Using letsencrypt to sign SSL certificates for local servers - ssl

Can I use a certificate from letsencrypt to sign local certificates?
I'm annoyed when accessing routers and APs at 192.168.x.x to get security warnings.
I could create my own root cert, and import it into all my browsers etc, and create certs for all the local servers.
But I'd rather have the chain device -> www.example.com -> letsencrypt -> root
Then also guests could use my local servers/services without this security error.

No, you can not because the certificate issued to you by letsencrypt will not have the keyusage certificate signing enabled. Without this attribute in the issuer, any browser or SSL client musth reject the certificate.
If this were possible, anyone could issue valid certificates for any server simply by having a valid certificate from a trusted CA
If you want to issue certificates for your local servers you will need to create your own CA and include the root certificate in the truststore of each client

Yes, you can... but not like that
Yes, you can get certificates for servers on a private network. The domain must be a real domain with public txt records, but the A, AAAA, and CNAME records can be private/non-routable (or in a private zone).
No, the way to do that isn't by using Let's Encrypt certificates to sign local certificates.
You can accomplish exactly what you want to accomplish using the DNS-01 challenge (setting txt records for your domain).
Who is your domain / dns provider?
Immediate, but Temporary Solution
If you want to test it out real quick, try https://greenlock.domains and choose DNS instead of HTTP for the "how do you want to do this" step.
Automatable Integration
If you want a configurable, automatable, deployable solution try greenlock.js (there are node plugins for Cloudflare, Route 53, Digital Ocean, and a few other DNS providers).
Both use Let's Encrypt under the hood. Certbot can also be used for either case and can use python plugins.
Possibly related...
P.S. You might also be interested in a service like Telebit, localtunnel, or ngrok.

Related

All domain names showing up in a single ssl certificate

I just installed a Cloudflare Origin CA ssl certificate on my server. Because I have many domains on this server, I configured the certificate to protect them all, so I can use only one certificate for all my domains (domain1.com, domain2.com, etc...).
I went to check my ssl was working properly with the service whynopadlock.com, and I realized this service can list ALL of my domain names on the server by just accessing domain1.com? Are all the domains in a certificate meant to be public, is this normal behavior and can I avoid it?
I also noticed whynopadlock.com lists some domains in the certificate that are not mine. Does it mean Cloudflare is using the same certificate for many different users?
Are all the domains in a certificate meant to be public, is this normal behavior and can I avoid it?
All certificate subject alternate names are part of the certificate and are sent to every client that tries to connect securely.
There is no way to avoid it unless you want to use separate certificates for each domain.
I also noticed whynopadlock.com lists some domains in the certificate that are not mine.
Cloudflare states that this is normal:
Are Cloudflare SSL certificates shared?
Universal SSL certificates are shared across multiple domains for
multiple customers. If certificate sharing is a concern, Cloudflare
recommends a Dedicated or Custom SSL certificate.
Note that Cloudflare (as of Feb 2019) does provide dedicated certificates if you do not want to use a shared certificate.

simple Akka ssl encryption

There are several questions on stackoverflow regarding Akka, SSL and certificate management to enable secure (encrypted) peer to peer communication between Akka actors.
The Akka documentation on remoting (http://doc.akka.io/docs/akka/current/scala/remoting.html)
points readers to this resource as an example of how to Generate X.509 Certificates.
http://typesafehub.github.io/ssl-config/CertificateGeneration.html#generating-a-server-ca
Since the actors are running on internal servers, the Generation of a server CA for example.com (or really any DNS name) seems unrelated.
Most servers (for example EC2 instances running on Amazon Web Services) will be run in a VPC and the initial Akka remotes will be private IP addresses like
remote = "akka.tcp://sampleActorSystem#172.16.0.10:2553"
My understanding, is that it should be possible to create a self signed certificate and generate a trust store that all peers share.
As more Akka nodes are brought online, they should (I assume) be able to use the same self signed certificate and trust store used by all other peers. I also assume, there is no need to trust all peers with an ever growing list of certificates, even if you don't have a CA, since the trust store would validate that certificate, and avoid man in the middle attacks.
The ideal solution, and hope - is that it possible to generate a single self signed certificate, without the CA steps, a single trust store file, and share it among any combination of Akka remotes / (both the client calling the remote and the remote, i.e. all peers)
There must be a simple to follow process to generate certificates for simple internal encryption and client authentication (just trust all peers the same)
Question: can these all be the same file on every peer, which will ensure they are talking to trusted clients, and enable encryption?
key-store = "/example/path/to/mykeystore.jks"
trust-store = "/example/path/to/mytruststore.jks"
Question: Are X.509 instructions linked above overkill - Is there a simple self signed / trust store approach without the CA steps? Specifically for internal IP addresses only (no DNS) and without an ever increasing web of IP addresses in a cert, since servers could autoscale up and down.
First, I have to admit that I do not know Akka, but I can give you the guidelines of identification with X509 certificates in the SSL protocol.
akka server configuration require a SSL certificate bound to a hostname
You will need a server with a DNS hostname assigned, for hostname verification. In this example, we assume the hostname is example.com.
A SSL certificate can be bound to a DNS name or an IP (not usual). In order for the client verification to be correct, it must correspond to the IP / hostname of the server
AKKA requires a certificate for each server, issued by a common CA
CA
- server1: server1.yourdomain.com (or IP1)
- server2: server2.yourdomain.com (or IP2)
To simplify server deployment, you can use a wildcard *.yourdomain.com
CA
- server1: *.yourdomain.com
- server2: *.yourdomain.com
On the client side you need to configure a truststore including the public key of the CA certificate in the JKS. The client will trust in any certificate issued by this CA.
In the schema you have described I think you do not need the keystore. It is needed when you also want to identify the client with a certificate. The SSL encrypted channel will be stablished in both cases.
If you do not have a domain name like yourdomain.com and you want to use internal IP, I suggest to issue a certificate for each server and bound it to the IP address.
Depending on how akka is verifying the server certificate, it would be possible to use a unique self-signed certificate for all servers. Akka probably relies trust configuration to JVM defaults. If you include a self-signed certificate in the truststore (not the CA), the ssl socket factory will trust connections presenting this certificate, even if it is expired or if the hostname of the server and the certificate will not match. I do not recomend it

Can I regenerate SSL certificate with different common name?

I am going to use an SSL certificate on my chat application based on XMPP(ejabberd) which is hosted on an IP.
So, I will be using the IP as the common name when I am generating my SSL certificate. But the server that has everything hosted on it, refers to the IP using a hostname as abcd.yourserver.net.
Therefore, I am confused as to if I have to use the IP or this weird hostname while generating my SSL certificate and if in future I decide to use a domain name instead of the IP for my application, will I have to buy a new SSl certificate or can I regenerate the old one. Also, can I change the type like wilcard or single certificate?
P.S. I have never bought an SSL certificate, so forgive me if the question is newbish.
When generating an SSL certificate for an XMPP server, you have to use the domain name of your XMPP service.

SSL: where is the certificate hosted? when does the verification occurs?

I am quite confused here:
I use DNSMadeeasy to manage my DNS. I have two apps.
One is Heroku hosted, and has https on https://example.com - Heroku has many great tutorials to setup the certificate, it hasn't been a problem.
The other one is a wordpress, hosted in 1and1 (though it shouldn't matter here), and is reachable at http://subdomain.example.com and we want it to be available at https://subdomain.example.com
1and1 does sell SSL certificate, but their automated setup works only when one uses their services for DNS also, as they say. Their support says it should be DNSMadeEasy which should be hosting our SSL certificate. I have the feeling it is not true, because for https://example.com, DNSMadeEasy was never involved.
Questions:
When does certificate querying occurs? Before, After, or in parallel of DNS resolution?
Who is hosting a certificate? The DNS provider? The server (accessible like a sitemap.xml at the root for instance)? A third party?
To enlarge the case, in general if I have a personal server with a fix IP, how can I communicate through https with a valid certificate?
In my case, how can I get my way out of it to make https://subdomain.example.com work?
You are right for not believing the 1and1 suggestion.
To answer your questions:
When does certificate querying occurs? Before, After, or in parallel
of DNS resolution?
A client resolves domain name to an IP address first. So DNS resolution happens first.
Who is hosting a certificate?
The server (in simplistic terms) hosts the certificate.
When a client wants to connect to your site (via HTTPS) it will first establish a secure connection with that IP address on port 443 (this is why usually (without SNI) you can only have one SSL certificate per IP address). As part of this process (which is called handshake) a client can also specify a server name (so-called server name extension) - this is a domain name of your site. This is useful if you have an SSL certificate that is valid for multiple domains.
A good/detailed explanation how it works can be found here
http://www.moserware.com/2009/06/first-few-milliseconds-of-https.html
if I have a personal server with a fix IP, how can I communicate
through https with a valid certificate?
Your server will need to be able to respond on port 443 and have/host an SSL certificate for a domain that resolves to that IP address.
In my case, how can I get my way out of it to make
https://subdomain.example.com work?
You need to purchase a certificate for subdomain.example.com and install it on the wordpress server.
Usually in hosted solution like yours you have 2 options:
Buy the SSL certificate via the provider (1and1 in your case) - a simpler option, they will configure everything for you.
Buy the SSL certificate yourself. Here you will most likely need to login to your 1and1/Wordpress management interface and generate a CSR (essentially a certificate request). Then you purchase the SSL certificate using this CSR and then you can install it via the same management interface.
The process will look similar to this:
http://wpengine.com/support/add-ssl-site/

Is it possible to automatically select correct client side certificate?

I have configured an Apache httpd website with SSL client side certificates so that only users who have installed the correct certificate in their web browsers can access the website.
If there is only one client side certificate installed the web browser will automatically select it (it is not the default, but it can be configured somewhere in the settings dialog). But if a user has more than one certificate installed, the web browser presents a list of certificates and the user has to pick the right one to continue.
The question is: Is there a way to configure httpd to send a hint so that the web browser can automatically select the required certificate?
The SSL (TLS) protocol only allows the server to specify two constraints on the client certificate:
The type of certificate (RSA, DSA, etc.)
The trusted certificate authorities (CAs) that signed the client certificate
You can use "openssl s_client" to see which CAs your Apache server trusts for client certs. I do not know how to configure Apache to change that list (sorry), but I bet there is a way. So if you can limit the list to (say) your own organization's CA alone, then you will have done all you can to allow a Web browser to select the client cert automatically.
As Eugene said, whether the browser actually does so is up to the particular browser.
I'd say that as selection of the certificate is a client-side task, there's no definite way to force the client use this or that certificate from the server side.
In addition to what #Nemo and #Eugene said, by default, Apache Httpd will send the list of CAs it gets from its SSLCACertificateFile or SSLCACertificatePath configuration directives.
However, you can force it to send a different list in certificate_authorities using the SSLCADNRequestFile or SSLCADNRequestPath directives and pointing them to another set of certificates. Only the Subject DN of these certificates is used (and send in the list). If you want to force certain names, you can even self-sign these certificates with whichever name you want. I've tried this (in conjunction with SSLVerifyClient optional_no_ca, and you can get clients to send certificates for CA certificates that the server doesn't actually have. (This isn't necessarily useful, but it works.)