SimpleTOTP

SimpleTOTP is a SimpleSAMLphp auth processing filter that enables the use of the Time-Based One-Time Password Algorithm (TOTP) as a second-factor authentication mechanism on either an Identity Provider or Service Provider (...or both!).

This has been tested with Google Authenticator on iOS and Android.

Why?

While a there are a few two-factor authentication modules that already exist for SimpleSAMLphp, they are all implemented as authentication sources.

As an auth processing filter, this module is flexible in a number of ways:

• agnostic to where the TOTP secret is stored
• can be enabled on select Service Providers or an entire Identity Provider

Usage

Like any other auth process filter, this module needs to be configured in an authproc array in either config.php or in the metadata for a particular service provider or identity provider.

Prerequisites

The secret_attr needs to be available in the attribute payload as it is used to generate the token for comparison. This can be added using other auth process filters to look up an external databases of sorts (SQL, LDAP, etc).

After the module has been called, the attribute will be moved out of the user attribute array. As a safety precaution an extra step should be taken ensure this attribute is removed. This can be done using the core:AttributeAlter filter or similar.

Example

Placed in either config.php's authproc or in the appropriate metadata entity:

10 => array(
	'class' => 'simpletotp:2fa',
	'secret_attr' => 'ga_secret', //default
	'enforce_2fa' => false, //default
	'not_configured_url' => NULL,  //default
),

Placed in config.php authproc as one of the last functions to be processed:

99 => array(
	'class' => 'core:AttributeAlter',
	'subject' => 'ga_secret',
	'pattern' => '/.*/',
	'%remove',
),

Example of how it can work with example-userpass module. Below config goes in authsource.php This module is enabled by default but if it is not make sure you create a file called enable inside modules/exampleauth directory.

	'example-userpass' => array(
		'exampleauth:UserPass',
		'student:studentpass' => array(
			'uid' => array('test'),
			'ga_secret' => array('4HX4WBKVIJWDUV5I'),
			'eduPersonAffiliation' => array('member', 'student'),
		),
	),

After logging in with username: student password: studentpass, you will be challenged for TOTP. 4HX4WBKVIJWDUV5I is a secret key that can be generate by visiting /simplesaml/module.php/simpletotp/generate_token.php

A random one will be generated everytime. You can also use the QR code to register your IdP with apps such as FreeOTP or Google Authenticator etc.

NOTE: for TOTP to work you MUST ensure that the clock on your server is in sync. If it is not, a matching token will never be generated and authentication will fail.

Installation

Via Git

A simple git clone in the SimpleSAMLphp module directory is all that is required.

Via Composer

composer.phar require aidan/simplesamlphp-module-simpletotp

TODO

• improve usage documentation with examples using external database(s) as data sources
• add basic brute force prevention