Welcome to drHEADer

There are a number of HTTP headers which enhance the security of a website when used. Often ignored, or unknown, these HTTP security headers help prevent common web application vulnerabilities when used.

drHEADer helps with the audit of security headers received in response to a single request or a list of requests.

When combined with the OWASP Application Security Verification Standard (ASVS) 4.0, it is a useful tool to include as part of an automated CI/CD pipeline which checks for missing HTTP headers.

Installation

To run drheader, you must have Python 3.8+ installed. The easiest way to install drheader is using pip:

$ pip install drheader

How Do I Use It?

There are two ways you could use drHEADer, depending on what you want to achieve. The easiest way is using the CLI.

CLI

For details on using the CLI, see CLI.md

In a Project

It is also possible to call drHEADer from within an existing project, and this is achieved like so:

from drheader import Drheader

scanner = Drheader(headers={'X-XSS-Protection': '1; mode=block'})

report = scanner.analyze()

Customize HTTP request

By default, the tool uses HEAD method when making a request, but you can change that by supplying the method argument like this:

from drheader import Drheader

scanner = Drheader(url='https://example.com', method='POST')

Other requests arguments

You can use any other arguments that are supported by requests to customise the HTTP request:

from drheader import Drheader

scanner = Drheader(url='https://example.com', headers={'X-API-Key': '726204fe-8a3a-4478-ae8f-4fb216a8c4ba'})

from drheader import Drheader

scanner = Drheader(url='https://example.com', verify=False)

Cross-Origin Isolation

The default rules in drHEADer support cross-origin isolation via the Cross-Origin-Embedder-Policy and Cross-Origin-Opener-Policy headers. Due to the potential for this to break websites that have not yet properly configured their sub-resources for cross-origin isolation, these validations are opt-in at analysis time. If you want to enforce these cross-origin isolation validations, you must pass the cross_origin_isolated flag.

In a project:

from drheader import Drheader

scanner = Drheader(url='https://example.com')
scanner.analyze(cross_origin_isolated=True)

How Do I Customise drHEADer Rules?

drHEADer relies on a yaml file that defines the policy it will use when auditing security headers. The file is located at ./drheader/resources/rules.yml, and you can customise it to fit your particular needs. Please follow this link if you want to know more.

Notes

• On ubuntu systems you may need to install libyaml-dev to avoid errors related to a missing yaml.h.

Roadmap

We have a lot of ideas for drHEADer, and will push often as a result. Some of the things you'll see shortly are:

• Building on the Python library to make it easier to embed in your own projects.
• Releasing the API, which is separate from the core library - the API allows you to hit URLs or endpoints at scale
• Better integration into MiTM proxies.

Who Is Behind It?

drHEADer was developed by the Santander UK Security Engineering team, who are:

• David Albone
• Javier Domínguez Ruiz
• Fernando Cabrerizo
• James Morris