System with OpenSSL installed
The *.pfx file is in PKCS#12 format and includes both the certificate and the private key. More information about the format could be found here
openssl pkcs12 -in certname.pfx -nocerts -out key.pem -nodes
openssl rsa -in key.pem -out server.key
openssl pkcs12 -in certname.pfx -nokeys -out cert.pem