OpenSSL print OIDs from Certificate

Question

I'm confronting an issue, I'm trying to see the OIDs of the EKU of a certificate. But when running

openssl x509 -in certificate.crt -text -noout

I get

X509v3 Extended Key Usage:
TLS Web Client Authentication, Microsoft Smartcard Login

instead of

1.3.6.1.4.1.311.20.2.2

Do you know a way of printing it to the screen, I've seen another post but using code and I want it using command line only.

I've tried all the -certopt that might be useful, but I didn't get the result wanted.

Answer 1

After sometime away from the subject, I found that it was OpenSSL that replaces OIDs with aliases

So you just have to decode the certificate manually.

To do that, you can use any ASN.1 parser or x509 decoder, I recommend CyberChef gchq.github.io/CyberChef

for example if I use the basic OpenSSL tool :

X509v3 extensions:
            .....

            X509v3 Extended Key Usage: 
                TLS Web Client Authentication, Microsoft Smartcard Login
            .....

And with CyberChef rfc x509 parser :

Extensions
         .....

         extKeyUsage :
            clientAuth, 1.3.6.1.4.1.311.20.2.2

         .....

and if you want more detail, you can use the rfc ASN.1 parser.

SEQUENCE
          ObjectIdentifier extKeyUsage (2 5 29 37)
          OCTETSTRING, encapsulates
            SEQUENCE
              ObjectIdentifier clientAuth (1 3 6 1 5 5 7 3 2)
              ObjectIdentifier (1 3 6 1 4 1 311 20 2 2)