Firefox Accounts Customs Server

This project is used by the Firefox Accounts Auth Server to detect and deter fraud and abuse.

Prerequisites

• node 0.10.x
• npm
• memcached
  • On Debian flavors of Linux: sudo apt-get install memcached
  • On Mac OS X: brew install memcached

Install

Clone the git repository and install dependencies:

git clone git://github.com/mozilla/fxa-customs-server.git
cd fxa-customs-server
npm install

To start the server, run:

npm start

It will listen on http://127.0.0.1:7000 by default.

Testing

Run tests with:

npm test

On Mac OS X, memcached must be manually started for the tests to run.

memcached &
npm test

Code

Here are the main components of this project:

• ./bin/customs_server.js: process listening on the network and responding to HTTP API calls
• ./lib/bans/: code implementing temporary bans of specific email or IP addresses and listening on the SQS API for requests
• ./lib/config/config.js: where all of the configuration options are defined
• ./lib/email_record.js, ./lib/ip_email_record.js and ./lib/ip_record.js: code implementing the various blocking and rate-limiting policies
• ./scripts: helper scripts only used for development/testing
• ./test/local: unit tests
• ./test/remote: tests exercising the HTTP API

API

See our detailed API spec.

Policies

There are two types of policies:

• rate-limiting: slows down attackers by temporarily blocking requests for 15 minutes (see config.limits.rateLimitIntervalSeconds)
• block / ban: stops attacks by temporarily blocking requests for 24 hours (see config.limits.blockIntervalSeconds)

We currently have the following policies in place:

• rate-limiting when too many emails (config.limits.maxEmails defaults to 3) have been sent to the same email address in a given time period (config.limits.rateLimitIntervalSeconds defaults to 15 minutes)
• rate-limiting when too many requests to look up account status by email address (config.limits.maxAccountStatusCheck) have been sent from the same ip address during period (config.limits.rateLimitIntervalSeconds defaults to 15 minutes)
• rate-limiting when too many failed login attempts (config.limits.maxBadLogins defaults to 2) have occurred for a given account and IP address, in a given time period (config.limits.rateLimitIntervalSeconds defaults to 15 minutes)
• manual blocking of an account (see /blockEmail API call)
• manual blocking of an IP address (see /blockIp API call)

The data that these policies are based on is stored in a memcache instance (keyed by email, ip or ip + email depending on the policy) and the code that implements them is split across these three files:

• email_record.js handles blocking and rate-limiting based only on the email address
• ip_email_record.js handles rate-limiting based on both the email and IP address of the request
• ip_record.js handles blocking based only on the IP address

The rate-limiting and blocking policies are conveyed to the auth server via the block property in the response to /check.