Description

csp-scan is a Python script for constructing strict content-security-policy headers based on content of HTML files in a source directory. It looks for used sources and hrefs in HTML elements for most CSP directives and outputs the header content.

Includes a warning system for unencrypted HTTP connections.

Installation

pip3 install csp-scan

Usage

cd my-frontend-src

csp-scan

Options

-d, --default-src

Value for default src directive. Default: self

-r, --report-uri

Report URI to post violations to.

-l, --literal-src

Include whole src paths in the CSP.

Contribution / forking

Contributions welcome!

Context

Directive class is initiated with a name of the directive (e.g. script-src, style-src...). Uses regex to locate specific attribute in a HTML element, given an optional pre-condition or file format.

File definitions.py creates directive objects and defines their conditions through add_search_instruction method. If you want to add a directive or modify a search condition, do it there.

style_src.add_search_instruction(
    tag = "link",
    attribute = "href",
    format = ".css"
)

This instruction will find and classify this source as style-src:

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.0/css/font-awesome.min.css"/>

But not this:

<link href="https://somecdn/js/somejsfile.js"/>

style_src.add_search_instruction(
    tag = "link",
    attribute = "href",
    condition = ("rel", "stylesheet")
)

This instruction will find and classify this source as style-src:

<link
    href="https://fonts.googleapis.com/css2?family=Montserrat:wght@100;400;500;600;700&display=swap"
    rel="stylesheet"
/>

But not this:

<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.0/css/font-awesome.min.css"/>

style_src.add_search_instruction(
    tag = "link",
    attribute = "href"
)

This instruction would find and classify all of the above examples.