keycred

Generate and Manage KeyCredentialLinks

---

keycred is CLI tool and library that implements the KeyCredentialLink structures according to section 2.2.20 of the Active Directory Technical Specification (MS-ADTS). It also supports several deviations from the specification that are encountered in practice.

The project also contains a tool to manipulate the msDS-KeyCredentialLink LDAP attribute in order to register KeyCredentialLinks in Active Directory environments.

Features

• Supported authentication mechanism: Kerberos (password, NT hash, AES key, CCache, PKINIT), mTLS, NTLM (password or NT hash), SimpleBind (password).
• UnPAC-the-Hash: Retrieve the user's NT hash via PKINIT Kerberos authentication.
• Cross-platform compatible single binary
• Certificate otherName SAN extensions allows certificates to be used by certipy auth without specifying username and domain.
• Backup and restore functionality, that is useful when a new KeyCredentialLink should be registered for a computer account where another KeyCredentialLink is already present.
• Both the library and the tool can generate KeyCredentialLinks that are strictly compliant with the rules for validated writes (https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-adts/f70afbcc-780e-4d91-850c-cfadce5bb15c) that should be enforced when computer accounts modify their own msDS-KeyCredentialLink attribute.

Usage:

The keycred CLI tool can be used to create and manage KeyCredentialLinks, and certificate/key pairs:

$ ./keycred --help
Create and manage KeyCredentialLinks

Usage:
  keycred [command]

Available Commands:
  add         Create certificate/key and register it in LDAP
  add-raw     Register a raw DN-Binary string in LDAP
  list        List KeyCredentialLinks of a single user or all users
  remove      Remove a single KeyCredentialLink of a user
  clear       Remove all KeyCredentialLinks of a user
  auth        Authenticate and retrieve the NT hash using PKINIT (requires --pfx)
  burn        Authenticate to obtain hash/ticket and clear KeyCredentialLink (requires --pfx)
  backup      Backup all KeyCredentialLinks of a user
  restore     Restore the KeyCredentialLinks from a backup file
  register    Register the key from an existing PFX file
  parse       Parse a KeyCredentialLink in DN-Binary form
  help        Help about any command
  completion  Generate the autocompletion script for the specified shell

Flags:
      --aes-key string        Kerberos AES key
      --ccache string         Kerberos CCache file name (defaults to $KRB5CCNAME, currently unset)
      --dc string             Domain controller
      --debug                 Enable debug output
  -h, --help                  help for keycred
  -k, --kerberos              Use Kerberos authentication
  -H, --nt-hash string        NT hash
  -p, --password string       Password
      --pfx string            Client certificate and private key in PFX format
      --pfx-password string   Password for PFX file
      --scheme string         Scheme (ldap or ldaps) (default "ldaps")
      --simple-bind           Authenticate with simple bind
      --start-tls             Negotiate StartTLS before authenticating on regular LDAP connection
  -t, --target string         Target user (default is the authenticating user)
      --timeout duration      LDAP connection timeout (default 5s)
  -u, --user user@domain      Username (user@domain, 'domain\user', 'domain/user' or 'user')
      --verify                Verify LDAP TLS certificate

Use "keycred [command] --help" for more information about a command.

Additionally, this repository also includes pfxtool, which can be used to work with PFX files:

$ ./pfxtool --help
Convert certificates and keys from and to PFX files

Usage:
  pfxtool [command]

Available Commands:
  join        Create a PFX file by joining a PEM encoded key and cert
  split       Split a PFX file into PEM encoded key and cert
  decrypt     Remove the password from a PFX file
  encrypt     Encrypt the PFX file with a password
  inspect     Inspect the contents of a PFX
  create      Create a certificate/key pair and save it as a PFX file
  help        Help about any command
  completion  Generate the autocompletion script for the specified shell

Flags:
  -f, --force             Overwrite existing output files
  -h, --help              help for pfxtool
  -p, --password string   PFX password

Building

The keycred tool can be built as follows:

go build ./cmd/keycred

The PFX handling tool pfxtool can be built as follows:

go build ./cmd/pfxtool