express-sanitizer

An express middleware for Caja-HTML-Sanitizer, which wraps Google Caja sanitizer.

A useful complement to the express-validator -- to fill a gap now that XSS sanitization support has been removed from that module's parent node-validator.

Installation

yarn add express-sanitizer

or

npm install --save express-sanitizer

Usage

Import the module

const expressSanitizer = require('express-sanitizer');

Mount the middleware below the express.json() (or, prior to express v4.16, bodyParser()) instantiation and above mounting of your routes

app.use(express.json());
 
// Mount express-sanitizer middleware here
app.use(expressSanitizer());
 
app.post('/', function(req, res, next) {
  // replace an HTTP posted body property with the sanitized string
  const sanitizedString = req.sanitize(req.body.propertyToSanitize);
  // send the response -- res.body.sanitized = " world"
  res.send({ sanitized: sanitizedString });
});

Output

The string

'<script>hello</script> world'

will be sanitized to ' world'.

Limitations

This is a basic implementation of Caja-HTML-Sanitizer with the specific purpose of mitigating against persistent XSS risks (note the borderline abandonware comments in that repo).

Caveats

This module trusts the dependencies to provide basic persistent XSS risk mitigation. A user of this package should review all packages and make their own decision on security and fitness for purpose.

Changelog

v1.0.5

• Unit tests (better late than never)

v1.0.4

• Merged PR #3 from Brian M. Jemilo II

v1.0.3

• Updated README to base example on an express-generator scaffolded application

v1.0.2

• Updated sanitizer dependency to 0.1.3
• Merged PR #4 from @ScottRamsden

v1.0.1

• Updated sanitizer dependency to 0.1.2

v1.0.0

• Update to v1

v0.1.1

• Merged PR removing unused dependency

v0.1.0

• Initial release

Contributors

• Mark Andrews 20metresbelow@gmail.com
• Patrick Hogan patrick@callinize.com
• Scott Ramsden @ScottRamsden
• Brian M. Jemilo II jemiloii@jemiloii.com

License

Copyright (c) 2019 Mark Andrews 20metresbelow@gmail.com, MIT License