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laravel-topology

A Laravel package for password-topology-check

What is it?

The password-topology-check package provides a simple utility for converting passwords to their topologies. It also offers the ability to compare the result against the top 100 most common topologies (also known as the [PathWell Topologies][]), and reject any new passwords that match. The idea is to reduce your sites' attack planes, by making passwords harder to guess.

So what is a password topology? Well, it goes back to the "character classes" used on many sites to improve security. There are four of those, in general: upper case, lower case, digits, and symbols. The topology of a password, then, is the pattern of its character classes. P@5s, for example, has the topology upper, symbol, digit, lower, or usdl for short, while w0®D is ldsu. Ensuring your users don't re-use a PathWell Topology ensures hackers need to work through all of those before they start reaching ones they can break. Many will move on before they get that far.

Of course, even that isn't enough, just as requiring all four character classes isn't. The real benefit isn't from blocking the most common, though that's a good start. Instead, the true benefit comes from the other things we can do with it. On a per-user level, it's easy to convert both a new and an old password to their repsective topologies, then calculate the Levenshtein Distance between them. If the topology hasn't changed by a high enough factor (the default, here, is 2), the password hasn't changed enough, either. Then, as an added layer, the concept of wear-leveling can be added in to prevent users from re-using a topology already in use by other users (or their previous passwords). Wear-leveling your password topologies requires a second data store of some kind, to prevent attackers from getting too much information about which topologies are in use, but spreads your passwords out more, making them harder to crack, and reducing the chances that cracking one will help reveal several others.

OK, so what is this?

This package hooks the password-topology-check package into Laravel projects. It registers two new validation rules you can use to compare topologies and provide wear-leveling. The configuration file provides some options for how each of these features should be handled. Other than that, it tries to stay out of the way.

Usage

If your Laravel version is older than 5.5, you'll need to add the service provider to your config/app.php manually:

Unless the defaults are fine for your app, you'll want to publish the configuration and language files:

Validations: topology

Out of the box, you'll have access to two new validation rules. The first is topology, and there are two ways to use it. The first is checking the input against the internal forbidden topologies list:

The internal list can be modified directly at startup, and also automatically as passwords are created/updated – that is, they can also be wear-leveled. See the configuration section, below, for more on how to set that up.

Validations: topology:{list}

The second way to use the topology rule is checking it against a hard-coded topologies list:

Or perhaps:

Topologies with a leading ! are forbidden, while bare topologies are allowed. So the examples above would allow 555-55-5555 and 555555555, but not 555-555-555; and 555-555-5555 and (555) 555-5555 but not 555-5555 or 5555555. If any topologies are explicitly allowed (that is, if the list includes a bare topology), then only the allowed topologies will pass validation.

Validations: topo-dist:{field}

The second new validation rule is topo-dist, and checks that a new password's topology is at least the configured Levenshtein Distance from the old one's:

NOTE: Password resets can't take advantage of this functionality, as the previous password won't be available to compare against.

Topology Usage Tracking

This package also provides support for auditing your topology usage, and wear-leveling your topologies, but it takes a bit of extra setup to use. The first step is to update your ResetPasswordController to use the ResetsPasswords trait from this package instead of Laravel's. This is super simple, though – just change:

to:

The second step is to update your RegisterController to use the updateTopologyUsage method of this package's TracksTopologyUsage trait when creating new users:

Then just do the same thing you did to the RegisterController to any/all controllers you use to update users, and you're set to collect the topology usage data you need, either for auditing or for wear leveling (or potentially both?).

Configuration

The configuration file has a number of options for enabling and disabling additional features. Each is described below, along with their default values so you can decide whether to publish the configuration file or not.

• unicode (true)

  When set to true, all topology conversions will be done in Unicode mode, with full support for all the various scripts Unicode supports. It is strongly recommended to leave this set to true to properly support any users you may have with non-English keyboards and languages. The non-Unicode mode doesn't properly support even European language characters that aren't in the English character set (that is, in the ASCII character ranges). It can be set to false mostly for compatibility with applications/servers that don't support Unicode themselves, or in other legacy use cases where non-ASCII letters and numbers should be treated as symbols.

• min_lev_dist (2)

  Configures how much the password topology must change when being updated. This value is used by the topo-dist validator to determine how similar two passwords can be without failing the check. The default requires two or more changes to the topology; a value of 0 doesn't require any changes at all.

• audit_store (null)

  The database connection to use for tracking topology usage information. This should not be the same connection where your passwords are stored, as it provides hints to would-be hackers on which password topologies to brute-force against. When set to null (the default), no usage data is stored at all.

• max_topo_use (1)

  When a valid database connection is given in audit_store, any topologies with a usage at or above this level will automatically be added to the forbidden list at startup, preventing them from being used by other passwords on the same site. Since the usage data only tracks that a password is set for each topology, this covers the entire history of your site's passwords, from the moment the audit_store is created. It is recommended to increase this value rather than destroy the audit_store data, as that will provide better guarantees over time.

  When enabled, someone attempting to break into your site will only be able to crack max_topo_use passwords per topology they try.

  Setting this to 0 will allow you to collect usage data without enforcing any topology usage limits, but remember you lose the wear-leveling effect, and all restrictions on maximum cracks per topology.

• forbidden / allowed ([] / [])

  Adds or removes topologies, respectively, from the forbidden list at startup. The allowed topologies are processed first, ensuring that forbidden topologies have precedence. The PathWell Topologies are already in the forbidden list before startup, so they don't need to be listed, here.

  The topology values use the following components:

  • u: uppercase (A-Z, or any upper/title case letters in Unicode mode)
  • l: lowercase (a-z, or any letters not in upper/title case in Unicode mode)
  • d: digit (0-9, or any Unicode number)
  • s: symbol (anything else, in either mode)

  See What Is It?, above, for more details.