The split method chops the password into parts if the password contains a colon, then the total credentialsParts.length > 2. The HTTP Basic Authentication spec does not restrict passwords this way.
var credentialsParts = new Buffer(parts[1], 'base64').toString().split(':');
if (credentialsParts.length !== 2) {
return reply(Boom.badRequest('Bad header internal syntax', 'Basic'));
}