I'm using SSL certificates in a client-server application; both the client and the server are using 2 certificates that will expire soon. Normally, you'd just replace the certificates with new ones, but this cannot happen at once because of the huge numbers of clients.
So, if only the servers and a part of the clients are updated, the rest of the clients won't be able to authenticate anymore.
A quick fix is to replace the binaries with a version which simply disregards expiry date of the certificates; the update of the clients can be done sequentially, as long as it will finish before the certificates expire.
Long term solutions I thought about:
use Puppet to push new certificates on clients
unfortunately, not viable because not all clients are/will be managed via Puppet
use a second set of certificates
if first set has expired, use the second one
in this manner, server will have new certificates, a part of clients will have new certificates and the rest of the clients will have old certificates, but everything works
client requests a new certificate from the server, if the current one has expired.
Are there any other solutions?
I assume you use the SSL certificates for an online SSL connection, like HTTPS, or SFTP.
The big question is: Do you still trust and want to use your server-side key! If so you can just re-issue the server certificate with a new expiration date still using the old key and thus extending the lifetime. The question is, if you still trust the old key or if it should be replaced. Old clients may still connect to you at that point.. You are still using the same public / private key pair, just made a new 'lifetime version' of the certificate for it. (That is what most public servers do..)
Using two sets of active SSL certificates for different keys on the server side is not really viable and only possible if you have good control over the handshake process on the client side and your server application supports it. The issue is that during an SSL negotiation, the server has to send its certificate first and the only indication it might get from the client is a ServerName extension during the ClientHello. (Assuming the client actually sends one). Otherwise the server is 'at a loss' on what the other side will or will not support. (There are some other extensions that might help for in indicating supported CA certificates, but your clients should support those).
The first is the most practical for the clients that do support it. Just renew their certificates (and perhaps keys) and push them. And you are done with those.
For the others, updating the client software and making sure they generate a new key and request a new certificate from the server when they need it (or in advance) might be the best solution.
Related
I am working on an embedded device (Arduino) that connects securely to specific domains. To achieve this, certificates (domains), e.g. arduino.cc:443, are uploaded to the device via an updater tool (WiFiNINA certificates updater in Arduino IDE).
I'm wondering whether these certificates will need to be updated in the future? The plan is to ship the devices to customers, so I'm hoping this will not be necessary.
As long as the server side domain/website/api keeps its certificates updated, I assume it will not be necessary to update certificates on the clients?
Thanks.
All certificates have a limited life time and this is true for client certificates too. Depending on the life time of the certificate and the expected life time of the device this means that the certificate needs to be renewed - assuming that normal certificate validation is done. Of course one might decide to use a different certificate validation on the server, like pinning to a specific public key and ignoring any expiration.
We have a website with SSL configured. 2 days back SSL certificate was expired so I purchased a new instead of renewing. I have configured the new one. Now some of users are still getting SSL certificate expired issue although the new one is configured.
I want to force the browser to recheck the new SSL certificate using some server side configuration since we can not go and update each user browser certificate manually. It have to be done using some server side configuration. We are using Nginx.
This is really critical to us.
Please help in this regard.
Thanks!
The certificate is validated by the client only when the server sends one. The server sends one with each full TLS handshake. The browser does not somehow cache an old certificate and ignore the one sent by the server when validating.
It is more likely that you've not fully rolled out the new certificate on the server side. For example if you have multiple servers make sure that all have the new certificate. If your server provides access for IPv4 and IPv6 make sure that in both cases the proper certificate is served. If you provide service on multiple ports make sure that they all use the new certificate.
It's also possible your affected users are behind a proxy that caches certificates. For example if they're behind a Smoothwall proxy that generates its own certificates after inspecting HTTPS traffic and caches them.
Either way, if you've updated the certificates on your server and restarted the necessary services, it's probably nothing you have control over and will most likely resolve itself in time.
Context:
I have an application that is deployed to each client as a Virtual Machine. The latter is installed by the clients wherever they want (I don't necessarily know the final domain). The application comprises an JBoss Web Server that provides access to a configuration page, protected by SSL. Right now the server is using a self signed Certificate. However, I want the browsers to stop showing the warning messages associated to self signed certs. Moreover, I provide a free version of the application that has basic functionality.
Question:
For cases where the client is using a free version (and me wanting to reduce costs), what is the best approach when using a SSL cert, and not knowing the final domain (most of the time)?
It is acceptable to use a self-signing cert? If so, a different one
per client install?
Is it best to issue a new cert (maybe a free one) for each
deployment?
Is is acceptable to use the same cert, signed by a proper CA, on all
of the deployment VMs?
A completely different approach?
Thanks guys!
It is acceptable to use a self-signing cert? If so, a different one per client install?
Ask your clients. Will they put up with a browser warning? or not?
Is it best to issue a new cert (maybe a free one) for each deployment?
It is best for the client to acquire his own SSL certificate. You can't do that for him. Nobody can.
Is is acceptable to use the same cert, signed by a proper CA, on all of the deployment VMs?
No, it entirely defeats the purpose. The certificate and the private key it wraps are supposed to uniquely identify the holder.
A completely different approach?
Handball the whole megillah to the clients. Self-identification is their problem, not yours.
I have a web service which is secured through HTTPS. I also have client software which talks to this web service, using libcurl (which may be linked to OpenSSL, or linked to GnuTLS; I don't know which one, it depends on how the user installed libcurl). Because the web service is only ever accessed through the client software and never through the browser, the web service utilizes a self-signed certificate. The client software, in turn, has a copy of this self-signed certificate and explicitly checks the connection against that certificate.
Because of Heartbleed, I want to change the private key and certificate. However I want my users to experience as little service disruption as possible.
For this reason, I cannot change the key/certificate on a fixed date and time. If I do this then all users must upgrade their client software at that exact date and time. Otherwise, the upgraded client software won't work before the server change, while old versions of the client software won't work after the server change.
Ideally, I want to tell my users that I'm going to change the certificate in 1 month, and that they have 1 month time to upgrade the client software. The client software should be compatible with both the old and the new certificate. Then, after 1 month, I can issue another client software update which removes support for the old certificate.
So now we've come to my question: can I append the old certificate and the new certificate into a single .crt file? Will this cause libcurl to accept both certificates? If not, what should I do instead? Does the behavior depend on the SSL library or version?
Tests on OS X seem to indicate that appending both certificates into a single file works, but I don't know whether this is OS X-specific behavior, or whether it works everywhere. My client software has to support a wide range of Unix systems, including Linux (multiple distros) and FreeBSD.
Short answer: You can't.
Long answer:
Yes you can put multiple certificates in a single .crt file, regardless of platforms.
However HTTPS can only serve one certificate, instead of a crt file. So it's not the file that is limiting you, it's the protocol.
You could have a look at SNI https://en.wikipedia.org/wiki/Server_Name_Indication
to be able to serve another certificate based on the SNI information sent by the client at the beginning of the SSL Handshake
Alternatively, you could use a separate TCP port (or IP, or both) that will serve the new certificate.
But you say
The client software, in turn, has a copy of this self-signed certificate and explicitly checks the connection against that certificate.
This then requires you to release a version of your software for your clients to run, to at least have the copy of the new certificate you are going to use.
I guess you should better use a certificate signed by well-known CA, to decouple your server certificate from its validation chain, but that indeed means paying.
Yes a cert file should be able to hold multiple certificates. I would expect this to be broadly supported.
What's necessary to migrate valid SSL certificate from one server and service provider to another?
In some cases it may be simply a matter of copying the keys to and changing apache configuration on the new server.
For example:
http://www.digicert.com/ssl-support/apache-ssl-export.htm
Some certificate authorities may tie an SSL certificate to a specific server.
Essentially, you export SSL certificates from the server that they are currently installed on, move SSL certificates to the new server, and then import SSL certificates on the new server. But this only really only applies if you are sticking with the same certificate authority ("provider")... which it sounds by your question that you are not.
Keep in mind that even if you stick with the same provider, many require that you purchase a "server license" for each server that you install an SSL certificate to, even if it uses the same private key. And speaking of private keys, it is slightly less secure to copy the SSL certificate and use the same private key on a different server. If an attacker breaks into one server and gets the private key, he will be able to listen in on the connections that other servers are making.
So my advice to you since you want to switch providers is just purchase a new one all together with the new provider once you move to the new server... But maybe I'm misunderstanding your question.
First determine if the device installed with the certs are storing the private key in hardware/software. In most today's servers, they are in software *.key files (e.g. web server SSL).
To be found near the key files are the certificate and perhaps even CSR. Moving these files to another server is generally allowed (Considering the destination server will have the same hostname) and hence keeping the same CA. Most CAs have no concern to customers who does that.
But if you are just looking to switch the service provider from one to another, simply ask current CA to 'revoke' the cert. Then start with the new Cert buying process with the new CA.