DMPS

Does My Password Suck!?

Purpose

Credential stuffing is a very real threat to web application security and it's important that businesses are doing their best to protect their users from passwords that been been seen in known breaches.

This library is designed to be hooked into your login or change password forms to ensure that users aren't using or setting passwords seen in known breaches. This is achieved by sending the first five characters of a SHA-1 copy of the user's password to Have I Been Pwned's API and matching it against the result set that is returned.

TL;DR: This adds breached password detection to your web apps.

Note: This library is intended for browser use only. In future versions it might support Node but the intent is to keep the library free from dependencies.

Installation

Install the dmps package using npm or yarn.

npm i -S dmps

yarn add dmps

Import the Module & Configure

Import the module and instantiate the class. TypeScript types are available.

import Dmps from 'dmps'

const pw = new Dmps(config)

Methods

Check Password (pw.check())

pw.check returns a promise that resolves true or reject with an Error. See Error Handling below.

const pw = new Dmps(config)

pw.check('password') // Promise<true>

Hash Password (pw.hashPassword())

Exposes the internal password hashing method.

const pw = new Dmps(config)

pw.hashPassword('password') // '5BAA61E4C9B93F3F0682250B6CF8331B7EE68FD8'

Error Handling

Methods in the dmps library use custom errors so you can better handle responses.

  try {
    await pw.check('password')
  } catch (e) {
    switch(e.name) {
      case 'UnexpectedHttpResponseError':
        // A response other than 200 was received from HIBP
      case 'TimedOutError':
        // The timeout was reached
      case 'InvalidPasswordError':
        // The password is either not a string or is empty
      case 'BreachedError':
        // The password has been breached
        // You can use e.count on this error type
        console.log(`Password has been breached ${e.count} times.`)
    }
  }

Configuration

DMPS can be configured accordingly:

| Option | Type | Default | Purpose | | :------------------|:---------------------|:--------------------------------------------------|:------------------------------------------------------- | | endpoint | string (optional) | https://api.pwnedpasswords.com/range/ | Substitute the HIBP endpoit for your own. | | timeout | number (optional) | 5000 | Timeout on the check. | | userAgent | string (optional) | dmps-js | Change the UserAgent to represent your service. | | resolveOnTimeout | boolean (optional) | false | Resolve instead of erroring on timeout. |

endpoint

In some environments a business may choose to either proxy or host their own HIBP endpoint. The script will pass the first five characters of the SHA-1'd password to the last url part — for example: https://api.pwnedpasswords.com/range/{hash}

timeout

To ensure that the user experience isn't adversely affected by the additional HTTP request it is recommended to set a timeout. The default timeout is 5000 milliseconds, but you may want to change this depending on your situation.

userAgent

The HIBP API Acceptable Use Policy requires that user agent "accurately describe the nature of the API consumer such that it can be clearly identified in the request". It is recommended that you change this, however it will default to dmps-js.

Please also refer to the licensing requirements for using the Passwords API. Accreditation isn't required but it is welcomed by HIBP.

resolveOnTimeout

Setting this to true will resolve the check method promise if it times out which can assist in some programming situations. This is not recommended as you should try and handle this in your codebase.