Is it possible to authenticate a web browser using an ssl certificate.
Say i store a private key in my application, is there any way to read a key from a browser and try to authenticate based on that?
You can authenticate a browser/user using SSL/TLS client-certificate authentication.
The client certificate must be requested by the server, so you'd need access to the server configuration (not just installing some PHP code on a shared server). This is done at the SSL/TLS layer (in fact, the mechanism is not specific to HTTPS): the server requests the client-certificate during the SSL/TLS handshake (sometimes via a renegotiated handshake). In Apache Httpd, this is typically done via SSLVerifyClient (although you'll need to specify other options too).
The server will then verify the certificate against the CAs you've configured it with (possibly your own, and possibly independent of the CAs used for the server certificate itself). (Alternatively, you could disable certificate verification at the server level in some cases, and have the PHP application do it, but this is a bit more advanced and you'd need to know what you're doing.)
You can access the client certificate from your application and obtains its Subject DN (or alternative names), to identify the client.
It's not clear whether you're after identifying a browser or a user. In the end, everything goes through the browser anyway, but client certificates tend to be allocated to users. Users would have to install that certificate into their browser.
EDIT: For further details, it would help if you could clarify your question and what you intend to do with this.
Is it possible to authenticate a web browser using an ssl certificate.
Say i store a private key in my application, is there any way to read
a key from a browser and try to authenticate based on that?
Firstly, strictly speaking, there's no such thing as an "SSL certificate", since multiple types of certificates can be used for SSL/TLS, and some of these same certificates can also be used for other purposes than SSL/TLS. Typically, "SSL certificate" means "X.509 certificate in the context of SSL/TLS".
Therefore, authenticating a web browser using an SSL certificate implies doing it at the SSL/TLS layer. (There have been attempts to implement message-level security using X.509 certificates at the HTTP layer, but they're not widely supported by browsers.)
Secondly, the private key is held by the remote party that you authenticate. The local party that authenticates the remote party doesn't see any private key. If you (as a server) want to authenticate a web browser, it's the browser that needs to have the private key, not your (presumably PHP) application. In this context, it's not quite clear why your (PHP?) application would have/need a private key if it's the browser that you want to authenticate.
What your verifying application may need (if it's not done by the server itself) is a CA certificate to be able to verify the client certificate it is presented with (or at least some form of trust anchors with which to verify the client certificate). There's no private key required here, just public keys and certificates, unless you want your application to be a CA too.
Indeed, you could have your application be a mini CA. It could make the browser generate a key-pair and send a certificate request to the server (there are mechanisms to have a web page make the browser do all that). Then the server would generate the certificate and make the browser import it back against its private key. Subsequently, the browser could use this certificate for authentication with that server (or other servers that would recognise these certificates).
No, you cannot do that.
There is some development going on, and a few day ago W3C has made a proposal for a encryption standard.
You can however put a key in a cookie and use that to identify. This is the default PHP session id behavior.
Related
i'm trying to figure out if the following case makes any sense.
Background info
I'm building a PHP platform that makes a lot of REST API calls via Guzzle. I really need to make sure that connections are valid so apart from API authorization, NAT firewalls and valid HTTPS/SSL connections i also want to build some checks in our application. For instance i am also validating that connections come from the valid IP subnets provided by the API service.
The problem
Then i started looking at the SSL certificates provided by the API services we're using. Offcourse the security is based on public/private keys and i cannot see the private keys used by this service but what i could do is make sure the public certificate(s) are still the same as the ones i could store locally.
Now i don't know if that makes any sense or not? My presumption here is that certificates for these organisations will only change once every two years. And i know that it doesn't validate anything, because i don't own the private key, but still, it is an extra check.
Practical
Then there is the practical side, is it even possible, using the openssl s_client i am able to get the certificates used by the API. But the verify option that Guzzle is providing is based on a .PEM file and that uses private keys right?
// Use a custom SSL certificate on disk.
$client->request('GET', '/', ['verify' => '/path/to/cert.pem']);
So is it even possible in Guzzle or basic CURL and would it make any sense or would that just be a false sense of security?
The service provider's public key allows you to do two things:
Send encrypted data that only the service provider can decrypt and no one else.
Once the encrypted connection is established, you know for sure that the messages sent back by the service provider originates from no one else than the service provider.
No one will ever provide their private key. That would defeat the purpose of a key being private. However, the whole idea of a certificate is to provide a public key signed by a trusted root certification authorities such as Verisign. Such trusted root authorities come pre-installed on your O.S. or are added by the system administrator.
If someone manipulates DNS so as to misguide you to connect to a fake host, the encrypted connection will not be established because the fake server will not be able to decrypt your messages as he does not have the proper private key.
You do not need to store anything. Upon connection, being presented with a certificate, you can verify the validity on the fly: as previously explained, if the certificate has been issued by a trusted root certification authority stored and trusted on your machine, you are good to go.
I have a SSL enabled eCommerce website which uses cURL for payment processing. Everything is running well but recently I learned about "CA Public Certification Bundle for cUrl" that its a good idea to use it for cURL connections.
If this is true than can someone tell me how or how is it better/different than using the standard SSL?
Doesn't the SSL already provide some kind of certification for all connections?
Any HTTPS client connected to an HTTPS server will get its certificate (in fact, it can be a certificate chain). This server certificate must then verified by the client to authenticate the server.
This is normally done by using a number of CA certificates that are configured on the client as trust anchors (i.e. this is what you trust in advance, before encountering the server certificate). The client tries build a chain between the last element of the server chain and one of the CA certificates in its trust anchors. If there is such a valid chain the server certificate is trusted.
A "CA certificate bundle" would be a set of trust anchors. You can build your own by looking for CAs you're willing to trust, or you can use an existing bundle. Most OSes or browser come with an existing bundle. cURL in itself doesn't but it can rely on a pre-defined location (set at compile time) or it also suggests to use the Firefox bundle (via a conversion mechanism). (You can override default setting via extra options, on the command line or via the API.)
Certificate Pinning (which you also mention) has nothing to do with a CA cert bundle. In fact, it's almost the opposite. Instead of relying on 3rd party trust anchors (the certification authorities), you explicitly "pin" a set of server certificates you know as directly trusted. They're not used to verify other certificates, instead, you compare the certificate you get with the exact certificate you're expecting for that host (or at least you compare public keys). This is more like having a reference mapping from server name to certificate (or to public key) and comparing what you get from that host with the reference you have. Of course, this can only work for a reasonably small set of certificates in practice, unlike the CA (PKI) approach which is designed to let you authenticate parties you have never encountered before (via a 3rd party: the CA).
How is it better/different than using the standard SSL?
Doesn't the SSL already provide some kind of certification for all connections?
Using a CA certificate bundle isn't different than using "standard SSL", it is what's commonly used for SSL/TLS connections. You often don't see it because that CA bundle is often supplied with your client (or with the OS).
Note that strictly speaking, this is orthogonal to SSL/TLS itself, which mainly just says you should authenticate the server. Certificate verification (the PKI way, via CA certificates) is defined in a different specification, also complemented by a specification on how to verify the name in the certificate (and the HTTPS specification of course).
Found a great answer here. The comment above really helped. The exact keyword I was looking for was "Certificate Pinning".
I have a JavaFX-2.2 application, that uses a webengine to load some php and html pages from a web server. My application and the web server are not in the same machine. My login php page uses a self-signed certificate. In my client side where the webengine is, i want to connect to that php using the client certificate which is signed by the same CA, as the server's certificate. I want with that way, only my application to have access to the servers pages.
I have read the webengine api but i have not found yet a way to do so. Also a google search returns a few lemmas .
Can i do that?
Thanks in advance
You may be able to add one but every time a visitor visits your site, it will show the "This site's security can not be trusted" page.
As I understand you want to use SSL authorization.
1. Your server signed as server.
2. Your application signed as client.
Only both sign can connect. No other servers, no other clients.
In that case you must integrate server public key in client. And client public key in server. (different API and methods use for it) almost all language and servers work fine with SSL authorization.
You can use Self signed keys, or you may generate free pair here: www.startssl.com
Here's the situation:
I'm working on an open source web application (in PHP) that will be distributed to domain owners (abbit like WordPress).
Now I (my server) needs to communicate with my users (users server). I'm going to be using cURL to transfer data between servers (using POST).
The only problem is, I have a SSL certificate, but the users won't have one. So the users server will be able to talk to my server without some evil b***** eavesdropping, but my server will not be able to talk to my users server, securely.
And I certainly do not want to require users to purchase SSL certificates in order to use the application.
I was wondering if there is a way to get away with only using one SSL certificate and still manage to POST data to and from securely?
I'm also open to any alternative suggestions.
Thanks!
You can post a request to call your server back (and pass some unique ID of the data to be requested from your server), so that servers connect to your server as clients, pass the ID and get their information.
The question, though, is what you need the certificate for. If you want to authenticate those servers (or ensure that your data only reaches legitimate servers), then you need those servers to have valid certificates (BTW They are not called SSL certificates, the naming is wrong). Otherwise spoofing the server is easy.
I have following scenario:
The Android clients communicate with a PHP server via HTTP Post. The PHP server is communicating with mySQL database and sends the output as JSON to the Android client.
Now I am concerned that people sniffing the traffic, find out the URL and will post a lot of grap in my database.
I have no concern of sniffing the payload. So it does not necessarily be encrypted.
I was thinking of TLS/SSL which comes in mind because of the HTTP connection. But I am not sure what is the prefered way to go in this scenario.
What you want to do is employ mutually-authenticated SSL, so that your server will only accept incoming connections from your app and your app will only communicate with your server.
Here's the high-level approach. Create a self-signed server SSL certificate and deploy on your web server. You can use the keytool included with the Android SDK for this purpose. Then create a self-signed client and deploy that within your application in a custom keystore included in your application as a resource (keytool will generate this as well). Configure the server to require client-side SSL authentication and to only accept the client certificate you generated. Configure the client to use that client-side certificate to identify itself and only accept the one server-side certificate you installed on your server for that part of it.
If someone/something other than your app attempts to connect to your server, the SSL connection will not be created, as the server will reject incoming SSL connections that do not present the client certificate that you have included in your app.
A step-by-step for this is a much longer answer than is warranted here. I would suggest doing this in stages as there are resources on the web about how to deal with self-signed SSL certificate in Android, both server and client side. There is also a complete walk-through in my book, Application Security for the Android Platform, published by O'Reilly.
SSL won't help you, as the traffic can be sniffed before the data hits the wire, and people will STILL be able to figure out your API calls and fill the DB with crap.
You can "secure" the service with access tokens and username/password requirements. But again, they won't prevent a malicious user from flooding your system with bad data. However, it would let you track down WHICH user was doing so, as they'd have to be using a unique access token of some sort to get at your system.