Easiest way to generate PFX certificate (Windows)

certificate-authoritycertutilssl-certificate

At the moment to generate PFX Certificate, I use openssl and:

  • Generate a CSR with its private key
  • Connect to my CA website (Microsoft CA), and submit CSR along with (san:dns=) additional attribute.
  • From certificate authority I issue the pending certificate (Base 64).
  • Convert my private key PKCS8 to PKCS1
  • Create a PEM (private key, host cert, intermediate cert, and root cert)
  • and FINALLY convert my PEM to PKCS#12 (.pfx file)

This process is quite lengthy and I believe I am wasting lots of time doing so.

Can anyone please let me know what is the faster way to get a certificate chain (pfx) signed from an internal Microsoft CA ?

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Best Answer

Right, Well I scripted it then.

I still believe that there is an easier way with certreq and powershell but here is the bash script. Requirements: Cygwin, standard UNIX utilities, clip, openssl

#!/bin/bash
iexplore='/cygdrive/c/Program\ Files\ \(x86\)/Internet\ Explorer/iexplore.exe';
printf "\033c";
echo -e "This function automates IIS7 certificate generation for <YourCompany>";
type openssl > /dev/null 2>&1 || { 
    echo "Cannot find OpensSSL, it is required to generate certificates.  Aborting..." 1>&2;
    exit 1
};
openssl version;
echo -e "\n";
read -p "What is the server hostname (NOT FQDN!): " Hostname;
if [[ $Hostname =~ ^[A-Za-z0-9]+$ ]]; then
    echo -e "Server name:\t"$Hostname"\nFQDN:\t\t"$Hostname".<yourDomain>\n";
else
    echo ""$Hostname" doesn't look quite right... Exiting";
    sleep 3;
    exit 1;
fi;
mkdir ~/Desktop/certs_temp > /dev/null 2>&1;
cd ~/Desktop/certs_temp;
echo "
[ req ]
default_md = sha512
default_bits = 2048
default_keyfile = rui.key
distinguished_name = req_distinguished_name
encrypt_key = no
prompt = no
string_mask = nombstr
req_extensions = v3_req
input_password = testpassword
output_password = testpassword

[ v3_req ]
basicConstraints = CA:false
keyUsage = digitalSignature, keyEncipherment, dataEncipherment
extendedKeyUsage = serverAuth, clientAuth
subjectAltName = DNS:"$Hostname"

[ req_distinguished_name ]
countryName = AU
stateOrProvinceName = NSW
localityName = Sydney
0.organizationName = <OrgName>
organizationalUnitName = <OrgUName>
commonName = "$Hostname".<YourDomain>" > openssl.cfg;
openssl req -out openssl.csr -new -newkey rsa:2048 -nodes -keyout pk.key -config openssl.cfg > /dev/null 2>&1;
openssl rsa -in pk.key -out openssl.key > /dev/null 2>&1; rm pk.key;
echo -e "Now, upload this Code Signing Request to the Internal Certificate Authority: \n\t- The CSR content has been copied into your clipboard\n\t- You do not require to set any subject alternate name\n\t- Once submitted, open "Certificate Authority" via MMC (<ServerName>), issue pending certificate and export it (Open / Details / Copy To File) Base64 to ~/Desktop/certs_temp/openssl.cer\n";
eval $iexplore https://<ServerName>/certsrv/certrqxt.asp;
cat openssl.csr | clip;
read -p "Press [Enter] when openssl.cer certificate has been place in ~/Desktop/certs_temp";
if [ -f 'openssl.cer' ]; then
    cat openssl.cer >> openssl.key;
    echo '
-----BEGIN CERTIFICATE-----
<CompanyIntermediate>
-----END CERTIFICATE-----
-----BEGIN CERTIFICATE-----
<CompanyRoot>
-----END CERTIFICATE-----' >> openssl.key;
    mv openssl.key ""$Hostname".pem";
    echo "Converting PEM Chain certificate to PKCS#12 (.pfx)";
    openssl pkcs12 -export -out ""$Hostname".pfx" -in ""$Hostname".pem";
    explorer .
else
    echo "Cannot find openssl.cer in ~/Desktop/certs_temp... Exiting";
    sleep 3;
    exit 1;
fi

The script :

  1. Generates a private key and code signing request based on a config file.
  2. Copies the CSR in the clipboard and open IIS webpage to request the cert.
  3. Prompts the user for issuing the pending certificate and export it base64
  4. Creates PEM, then export it as PKCS#12 (.pfx)

Note: You have to change the path for Internet Explorer for Win 32bit and have to replace < ServerName > specific tags.

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