brick

Automatically disable EZproxy user accounts via incoming webhook requests.

Table of contents

• Project home
• Status
• Overview
  • EZproxy's purpose
  • brick's purpose
  • brick in action
  • The end result
• Features
  • Current
  • Missing
  • Future
• Changelog
• Documentation
  • TL;DR
  • Hands-on / demo
  • Index
• License
• References

Project home

See our GitHub repo for the latest code, to file an issue or submit improvements for review and potential inclusion into the project.

Status

Alpha quality; most MVP functionality is present, but a number of improvements to make this tool useful to a broad audience are still missing.

Overview

EZproxy's purpose

Per the EZproxy Wikipedia page:

EZproxy is a web proxy server used by libraries to give access from outside the library's computer network to restricted-access websites that authenticate users by IP address. This allows library patrons at home or elsewhere to log in through their library's EZproxy server and gain access to resources to which their library subscribes, such as bibliographic databases.

brick's purpose

brick is an application that is intended to run alongside an existing EZproxy instance and a Splunk monitoring system in order to disable (suspected) compromised user accounts.

brick in action

When Splunk, identifies suspect account behavior (based on sysadmin-specified thresholds), it delivers a webhook payload to a HTTP endpoint on brick for processing. brick then disables the suspect user account and (optionally) generates one or more notifications listing the action(s) taken. All actions are logged.

At this point, the associated user sessions can be optionally (and automatically) terminated using two approaches:

1. using (not officially documented) ezproxy binary subcommand
2. using the provided fail2ban config files

If using native termination support, all active user sessions associated with the reported username will be terminated using the kill subcommand provided by the official ezproxy binary. The sysadmin will need to provide the path to the ezproxy binary and the associated Active Users and Hosts "state" file where sessions are tracked.

If installed and configured appropriately, fail2ban can be used to to monitor the reported users log file and ban the associated IP address. This ban should be for MaxLifetime minutes (EZproxy setting) + a small buffer to force active sessions associated with the disabled user account to timeout and terminate.

The end result

The net effect is that reported user accounts are immediately disabled and compromised accounts can no longer be used with EZproxy until manually removed from the disabled users file.

NOTE: brick has not been designed to identify user accounts directly. Instead, this application but rather relies on other systems (currently limited to Splunk) to make the decision as to which accounts should be disabled.

The hope is to extend payload format support to include Graylog and other popular log monitoring systems in the future.

See also:

• High-level overview
• our other documentation for further instructions

Features

Current

• Highly configurable (with more configuration choices to be exposed in the future)

• Optional automatic (but not officially documented) termination of user sessions via official ezproxy binary

• Optional filtering of JSON payload sender IP Addresses

  • default setting is to accept payloads from any IP Address, relying on host-level firewall rules to prevent receipt from rouge systems
  • if a list of trusted IP Addresses is provided, those IP Addresses will be the only ones allowed to submit JSON payloads

• es CLI application

  • small CLI app to list and optionally terminate user sessions for a specific username
  • intended for quick troubleshooting or as an optional replacement for logging into the admin UI to terminate user sessions for a specific username

• Supports configuration settings from multiple sources

  • command-line flags
  • environment variables
  • configuration file
  • reasonable default settings

• Ignore individual usernames (i.e., prevent disabling listed accounts)

• Ignore individual IP Addresses (i.e., prevent disabling associated account)

• User configurable logging settings

  • levels, format and output (see configuration settings doc)

• Optional notifications

  • Microsoft Teams
  • Email
  • generated for multiple events
    • alert received
    • disabled user
    • ignored user
    • ignored IP Address
    • error occurred
  • configurable retries and delay between retries
  • configurable notifications rate limit (used to respect remote API limits)

• Logging

  • Payload receipt from monitoring system
    • logging of rejected payloads
    • logging of accepted payloads
  • Action taken due to payload
    • username ignored
      • due to username inclusion in ignore file for usernames
      • due to IP Address inclusion in ignore file for IP Addresses
    • username disabled

• contrib files/content

  • intended solely for demo purposes
    • postfix
    • docker
      • Maildev container
    • sample JSON payloads for use with curl or other http/API clients
    • demo environment doc
    • slides from group presentation/demo
    • shell scripts to setup test/demo environment
  • intended for demo and as a template for production use
    • fail2ban
    • brick
    • rsyslog
    • systemd

The contrib content is provided both to allow for spinning up a demo environment in order to provide a hands-on sense of what this project can do and (at least some of the files) to use as a template for a production installation (e.g., the fail2ban config files). At some point we hope to provide one or more Ansible playbooks (GH-29) to replace the shell scripts currently used by this project for setting up a test/demo environment.

Missing

Known issues:

• Documentation
  • The docs are beginning to take overall shape, but still need a lot of work

Future

Priority	Milestone	Description
Low	Unplanned	Potential merit, but are either low demand or are more complex to implement than other issues under consideration.
Medium	Future	Considered to have merit and sufficiently low complexity to fit within a near-future milestone.
High	vX.Y.Z	Milestones with a semantic versioning pattern reflect collections of issues that are in a planning or active development state.

Changelog

See the CHANGELOG.md file for the changes associated with each release of this application. Changes that have been merged to master, but not yet in an official release may also be noted in the file under the Unreleased section. A helpful link to the Git commit history since the last official release is also provided for further review.

Documentation

TL;DR

1. Install dependencies, including fail2ban
2. Setup environment
   1. create new service account/group
   2. create log directory
   3. create cache directory for disabled users file
   4. set ownership, permissions
   5. customize config files
      • brick
      • fail2ban
      • ...
   6. deploy config files (including systemd unit file, logrotate conf, ...)
3. Build brick
4. Deploy brick
5. Configure EZproxy to use new disabled users file
6. Configure Splunk alerts
7. Test!

Hands-on / demo

These resources were used to provide a demo to our team prior to gather feedback, well before deployment plans were locked-in. The notes are detailed (perhaps overly so) and were used as a reference before/during the team demo.

The PowerPoint is much like it sounds and the demo scripts are used to (reasonably) quickly prepare a local "throwaway" VM for the demo. Reviewing this material may help you decide if this project is a good fit for use at your institution.

• demo notes (verbose)
• demo scripts
• Slides used in live demo
  • PowerPoint file
  • PDF file

Index

Order	Name	Description
1	Why?	High-level overview of application design and purpose
2	Demo	Presentation material for a local demo that I will provide to showcase existing and future functionality.
2	Build	Building/compiling brick
3	Deploy	Deploying brick
4	Configure	Settings supported by brick
5	Fail2Ban	Brief coverage on integrating with Fail2Ban (to monitor and take action on events recorded by brick)
6	EZproxy	Brief coverage on integrating with EZproxy (suggested settings, using files generated by brick)
7	Rsyslog	Brief coverage on adding a Rsyslog action to route messages from brick
8	Endpoints	Current endpoints offered by brick
9	Splunk	Brief coverage on configuring an alert to send to brick (NOTE: highly environment specific)
10	References	Various reference material used while developing brick

License

Taken directly from the LICENSE and NOTICE.txt files:

Copyright 2020-Present Adam Chalkley

https://github.com/atc0005/brick/blob/master/LICENSE

Licensed under the Apache License, Version 2.0 (the "License"); you may not use
this file except in compliance with the License. You may obtain a copy of the
License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed
under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
CONDITIONS OF ANY KIND, either express or implied. See the License for the
specific language governing permissions and limitations under the License.

References

Various references used when developing this project can be found in our references doc.