LDAP Watchdog

Overview

LDAP Watchdog is a tool designed to monitor record changes in an LDAP directory in real-time. It provides a mechanism to track and visualize modifications, additions, and removals to user and group entries, allowing users to correlate expected changes with actual changes and identify potential security incidents. It was created with OpenLDAP and Linux in mind, however it may work in other implementations of LDAP. It is written in Python and only requires the ldap3 library.

This software was written by Joshua Rogers.

If you're interesting in any of the following, then LDAP Watchdog is for you:

• Know what's going on in your LDAP directory on-demand with Slack webhook integration.
• See new hires, leavers, and promotions as they appear in LDAP.
• Monitor when and what HR is doing.
• Detect unauthorized changes in LDAP.
• Monitor for accidentally leaked data.
• Detect when users are logging in and out of LDAP.

In addition to monitoring for modifications, additions, and removals in an LDAP directory, it can be configured to ignore specific attributes, or even fine-tuned to ignore fine-grained attributes depending on their old/new values.

The changes that are monitored can either be forwarded to a slack webhook or output to the terminal (or both). Optional colored output is also supported.

Previously named LDAP-Stalker (because monitoring changes of an LDAP directory is an excellent way to stalk changes in a company: learn about promotions before they're announced, new hires, leavers, etc.), a blog post about the details and history of this project can be found here.

Examples (No Filtering)

Note: in the below examples, entryCSN and modifyTimestamp can be completely ignored by setting LDAP_WATCHDOG_IGNORED_ATTRIBUTES=entryCSN,modifyTimestamp.

Terminal (with color) output:

Slack output:

Features

1. Real-time Monitoring: LDAP Watchdog continuously monitors an LDAP directory for changes in user and group entries.

2. Change Comparison: The tool compares changes between consecutive LDAP searches, highlighting additions, modifications, and deletions.

3. Control User Verification: LDAP Watchdog supports a control user mechanism, triggering an error if the control user's changes are not found.

4. Flexible LDAP Filtering: Users can customize LDAP filtering using the LDAP_WATCHDOG_SEARCH_FILTER environment variable to focus on specific object classes or attributes.

5. Slack Integration: Receive real-time notifications on Slack for added, modified, or deleted LDAP entries.

6. Customizable Output: Console output provides clear and colored indications of additions, modifications, and deletions for easy visibility.

7. Ignored Entries and Attributes: Users can specify UUIDs and attributes to be ignored during the comparison process.

8. Conditional Ignored Attributes: Conditional filtering allows users to ignore specific attributes based on change type (additions, modifications, deletions).

Requirements

• Python 3.7+.
• The ldap3 package. If using a Slack webhook, the requests package is also required.

Installation

PyPI

pip install LDAP-Monitor

To include Slack webhook support:

pip install LDAP-Monitor[slack]

Docker

docker pull megamansec/ldap-monitor

Or from GitHub Container Registry:

docker pull ghcr.io/megamansec/ldap-monitoring-watchdog

From Source

git clone https://github.com/MegaManSec/LDAP-Monitoring-Watchdog.git
cd LDAP-Monitoring-Watchdog
pip install ".[slack]"

Usage

Running with pip install

export LDAP_WATCHDOG_SERVER='ldaps://ldaps.intra.lan'
export LDAP_WATCHDOG_BASE_DN='dc=mouse,dc=com'
export LDAP_WATCHDOG_USERNAME='Emily'
export LDAP_WATCHDOG_PASSWORD='qwerty123'
ldap-watchdog

Or using python -m:

python -m ldap_watchdog

Running with Docker

docker run -d \
  -e LDAP_WATCHDOG_SERVER='ldaps://ldaps.intra.lan' \
  -e LDAP_WATCHDOG_BASE_DN='dc=mouse,dc=com' \
  -e LDAP_WATCHDOG_USERNAME='Emily' \
  -e LDAP_WATCHDOG_PASSWORD='qwerty123' \
  -e SLACK_WEBHOOK_URL='https://hooks.slack.com/services/[...]' \
  -e LDAP_WATCHDOG_IGNORED_ATTRIBUTES='modifyTimestamp,phoneNumber,officeLocation,gecos' \
  megamansec/ldap-monitor

Systemd Installation (Debian-based)

A Debian-based installation script, install.sh, is provided. When run as root, this script:

1. Creates (if necessary) a Python virtual environment in /opt/ldap-watchdog.
2. Installs LDAP Watchdog from PyPI into that virtual environment.
3. Creates an environment file at /etc/ldap-watchdog.env for configuration.
4. Installs and enables a systemd service (/etc/systemd/system/ldap-watchdog.service) that runs ldap-watchdog in the background.
5. Configures logging to /var/log/ldap-watchdog.log and /var/log/ldap-watchdog-error.log.
6. Sets up log rotation in /etc/logrotate.d/ldap-watchdog.

You may optionally pass a single argument to install.sh to set the SLACK_WEBHOOK_URL:

sudo ./install.sh "https://hooks.slack.com/services/[...]"

After installation, edit /etc/ldap-watchdog.env to configure the LDAP connection settings, then restart the service:

sudo systemctl restart ldap-watchdog

Configuration

All configuration is done via environment variables. The following variables are supported:

General Settings

Environment Variable	Description	Default
LDAP_WATCHDOG_SERVER	LDAP server URL (e.g. ldaps://ldaps.intra.lan)	""
LDAP_WATCHDOG_BASE_DN	Base Distinguished Name for LDAP searches	""
LDAP_WATCHDOG_USERNAME	LDAP username for authentication. Leave empty for anonymous bind.	""
LDAP_WATCHDOG_PASSWORD	LDAP password for authentication. Leave empty for anonymous bind.	""
LDAP_WATCHDOG_USE_SSL	Set to true to use SSL, false otherwise	true
LDAP_WATCHDOG_SEARCH_FILTER	LDAP filter for user and group entries	(&(|(objectClass=inetOrgPerson)(objectClass=groupOfNames)))
LDAP_WATCHDOG_SEARCH_ATTRIBUTE	Comma-separated list of attributes to retrieve. *,+ is used by default to include operational attributes.	*,+
LDAP_WATCHDOG_REFRESH_RATE	Time interval in seconds between consecutive LDAP searches	60
LDAP_WATCHDOG_DISABLE_COLOR_OUTPUT	Set to true to disable colored terminal output	false

Control User

Environment Variable	Description	Default
LDAP_WATCHDOG_CONTROL_UUID	UUID of a control user whose changes trigger an error if not found. If set, this user should always have some type of change when the LDAP directory is retrieved.	""
LDAP_WATCHDOG_CONTROL_USER_ATTRIBUTE	Specific attribute to check for changes in the control user. If set, this attribute must have changed for the control UUID user.	""

Slack Integration

Environment Variable	Description	Default
SLACK_WEBHOOK_URL	Slack Webhook URL for notifications. Requires the slack extra (pip install LDAP-Monitor[slack]).	None
LDAP_WATCHDOG_SLACK_BULLETPOINT	Bullet point character used in Slack and console output	\u2022

Ignored Entries and Attributes

Environment Variable	Description	Default
LDAP_WATCHDOG_IGNORED_UUIDS	Comma-separated list of UUIDs to ignore during comparison	""
LDAP_WATCHDOG_IGNORED_ATTRIBUTES	Comma-separated list of attributes to ignore during comparison	""
LDAP_WATCHDOG_CONDITIONAL_IGNORED_ATTRIBUTES	JSON string of attributes to conditionally ignore (see below)	{}

Conditional Ignored Attributes

The LDAP_WATCHDOG_CONDITIONAL_IGNORED_ATTRIBUTES variable accepts a JSON string where keys are attribute names and values are lists of values to ignore:

export LDAP_WATCHDOG_CONDITIONAL_IGNORED_ATTRIBUTES='{
  "objectClass": ["posixAccount"],
  "memberOf": ["cn=mailing-list-user,ou=Accessgroups,dc=mouse,dc=com", "cn=interns,ou=Accessgroups,dc=mouse,dc=com"],
  "organizationalStatus": ["researcher"]
}'

Example Configuration

export LDAP_WATCHDOG_CONTROL_UUID='a71c6e4c-8881-4a03-95bf-4fc25d5e6359'
export LDAP_WATCHDOG_SERVER='ldaps://ldaps.intra.lan'
export LDAP_WATCHDOG_BASE_DN='dc=mouse,dc=com'
export LDAP_WATCHDOG_USERNAME='Emily'
export LDAP_WATCHDOG_PASSWORD='qwerty123'
export LDAP_WATCHDOG_USE_SSL='true'
export LDAP_WATCHDOG_REFRESH_RATE='60'
export LDAP_WATCHDOG_DISABLE_COLOR_OUTPUT='false'
export LDAP_WATCHDOG_IGNORED_UUIDS='e191c564-6e6d-42c1-ae51-bda0509fe846,8655e0d9-ecdc-46ce-ba42-1fa3dfbf5faa'
export LDAP_WATCHDOG_IGNORED_ATTRIBUTES='modifyTimestamp,phoneNumber,officeLocation,gecos'
export LDAP_WATCHDOG_CONDITIONAL_IGNORED_ATTRIBUTES='{"objectClass":["posixAccount"],"memberOf":["cn=mailing-list-user,ou=Accessgroups,dc=mouse,dc=com","cn=interns,ou=Accessgroups,dc=mouse,dc=com"],"organizationalStatus":["researcher"]}'
export SLACK_WEBHOOK_URL='https://hooks.slack.com/services/[...]'

ldap-watchdog

Limitations

1. The LDAP_WATCHDOG_CONDITIONAL_IGNORED_ATTRIBUTES configuration may unfortunately hide important changes that are not intended to be hidden. This may happen if an attribute has a single value which is changed. This is because conditional ignored attributes will hide changes to the attribute both when the value is changed to as well as from the ignored value; for example, if a user is a memberOf cn=mailing-list-user,ou=Accessgroups,dc=mouse,dc=com which gets changed to cn=super-administrator,ou=Accessgroups,dc=mouse,dc=com, it will be missed.
2. Similar to #1, there is no real way to determine whether a change is really a change in some cases, or a removal and then addition in the same time. In theory, it doesn't really matter, however it's important to note.

License

This project is licensed under GPL3.0.