I did a rekey on my app service certificate, however the expiration time of my certificate has not changed.
Re-keying an SSL certificate refers to creating a new private key for your certificate, which is used in the process of encrypting and decrypting data sent from and to your website.
Performing a re-key operation only gets a new key and has no effect on the expiration date. If you want to extend the expiration of the certificate, you need to renew it. You may also set the autorenew to true and the system will automatically renew the certificate.
PFB document that explains Rekey and sync certificate:
https://learn.microsoft.com/en-us/azure/app-service/web-sites-purchase-ssl-web-site#rekey-and-sync-certificate
Related
I have generated a self-signed RSA certificate in Azure KeyVault. When creating a new version of the certificate manually or automatically via the auto-renew feature, I noticed that the public/private key pair is not rotated, only the certificate part is renewed, and signed with the original key.
How can I rotate the key pair as well, which I want to do periodically for security reasons, in case the private key gets leaked through some means?
When a Key Vault certificate is created, an addressable key and secret are also created with the same name. The Key Vault key allows key operations and the Key Vault secret allows retrieval of the certificate value as a secret.
From RFC.
Certificate renewal means the issuance of a new certificate to the subscriber without changing the subscriber or other participant's public key or any other information in the certificate:
Circumstances under which certificate renewal takes place, such as where the certificate life has expired, but the policy permits the same key pair to be reused;
Certificate Re-key
Certificate Re-key means generating a new key pair and applying for the issuance of a new certificate that certifies the new public key:
Circumstances under which certificate re-key can or must take place, such as after a certificate is revoked for reasons of key compromise or after a certificate has expired and the usage period of the key pair has also expired;
Azure KeyVault self-signed certificate certificate renewal do not rotate public/private key pair by default.
You can rotate it by updating the policy for your certificate in the Azure KeyVault, where you can set ReuseKeyOnRenewal to false.
https://learn.microsoft.com/en-us/azure/key-vault/certificates/about-certificates
I have an SSL certificate that I am using to secure port 443 (HTTPS) on my nginx server running on Ubuntu for about 10 months now.
When I bought the cert, I got it for one year, so I have about 2 more months with this certificate.
My question is: "When I renew this cert, Will I just need to pay for renewal? or will I have to re-issue the cert with a new CSR, and have a potential downtime while installing?
I need to plan for any downtime from now.
Thanks in advance for your answers.
It's not possible to extend the expiration of an existing certificate once issued. The only way is to issue a new certificate.
Most certificate authorities offers a "renewal" concept, which provides some advantages compared to a new purchase. For example, you can renew in advance to the certificate expiration, and they will issue the new certificate from the expiration of the previous one, and not from the day the new one is issued.
The re-issue or re-key is a different thing. It generally means re-keying an existing certificate order with a different private key and/or CSR. It generally doesn't change the expiration of the certificate, hence it's not a renewal. Both renews and rekeys result in a new certificate (again, it's not possible to change an existing certificate once issued), but the rekey only alters the certificate information and not the expiration.
A renewal can be issued with the same original CSR and key, or with a completely new one. It's up to you.
As in all cases a new certificate is issued, you will have to replace the existing one. Replacing a certificate is generally a no-downtime task. You simply upload the new one, change the server settings and reload them (or restart the server).
Most webservers including Nginx supports hot reloads, therefore you don't need to restart the server and wait for it to reboot.
If planned correctly, the renewal will be a no downtime task.
To get the new one you might or might not need to submit a new CSR, depending on the CA. But in any case you get a new certificate file and need to replace the existing certificate on your server with a new one. See also
https://www.digicert.com/ssl-certificate-renewal.htm
Renewal of SSL certificate keeps security on your website alive along with your verified identity. The lapse in renewal can cause a warning on your website and warns your customers to move away from your site.
It depends on the SSL provider that you should continue with old CSR or generate new CSR, but it is recommended to create a new one to get rid of misconfiguration. However, it is a myth that your server will face downtime in the renewal of SSL certificate.
Certificate renewal and re-issuance both are different terms. Certificate renewal happens after the expiry of a certificate, while certificate re-issuance in the case of lost of a private key, want to change the domain/organization name or add new SAN names.
Most certificate providers are sending renewal reminder email frequently before certificate expiry. So, It is advisable to renew your certificate earlier, you can take advantage of getting additional validity period from early renewals.
This article may help you to understand the certificate renewal process. https://www.ssl2buy.com/wiki/how-to-renew-ssl-certificate/
Shortly to answer, no renewing SSL Certificate does not require re-issuing the cert, simply because reissue and renewal are 2 different actions with SSL certificate.
As you explained your situation, you are left with 2 months with your existing certificate and after that it will expire, so a Renewal is required. A Reissue (Revoke & Replace) is quite different, in that you cancel your current, valid SSL/TLS Certificate due to any of the reason and request for a new one.
Reissue:
Reissue of Certificates is the process where certificate has to be regenerated with Certificate Authority if needed. For example, if you have lost your Private Key. For that CA views the details of your certificate from list of certificates they have and then reissue the Certificate.
Furthermore, the process is quite same like in similar way activation will take place, like pasting of CSR for same domain name, selecting & approving of email. Reissuing of certificate change its Certificate ID & a new certificate record is also added into the account.
Renewal:
On the other hand renewal of certificate may seems pretty much same as purchasing new certificate, but it’s different. Renewal functionality is fully integrated within the module. If the settings of "Payment Type" is set to "Recurring" while creating a product, invoices for renewals will be generated automatically. Once paid, renewal of SSL certificates will be created automatically as well. Though one thing to note is that, after the renewal of SSL still activation is required through CSR.
Now one important thing is that, if you renew it before actual expiry date, like in your situation before 2 months, your new certificate will have expiration date one (or several, if you choose to be more than one year duration) year from the expiration date of the initial SSL certificate, so you will not lose any time on it.
I have some secrets that I would like to keep in Azure Key Vault. I know I can use a client id and certificate to authenticate with Key Vault instead of using a client and and secret following these steps:
Get or Create a Certificate
Associate the Certificate with an Azure AD application
Add code to your application to use the Certificate
Most examples use either makecert or New-SelfSignedCertificate to create the certificate. Is a self signed certificate problematic in this case for a production application? This is only for an application to authenticate with Azure Key Vault and it's not something a client will ever see in their browser.
If a self signed cert is still frowned upon in this case then is purchasing a cert from a trusted authority the same process as purchasing an SSL/TLS certificate? Is it even the same type of certificate?
There is (with some caveats) nothing inherently wrong with using a self-signed certificate. There is no difference from a pure crypto perspective between a purchased and a self-signed certificate. The sole difference is that a purchased certificate has been signed by one or more certificate authorities (CAs) who distribute their public keys with most browsers/operating systems/etc. This means that a user can have a much higher confidence that a purchased certificate is legitimate, while they must take a leap of faith to accept a self-signed certificate.
In your case, however, you seem to be able to control the client application, and actual users should never see this certificate. Therefore, you can use a self-signed certificate without worry, so long as you take precautions to prevent man-in-the-middle attacks (i.e. someone generating their own self-signed certificate and pretending to be you.). One of the most effective ways to do this is via certificate pinning. In essence, you ship the public key for your certificate with you client application, and your client application will only accept certificates that provide that public key. This makes it much more difficult for a malicious actor (who has not stolen your certificate) to preform a man-in-the-middle attack.
TL;DR: So long as you take steps to prevent man-in-the-middle attacks, and you keep your certificate secure, there is nothing wrong with using a self-signed and self-generated certificate to secure non-user-facing connections.
why do we need to do server certificate validation at the of SSL renegotiation? thought process behind of my question is that when ssl tunnel is already created and all the handshake would happen through existing tunnel and moreover we already trusted the server then why do need to do the certificate validation again?
This is because security certificate status can be changed. For example, the certificate is expired and new revocation information is available and SSL certificate is no longer trusted. And this is one of the reasons why renegotiation is ever used (besides key management questions).
Update:
Server certificate is used only during SSL tunnel negotiation. Once it is done, a symmetric session key is used to protect entire session. Server certificate no longer play a role there until next negotiation.
I've read about SSL protocol and now, I know how it encrypts data. But there is something I couldn't understand. With SSL , you're sure you're sending data to and getting data from correct server. But how?
I mean if I create a fake certificate and send it for requests of special website, how do browsers ( or other programs) detect the fake certificate?
Edit: I didn't mean to create a self-signed certificate. I meant how can someone validate my certificate if I create a certificate that its issuer and subject ,etc are something to real certificate! (the only things that are not real is Public key & signature)
TL;DR summary:
Validity of a server certificate is established by:
Host name verification
Verifying the signatures of the entire certificate chain
Performing additional checks on meta data for each certificate
Checking the revocation status of each of the certificates involved
Checking whether the self-signed root certificate of the chain is among the certificates that one trusts by default
Explanation
Let's assume you want to connect to https://mail.google.com (you can try this out in your browser!).
The (real) server will respond with a certificate that is issued to mail.google.com, i.e. in the 'Subject' field of the certificate you will find the Common Name (CN) 'mail.google.com' - cf. RFC 5280 for details on the fields of certificates. The fact that the subject is linked to the site URL is very important for the security of the whole model, and it is actively checked by your TLS implementation ("host name verification"), because otherwise there would be room for Man-In-The-Middle attacks. I.e. somebody could acquire an otherwise valid certificate and impersonate mail.google.com without you taking any notice of it.
In addition to the host name verification, your TLS implementation will also check the "validity" of the certificate. The whole procedure is rather complex and does include checking the trustworthiness of the certificate, but additionally a lot of other things will be checked, more on that in a minute.
If you view Google Mail's certificate in your browser, you will notice that there are actually three certificates shown:
mail.google.com
Thawte SGC CA
Class 3 Public Primary Certification Authority (VeriSign)
The model is that there are a few (well, unfortunately not so few anymore) trusted root certificate authorities ("root CAs") that either you could choose on your own or (more likely) that come preconfigued with your software (e.g. browser) that are blindly trusted. These trusted authorities form the anchors of the entire trust model of "PKI" (Public Key Infrastructure). The basic idea is that the trusted entities may issue certificates to other authorities and grant them permission to again issue certificates (these authorities are called intermediate certificate authorities). The intermediate CAs may again recursively apply this procedure up to a certain point, the number of intermediate CAs between an actual end entity certificate and a root CA certificate is generally limited.
At one point, an intermediate CA will issue certificates to an "end entity" ("mail.google.com" in our example). Now the process of issuing a certificate actually means that the party requesting a certificate will create a public/private key pair first, and use them to authenticate a certificate request that is sent to the certificate authority. The issuing authority creates a certificate for the subordinate entity (either intermediate CA or end entity) by "signing" that certificate using its own private key using an asymmetric algorithm such as RSA and by additionally including the public key of the requesting party within the newly generated certificate. The root CA possesses a so called self-signed certificate, i.e. the root CA is the only authority that may sign their own certificate and include their own public key. The private key remains hidden at all times, of course.
The recursive nature of the certificate issuing process implies that for each end entity certificate there is a unique way of establishing a "chain" of certificates that leads up to a root certificate authority. Now when you are presented with an end entity certificate while trying to connect to a TLS-secured site, the following procedure will be applied recursively until you end up with a root CA certificate:
Find the certificate of the authority that issued the certificate to be validated (see RFC 5280 for details). If none is found: exit with error.
Take the public key of the issuing certificate and verify the signature of the to-be-validated certificate using this public key.
Check a lot of additional things such as whether the certificate has neither expired nor is it not valid yet, "policy constraints", "key usages", "extended key usages"... (again, the gory details are in the RFC).
Certificate revocation status (more on that later)
If all checks were positive, you will ultimately end up with a certificate being self-signed, i.e. where the subject is also the issuer (such as the VeriSign certificate in our example). Now the last thing you have to verify is whether this certificate is among those that you blindly trust: if it is, all is well and the connection will succeed, if it is not, the connection attempt will be rejected.
As if this were not complicated enough already, the checks described so far do not handle cases where once valid certificates suddenly become rogue, examples being cases where a certificate is stolen or private keys are compromised (think of Comodo and DigiNotar). In these cases, the normal procedure is to "revoke" those certificates gone bad, that is you want to mark them as being invalid starting from a distinct point in time (they will expire at some point anyway, but for the remainder of that period they shall already be marked as invalid). For these cases, CAs have the possibility to issue CRLs (a catalog of certificates declared as invalid) or OCSP responses (information for one or in rare cases a set of certificates) that provides clients with information whether a given certificate has been marked as invalid or not. The revocation status needs to be checked for all certificates in a chain, should one of them be marked as invalid then the end entity certificate cannot be trusted and the connection must be rejected as well.
SSL certificates are signed by a certificate authority (CA), which is someone the user already trusts (or more likely, the people who designed their operating system trusts).
The CA digitally signs the certificate using public key encryption. The basic explanation is that the CA has a "private key", and a "public key" that everyone knows. Via some math I don't understand, the CA can create a signature using its private key which can easily be verified with its public key (but the public key can't be used to create a new signature).
When you get an SSL certificate from a server, you get the server's public key, and a signature from a CA saying that it's valid (along with some other info). If you know and trust that CA, you can check the signature and determine if it's valid. You can also use a certificate revocation list to make sure it wasn't revoked.
So basically, you can recognize a bad SSL certificate because it isn't signed by a certificate authority that you trust.
Any fake certificate you create will be a self-signed certificate.
The browser will display big scary warnings when connecting to a site with a self-signed certificate which the user will promptly ignore.
In order to avoid warnings, you need a certificate signed by a certificate authority that the browser trusts, such as VeriSign.
These companies will hopefully make sure that you actually own the domain for the certificate they're signing.
Re: Edit: You can only create a non-self-signed certificate if you get it signed from a trusted CA.
They will refuse to sign a certificate for a different subject.
Process from my understanding:
server sends servers public key
server sends certificate (all information encrypted by trusted CA with their private key)
Your PC decrypts certificate with public key (built into OS from trusted CA)
Your PC hashes (with sha1 and sha256) the servers public key
Your PC compares the hashes of servers public key with certificate stored hash, if not same browser will block site
Your PC compares allowed domains from certificate and the domain, if not allowed, if not same browser will block site
Your PC compares valid date from certificate and your date, if not valid browser will block site.
To fake this you would either need to:
obtain a CA private key (extremely hard to get),
be a CA,
be part of the 5 eyes (Government intelligence agency alliance) and ask a CA for their private key
So if you see a padlock in the address bar you are almost always safe.
Certificates work because they follow a chain of trust. Certificates have a chain of one or more issuers that are trusted; this chain is the backbone of why it works at all. Browsers and nearly all SSL certificate libraries do this chain check, or at least provide the option to.
Self-signed certificates (or those issued by chains that end in a self-signed certificate) would fail this check.