is not a protocol in and of itself; rather, it is the
result of simply layering the Hypertext Transfer Protocol (HTTP) on
top of the SSL/TLS protocol, thus adding the security capabilities of
SSL/TLS to standard HTTP communications.
Logically, it implies that every feature and aspect of HTTP (e.g. methods and status codes) exists in HTTPS.
Should I expect any caveats or differences when switching an existing HTTP REST interface to HTTPS?
There doesn't seem to be any limitation of what you can do with HTTP but not HTTPS. The only limitations/differences relate to the fact that the connection is encrypted. As Eugene mentioned, this includes the fact that HTTPS cannot be proxy-cached. There are however some caveats:
HTTP inline content inside HTTPS page
If you start using HTTPS for sites where you originally used HTTP, problems might arise with HTTP inline content, e.g. if you use 3rd party HTTP services or cross-domain content:
scripts: google maps API
iframes: other webs, facebook, google ads, ...
images, static google maps, ...
In that case, many browsers will disable the "insecure" HTTP content inside HTTPS page! For the user, it is very hard to switch this off (especially in Firefox).
The only reliable way around that is to use protocol-relative URLs. So, instead of:
<script src="http://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false"></script>
which would break on HTTPS page, you will just use
<script src="//maps.googleapis.com/maps/api/js?v=3.exp&sensor=false"></script>
which will work as HTTP on HTTP page and as HTTPS on HTTPS page. This fixes the problem.
The downside of course is that it is useless encryption of large amount of network traffic, that is not vulnerable and wouldn't normally have to be encrypted. This is the cost of the paranoid browser approach to security (like year ago, there was no warning from FF in this situation, and I was completely happy. World changes ...)
If you don't have signed SSL certificate for your domain
Another caveat of course is that if you don't have SSL certificate for your domain which is signed by trusted CA authority, then if your users will use HTTPS, they will have to pass a terrible scary 4-5 step procedure to accept the certificate. It is almost impossible and unprofessional to expose an average user (unaware of the problematics) to this. You will have to buy certificate in this case. Many times you end up using HTTP instead of HTTPS because of this. So if you cannot afford to buy the certificate, the browser paranoia forces you many times to use insecure HTTP protocol instead of HTTPS. Again, 6-7 years ago, it wasn't the case.
Mixing HTTP and HTTPS - cookie and authorization problems
If you use both HTTP and HTTPS within the same session, you might run into problems because sometimes they will be treated as separate sites (even if the rest of the URL is the same). This might be the case of cookies - in some cases they will not be shared between HTTP and HTTPS. Also, the HTTP authentication - RFC2617 will not be shared between HTTP and HTTPS. However, this type of authentication is now very rare on the Web, possibly due to lack of customization of the login form.
So, if you start using HTTPS, easiest way is then to use HTTPS only.
After several years of running HTTP over HTTPS, I am not aware of any other caveats.
Performance Considerations
HTTP vs HTTPS performance
HTTPS vs HTTP speed comparison
HTTPS Client/Broswer Caching
Top 7 Myths about HTTPS - Note commentary on HTTPS caching that is handled differently in browsers. It's from 2011 though, the browsers might have changed.
Will web browsers cache content over https
More on why there is no HTTPS proxy caching
Can a proxy server cache SSL GETs? If not, would response body encryption suffice?
UPGRADE command in Websockets via HTTPS
While the WebSocket protocol itself is unaware of proxy servers and firewalls, it features an HTTP-compatible handshake so that HTTP servers can share their default HTTP and HTTPS ports (80 and 443) with a WebSocket gateway or server. The WebSocket protocol defines a ws:// and wss:// prefix to indicate a WebSocket and a WebSocket Secure connection, respectively. Both schemes use an HTTP upgrade mechanism to upgrade to the WebSocket protocol.
http://en.wikipedia.org/wiki/WebSocket
As a coder of REST, I do not see any possible caveats when you switch HTTP REST to HTTPS. In times if you find some, you would definitely have them in normal HTTP REST too.