Pass the Certificate

Theory

The Kerberos authentication protocol works with tickets in order to grant access. An ST (Service Ticket) can be obtained by presenting a TGT (Ticket Granting Ticket). That prior TGT can only be obtained by validating a first step named "pre-authentication" (except if that requirement is explicitly removed for some accounts, making them vulnerable to ASREProast). The pre-authentication can be validated symmetrically (with a DES, RC4, AES128 or AES256 key) or asymmetrically (with certificates). The asymmetrical way of pre-authenticating is called PKINIT.

Pass the Certificate is the fancy name given to the pre-authentication operation relying on a certificate (i.e. key pair) to pass in order to obtain a TGT. This operation is often conducted along shadow credentials, AD CS escalation and UnPAC-the-hash attacks.

Keep in mind a certificate in itself cannot be used for authentication without the knowledge of the private key. A certificate is signed for a specific public key, that was generated along with a private key, which should be used when relying on a certificate for authentication.

The "certificate + private key" pair is usually used in the following manner

• PEM certificate + PEM private key

• PFX certificate export (which contains the private key) + PFX password (which protects the PFX certificate export)

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Practical

Evil-Winrm

For this attack you need to have access the .pfx file.

Read More: https://app.gitbook.com/o/9kzX8LPNy02cc2a878FF/s/DJRbLGcwXjABPDzT31US/~/changes/158/readme/active-directory-pentesting/crendentials/pfx-file

evil-winrm -i <domain ip> -c <certificate> -k <private key> -S

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• https://www.thehacker.recipes/a-d/movement/kerberos/pass-the-certificate

• https://book.hacktricks.xyz/network-services-pentesting/5985-5986-pentesting-winrm