I need to know how I can make sure certificate fields of my self-signed certificate, like subject common name and issuer common name, is encoded as PRINTABLE_STRING, IA5STRING or BMPSTRING, but not UTF-8 encoding.
I'm trying to create it using PowerShell cmdlet.
I'm trying to create a self-signed certificate that conforms to these rules.
These are the parameters I found that I think comply with those rules.
New-SelfSignedCertificate -DnsName 'wdac' -CertStoreLocation Cert:\CurrentUser\My\ -Type Codesigning -HashAlgorithm "SHA512" -KeyLength 4096 -KeyAlgorithm RSA
Related
Without using Windows Server or purchasing a certificate, how can I generate a self-signed certificate that meets these criteria?
All policies, including base and supplemental, must be signed
according to the PKCS 7 Standard.
Use RSA SHA-256 only. ECDSA isn't supported.
Don't use UTF-8 encoding for certificate fields, like 'subject common
name' and 'issuer common name'. These strings must be encoded as
PRINTABLE_STRING, IA5STRING or BMPSTRING.
Keys must be less than or equal to 4K key size
Certificate criteria screenshot
https://learn.microsoft.com/en-us/windows/security/threat-protection/windows-defender-application-control/use-signed-policies-to-protect-windows-defender-application-control-against-tampering
This is how far I got with Powershell:
New-SelfSignedCertificate -DnsName "WDACPolicy" -CertStoreLocation Cert:\CurrentUser\My\ -Type Codesigning -KeyLength 2048 -KeyAlgorithm RSA
but it's not right yet, I don't know about other rules mentioned there.
I make my own certificate with signTool like
powershell.exe New-SelfSignedCertificate -DnsName "www.mydns.me" -Type CodeSigning -NotBefore 27.10.2021 -NotAfter 27.10.2024 -CertStoreLocation "cert:\CurrentUser\My"
The certificate is availabe in certificate manager
I signed my file with
signtool sign /tr http://timestamp.digicert.com /td sha256 /fd sha256 /a myfile.exe
I want to show certificates on the file with
signtool verify /pa myfile.exe
but it gave the source is not trusted
SignTool Error: A certificate chain processed, but terminated in a root
certificate which is not trusted by the trust provider.
Why is certificate not trusted when the option is /pa and is available in my certificate center.
The self signed certificate is self-signed and stored in your current user certificate Personal store.
This is not because you have the certificate that you trust it or the computer trust it.
You must import a copy of this certificate in the Trusted Root Certification Authorities. You can import it in the user store or computer store (any user on the local machine would trust your self signed certificate).
Use by example Import-Certificate -CertStoreLocation Cert:\CurrentUser\Root -FilePath C:\cert.cer. Only the public key must be imported in the Trusted Root Certification Authorities store and not the private key.
I don't know for the /pa option. Try without any option.
How To Generate A Self Signed Certificate Signed By An Root Certificate using New-SelfSignedCertificate, I Have A Root Certificate I Just Want to Know How To Use -Signer.
You already figured out that you need to use the -Signer parameter. Just ensure that you have the private key for the certificate you want to use to sign the new certificate. So basically you can only use certificates from the Personal store ("My" in PowerShell).
Example:
# find a suitable certificate to use as root
ls Cert:\CurrentUser\My\
$root = ls Cert:\CurrentUser\My\c123a6f16a5f165161a1... # use the thumbprint of one of your certificates
# create a certificate which is signed with your chosen root certificate
New-SelfSignedCertificate -DnsName test.local -Signer $root -CertStoreLocation Cert:\CurrentUser\My\
I have a question, basically I have a file one txt and another one xml, I would like to sign those files with self signed certificate using Powershell.
Is there a way to do it?
My steps would be like that?
First create a self signed certificate with powershell
Then use that certificate in Powershell to sign the documents
Is that correct?
Any idea how to do that?
After the document is signed do I have to provide to another party this self sigend certificate to be able to open the files right? Or how will it work?
Accidentally, all my scripts are signed with an issued certificate, and it's my cmdlets to sign:
$cert = Get-ChildItem Cert:\CurrentUser\My -CodeSigningCert
Set-AuthenticodeSignature _path_to_my_script_ $cert -HashAlgorithm `
sha256 -TimestampServer "http://timestamp.digicert.com"
As to certificate, an issued one is recommended, rather than a self-signed one, it's not very expensive.
If you want to use a self-signed certificate, I think this cmdlet helps you:
New-SelfSignedCertificate -FriendlyName "My Cert" -KeyUsage DigitalSignature -KeyUsageProperty Sign -KeyLength 2018 -KeyAlgorithm sha256 -Type CodeSigningCert -Subject "CN=System Error,e=mymail#mail.com"
I never created self-signed certificate on a personal computer, so this cmdlet is not verified. :(
If you have further questions, please let me know. :)
PowerShell 4.0
makecert tool has the -eku option for describing the enhanced key usage object identifiers (OIDs) into the certificate. It allows to make the certificates for code signing and for other purposes. But it is not a cmdlet.
New PowerShell versions have the New-SelfSignedCertificate cmdlet for local testing of the scripts. But it creates the certificate that can't be used for code signing:
New-SelfSignedCertificate -DnsName www.SomeSite.com -CertStoreLocation Cert:\CurrentUser\My
I don't see an option which is similar of -eku.
How can I set the destination of my new Self-Signed Certificate (created through New-SelfSignedCertificate cmdlet) for possibility of its use for code signing? Or is it possible to do the same via other cmdlet?
The version of New-SelfSignedCertificate on PS 4 is rather basic.
However Powershell v5 has the parameters that you would require to create specific keys.
Specifically a Keyusage parameter that takes
-- CertSign
-- CRLSign
-- DataEncipherment
-- DecipherOnly
-- DigitalSiganture
-- EncipherOnly
-- KeyAgreement
-- KeyEncipherment
-- None (default)
-- NonRepudiation
and a KeyUsageProperty taking
-- All
-- Decrypt
-- KeyAgreement
-- None (default)
-- Sign
Are you specifically tied to v4? If you can upgrade to v5 you should be able to achieve what you need.
Reviving this question as I was also looking for an answer to set Enhanced Key Usage (EKU) field for code signing using PowerShell New-SelfSignedCertificate command.
It can be done using the -TextExtension parameter to set EKU value. As an example, the following PowerShell (tested on PowerShell 5.1) script allows to create a 3-years self signed code signing certificate with extended key usage (and export it from the current user's certificates store to pfx file format):
# Enhanced Key Usage
$EKU = "2.5.29.37"
$EKU_CODE_SIGNING = "1.3.6.1.5.5.7.3.3"
$certificate = New-SelfSignedCertificate -Subject "CN=Testing Code Signing,E=info#mycompany.com,O=My Company" `
-FriendlyName "My Code Signing Certificate" `
-NotAfter (Get-Date).AddYears(3) `
-CertStoreLocation Cert:\CurrentUser\My `
-TextExtension #("$EKU={text}$EKU_CODE_SIGNING")
$password = ConvertTo-SecureString -String "mypassword" -Force -AsPlainText
Export-PfxCertificate -Cert "Cert:\CurrentUser\My\$($certificate.Thumbprint)" -FilePath "codesigning.pfx" -Password $password
Note: As a shortcut, the -Type CodeSigningCert parameter can be specified with the New-SelfSignedCertificate command instead of explicitly adding the EKU_CODE_SIGNING string to the -TextExtension parameter.
You can use PS' cert provider to access different cert stores (user vs machine), but that won't help with your OID problem. I suggest you look at .NET support for X509 certs. Google ".net x509 certificate" and you'll find the X509Certificate class on MSDN. From there read the class documentation and any overview documentation to see if creation of OIDs is supported. If .NET doesn't support it then you'd have to use P/Invoke to invoke native Windows CNG (cryptography next generation) APIs