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, changes to entryCSN and modifyTimestamp on existing entries can be 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 ignore when comparing changes to existing entries.

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

Requirements

• Python 3.10+.
• 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 from a clone of this repository, this script:

1. Creates (if necessary) a Python virtual environment in /opt/ldap-watchdog.
2. Installs LDAP Watchdog from the clone into that virtual environment, with the dependency versions pinned in requirements.txt.
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

LDAPS connections verify the server certificate and check that it is valid for the host name or IP address in LDAP_WATCHDOG_SERVER. For a private CA, set LDAP_WATCHDOG_CA_CERTS_FILE to a readable PEM CA bundle; in Docker, mount the bundle into the container and use its container path. A self-signed server certificate can be used as the bundle itself. If the certificate can't be provided or doesn't match the server's name, LDAP_WATCHDOG_TLS_VERIFY=false turns verification off; anyone on the network path can then impersonate the server and capture the bind password. For a server without TLS, use an ldap:// URL or set LDAP_WATCHDOG_USE_SSL=false.

Control User

A failed control check logs an error and skips that comparison. The next poll compares against the most recent successfully retrieved snapshot; changes from a rejected comparison are not replayed. A failed LDAP retrieval instead preserves the previous snapshot and is retried on the next poll. Failure to retrieve the initial snapshot stops the process.

Slack Integration

Slack delivery is best effort: HTTP and network failures are logged to stderr, and monitoring and console output continue. Failed notifications are not queued or retried.

Ignored Entries and Attributes

These filters apply to attribute changes on entries present in both snapshots. Entry additions and deletions are always announced with all retrieved attributes, including for ignored UUIDs.

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_TLS_VERIFY='true'
export LDAP_WATCHDOG_REFRESH_RATE='60'
export LDAP_WATCHDOG_NETWORK_TIMEOUT='30'
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.

Development

Install the package with Slack support and run the regression tests:

pip install ".[slack]"
python -m unittest discover -s tests

requirements.txt pins every dependency for the Docker image and install.sh. After changing the dependencies in setup.py, regenerate it with pip-compile --extra=slack --output-file=requirements.txt setup.py.

License

This project is licensed under GPL3.0.