Each installation of Burp generates its own CA certificate that Proxy listeners use to negotiate TLS connections. This section explains how to export, import, and create CA certificates.
You only need to manage CA certificates in the following cases:
You can export your installation-specific CA certificate for use in other tools or other instances of Burp, and import a certificate to use in the current instance of Burp:
You should not disclose the private key for your certificate to any untrusted party. A malicious attacker in possession of your certificate and key may be able to intercept your browser's HTTPS traffic even when you are not using Burp.
To regenerate a CA certificate:
You can use OpenSSL to create a CA certificate with your own details:
Enter the following OpenSSL command to create a self-signed certificate with an unencrypted 2048-bit RSA key, which is valid for 730 days:
openssl req -x509 -days 730 -nodes -newkey rsa:2048 -outform der -keyout server.key -out ca.der
Enter the following OpenSSL command to convert the key from PEM to DER:
openssl rsa -in server.key -inform pem -out server.key.der -outform der
Enter the following OpenSSL command to convert the key to a PKCS8 that contains the key:
openssl pkcs8 -topk8 -in server.key.der -inform der -out server.key.pkcs8.der -outform der -nocrypt
ca.der as the certificate file, and server.key.pkcs8.der as the key file.
Burp loads the custom CA certificate and uses it to generate per-host certificates.