I have a Code Signing Certificate but it looks like I can't use it for Microsoft ClickOnce. It looks like ClickOnce requires the certificate to be an Authenticode Certificate. How can I tell that a (code signing) certificate is indeed an Authenticode Certificate?
The only EKU that ClickOnce checks for (as far as I can tell) is id-kp-codeSign (1.3.6.1.5.5.7.3.3). You also need DigitalSignature as a (non-extended) Key Usage. And, of course, a way of getting at the private key.
Related
In order to use an EV certificate for CI, GitHub actions offers this action: https://github.com/marketplace/actions/authenticode-cloud-signer
This takes advantage of Googles Key Management System (KMS) to deliver hardware key security with HSM.
The options are pretty self-explanatory except for the certificate option which requires the base64 encoded certificate chain in PEM format.
How does one export the certificate as .pem? I use SafeNet to manage the eToken if that helps.
We are using IdentityServer4 and our version loads the signing key from a PFX file in file system or from the windows certificate store. Using the certificate works. The question is - which certificate issuer should be used in production?
Is a certificate from a public CA recommended? Or is it enough to have a self-signed certificate (without a CA at all) such as it can be created with IIS Manager?
In our tests we have found that the client could still validate the signature in the access token, even if the signing certificate would not have a valid CA chain on the client.
In the docs, it says that you can also use raw key material instead of a certificate:
http://docs.identityserver.io/en/latest/topics/crypto.html#token-signing-and-validation
In this scenario there would be no CA chain whatsoever.
That leads me to the assumption, that when the client loads the public signing key (via the HTTP(s) endpoint), the CA chain information might not be passed anyways. Is that right? Through the loading mechanism via HTTPs you also have a combined security mechanism.
So my conclusion is that for the signing credential a self-signed cert is just as safe as one from VeriSign. Can this be confirmed?
There is no certificate involved in signing and verifying the tokens. Only a private and public key (RSA or ECDSA key).
However a certificate can be useful to "import/transport" the keys into .NET. So, because of that we don't care about who issued the certificate.
When importing the key, one approach is to bundle the certificate that holds the public key + the private key and store it in a PKCE#12 file (.pfx/.p12 extension). Then load that file into .NET. Before .NET 5 working with keys was a bit hard.
The more important thing is that you can manage and deploy the private key in a secure way and that it is persisted over time.
Optionally, you can add support for key-rotation.
I am developing a desktop application. I can code sign it with .pfx file. I will get that from CA. But what if I want to install it in a different system. Will it reflect there as well? Because I can't share my .pfx file with everyone.
You should not share the *pfx as it contains the private key.
The trust to the signature comes from the trust chain - so when the issuing CA and all intermediate CAs up to the root CA are in the trust store (Windows Trust Store, MAC Key Chain or cacerts.pem for OpenSSL/Java) the signature is trusted as long as
the certificate is not revoked
the signature certificate is not expired or the signature contains a counter signature (RFC3161 timestamp).
How can I export the Token Signing Certificate that is created when ADFS 3.0 is installed? When I open up the certificate MMC, I am able to see the certificate however the message 'You have a private key that corresponds to this certificate' is missing and I am unable to export the private key. I read in the article ADFS deep dive: Certificate Planning that I can find it in Active Directory in the following container:
CN=ADFS,CN=Microsoft,CN=Program Data,DC=domain,DC=com
However, although I can get to that container, all I see is a GUID inside and do not know how to export the private key out of Active Directory.
How can I get the private key?
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In case anyone comes to this later, the certs are actually in the personal cert store of the ADFS service account but they are NOT exportable. You almost certainly want the SSL cert private key NOT the token signing cert private key. The documentation
I was following to set up ADFS for SharePoint was a little confusing. The private key had to exported for the SSL cert, however the thumbprint of the token signing cert had to be placed in the web config. I was incorrectly trying to export the private key of the token signing cert.
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You mean the self-signed ones you get with automatic rollover?
If so, where do you see these with mmc?
They are stored in a combination of an AD container and the ADFS DB.
So you can't export in the normal manner.
For a very good reason - security. If you have the private key you can send / hack anything and it will be accepted as coming from ADFS.
The public key is available in the metadata.
If you have to do this, turn off automatic rollover and use your own certificates.
I'm using the SignedXml.CheckSignature(X509Certificate2, boolean) method. I would like to know what checks are performed when deciding the validity of the certificate. I have verified that the Current User/Not Trusted list is checked. The documentation says it will use the "address book" store, searching by subject key identifier, to build the certificate chain. I imagine this means the Local Machine and Current User certificate stores?
Am I right to think that certificate revocation and signature timestamp are not checked? To do an OCSP check for certificate revocation, am I obliged to use Bouncy Castle?
In the remarks in the msdn article you link to one finds:
In version 1.1 of the .NET Framework, the X.509 certificate is not verified.
In version 2.0 and later, the X.509 certificate is verified.
In version 2.0 and later of the .NET Framework, the CheckSignature method will search the "AddressBook" store for certificates suitable for the verification. For example, if the certificate is referenced by a Subject Key Identifier (SKI), the CheckSignature method will select certificates with this SKI and try them one after another until it can verify the certificate.
Thus, first of all the behavior of that method has changed in different .NET framework versions. So for reproducible results, you had better not count on that method even check the certificate at all.
Furthermore, the formulation try them one after another until it can verify the certificate sounds like there just might be the mathematical test whether or not the certificate is signed by its alleged issuer.
https://referencesource.microsoft.com/#System.Security/system/security/cryptography/xml/signedxml.cs,b9518cc2212419a2
It checks
The certificate has no Key Usage extension, or the Key Usage extension has either Digital Signature or Non Repudiation usages enabled
The certificate chains up to a trusted root authority
The certificate has not been revoked
The certificate was not expired when you called this method
It doesn't know when the document was signed, so it doesn't answer that question.
That none of the certificates in the chain are explicitly prohibited by the user or system configuration.