contrast-agent 3.2.2

Contrast Security's agent for Python web frameworks

Contrast Python Agent

Overview

The Contrast Python agent provides runtime protection of Django, Flask and Pyramid web applications.

Online Documentation

For the most up to date documentation visit Contrast Open Docs

About Python

The Python agent is a WSGI- and framework-specific middleware that's compatible with the most popular web application frameworks. The agent's goal is to be fully WSGI compatible along with other web frameworks.

Protect Mode

In Protect mode, the Python agent inspects HTTP requests to identify potentially harmful input vectors from its position within the middleware stack. During the request, the agent monitors database queries, file writes and other potentially damaging actions resulting from the request. At the end of the request, the agent checks the rendered output for successful attacks, and can block a successful attack from being forwarded to the application user. The service sends the details of the attack to the Contrast application, which then sends you an alert and displays attack details in the interface.

Using the Agent

To start protecting your application, download the Python agent and create a configuration file as described in the Installation section. The Python agent is installed as a standard Python package, and communicates with a standalone Contrast Service that runs outside your application.

Supported Technologies

The Python agent supports Python versions 2.7+ and 3.5 to 3.8. It supports the following web frameworks:

• Django: 1.10+, 2.0+, 3.0+ (Django 2 and 3 are Python 3 only)
• Flask: 0.10 - 0.12 and 1.0+
• Pyramid: 1.4.5 and 1.9+ (Beta)
• Pylons: 1.0+

Note: The Python agent is meant to be WSGI compatible. It may be compatible with other WSGI applications as long as the guidelines are followed.

Database Support

The Python Agent has database support for:

• SQLite3 (sqlite3 and pysqlite2)
• PostgreSQL (psycopg2)
• MySQL (pymysql)
• Cassandra 1.X (pycassa)

NoSQL Support

The Python Agent has NoSQL support for:

• Mongo (pymongo)

ORM Support

The Python Agent has ORM support for:

• SQLAlchemy (SQLAlchemy)
• Flask-SQLAlchemy (Flask-SQLAlchemy)

OS Support

Agent testing is done on 64-bit OSX and 64-bit Linux. The agent has no C dependencies, and may work in other operating system environments.

Installation

To install the Contrast agent into your Python application, you must complete the following steps.

1. Add contrast-agent-[version].tar.gz to the application's requirements.txt (see Standard Setup).
2. Provide the agent with a valid contrast_security.yaml configuration file (see Configuration).

Standard Setup

The contrast-agent-[version].tar.gz is a standard packaged Python library that you can add to the application's requirements.txt.

To use Contrast, add this line to your application's requirements.txt after downloading the agent:

./path/to/contrast-agent-[version].tar.gz

After editing the requirements.txt you can install normally with:

pip install -r requirements.txt

Manual Setup

If you would prefer to install the Contrast agent manually, download the contrast-agent-[version].tar.gz file to a local directory and run:

pip install ./path/to/contrast-agent-[version].tar.gz

Middleware Inclusion

To hook into incoming requests and outbound responses, you need to add the Contrast middleware to your application. To do this, use the appropriate guidance for your framework.

Django

For Django 1.10+, 2.0+, and 3.0+, add the following to your settings.py file:

MIDDLEWARE = [
  # OTHER MIDDLEWARE
  'contrast.agent.middlewares.django_middleware.DjangoMiddleware'
]

Older versions of Django have a different architecture for middlewares. For Django 1.6 to 1.9, add the following in your settings.py file:

MIDDLEWARE_CLASSES = [
  # OTHER MIDDLEWARE
  'contrast.agent.middlewares.legacy_django_middleware.DjangoMiddleware'
]

Flask

import Flask
from contrast.agent.middlewares.flask_middleware import FlaskMiddleware as ContrastMiddleware

app = Flask(__name__)
app.wsgi_app = ContrastMiddleware(app)

Pyramid

from pyramid.config import Configurator

config = Configurator()
config.add_tween('contrast.agent.middlewares.pyramid_middleware.PyramidMiddleware')

WSGI

from contrast.agent.middlewares.wsgi_middleware import WSGIMiddleware as ContrastMiddleware

# other app code

app = get_wsgi_application()
app = ContrastMiddleware(app)

Pylons

from pylons.wsgiapp import PylonsApp
from contrast.agent.middlewares.wsgi_middleware import WSGIMiddleware as ContrastMiddleware

app = PylonsApp()
app = ContrastMiddleware(app)

Next Steps

Once the installation process is complete, you must provide the agent with a contrast_security.yaml configuration file as outlined in the Configuration section below.

Configuration

The Python agent and Contrast Service use a YAML file to configure their behavior.

File Location

The configuration file must be named contrast_security.yaml or contrast_security.yml no matter where it's located. The Python agent loads the configuration YAML from the following paths in order of precedence:

1. Any path saved in the environment variable CONTRAST_CONFIG_PATH
2. The settings directory within the current directory (e.g., ./settings/contrast_security.yaml)
3. The current working directory (e.g., ./contrast_security.yaml)
4. Within the server's etc/contrast/python/ directory (e.g., /etc/contrast/python/contrast_security.yaml)
5. Within the server's etc/contrast/ directory (e.g., /etc/contrast/contrast_security.yaml)

The agent and service may share a common configuration file, but only some options and sections are applicable to each process.

Configuration Options

Download a standard configuration file from the Contrast Dashboard. You must place the file in one of the standard locations described above, and define the following fields, at a minimum:

agent:
  service:
    host:
    port:

For additional information, see the Contrast Open Docs.

Optional Start the Service Manually

The Python agent will attempt to start the Contrast Service on it's own. However, if you wish to run the Service separately please follow these steps.

Like the contrast-agent, the contrast-service requires a configuration file. Place the configuration YAML file in the same directory as the contrast-service.

The contrast-service is an executable Go Service that can be run directly from the application directory. This can be done by executing:

• Linux/OSX: ./contrast-service
• Windows: ./contrast-service.exe