xss-filters-es6
Advanced tools
Secure XSS Filters - Just sufficient output filtering to prevent XSS!
Just sufficient output filtering to prevent XSS!
More Secure. Context-dependent output filters that are developer-friendly. It is safe to apply these filters like so:
document.write("<a href=" + xssFilters.uriInUnQuotedAttr(url) + ">" + xssFilters.uriInHTMLData(url) + "</a>");
In this example, the traditional wisdom of blindly escaping some special html entity characters (& < > ' " `) would not stop XSS (e.g., when url is equal to javascript:alert(1) or onclick=alert(1)).
Faster with Just Sufficient Encoding. Encode the minimal set of characters to thwart JavaScript executions, thus preventing XSS attacks while keeping most characters intact. Compared to the traditional blindly escape filter, our filters are up to two times faster, and there is no more double-encoding problems such as '&lt;'!!
Figure 1. "Just sufficient" encoding based on the HTML5 spec.
Install the xss-filters npm, and include it as a dependency for your project.
npm install xss-filters --save
Require xss-filters, and you may use it with your favorite template engine. Or just use it directly:
var express = require('express');
var app = express();
var xssFilters = require('xss-filters');
app.get('/', function(req, res){
var firstname = req.query.firstname; //an untrusted input collected from user
res.send('<h1> Hello, ' + xssFilters.inHTMLData(firstname) + '!</h1>');
});
app.listen(3000);
Simply download the latest minified version from the dist/ folder OR from the CDN. Embed it in your HTML file, and all filters are available in a global object called xssFilters.
<!doctype html><!-- You need HTML 5 mode for browser -->
...
<script src="dist/xss-filters.min.js"></script>
<script>
var firstname = "..."; //an untrusted input collected from user
document.write('<h1> Hello, ' + xssFilters.inHTMLData(firstname) + '!</h1>')
</script>
(1) Filters MUST ONLY be applied to UTF-8-encoded documents.
(2) DON'T apply any filters inside any scriptable contexts, i.e., <script>, <style>, <object>, <embed>, and <svg> tags as well as style="" and onXXX="" (e.g., onclick) attributes. It is unsafe to permit untrusted input inside a scriptable context.
A workaround, if you need to include data for JS, is to use:
<input id="strJS" value="{{{inDoubleQuotedAttr data}}}">
and retrieve your data with document.getElementById('strJS').value.
There are five context-sensitive filters for generic input:
<div> {{{inHTMLData data}}} </div><!-- {{{inHTMLComment comment}}} --><input value=' {{{inSingleQuotedAttr value}}} '/><input value=" {{{inDoubleQuotedAttr value}}} "/><input value= {{{inUnQuotedAttr value}}} />Here we use {{{ }}} to indicate output expression to ease illustrations
Whenever possible, apply the most specific filter that describes your context and data:
| Input\Context | HTMLData | HTMLComment | SingleQuotedAttr | DoubleQuotedAttr | UnQuotedAttr |
|---|---|---|---|---|---|
| Full URI | uriInHTMLData() | uriInHTMLComment() | uriInSingleQuotedAttr() | uriInDoubleQuotedAttr() | uriInUnQuotedAttr() |
| URI Path | uriPathInHTMLData() | uriPathInHTMLComment() | uriPathInSingleQuotedAttr() | uriPathInDoubleQuotedAttr() | uriPathInUnQuotedAttr() |
| URI Query | uriQueryInHTMLData() | uriQueryInHTMLComment() | uriQueryInSingleQuotedAttr() | uriQueryInDoubleQuotedAttr() | uriQueryInUnQuotedAttr() |
| URI Component | uriComponentInHTMLData() | uriComponentInHTMLComment() | uriComponentInSingleQuotedAttr() | uriComponentInDoubleQuotedAttr() | uriComponentInUnQuotedAttr() |
| URI Fragment | uriFragmentInHTMLData() | uriFragmentInHTMLComment() | uriFragmentInSingleQuotedAttr() | uriFragmentInDoubleQuotedAttr() | uriFragmentInUnQuotedAttr() |
Check out the documentations for more details.
To contribute, make changes in src/ and tests/, and then do:
npm test # run the tests
npm run-script build # build the minified version for client-side use
npm run-script docs # build the docs
This software is free to use under the Yahoo BSD license. See the LICENSE file for license text and copyright information.
FAQs
Secure XSS Filters - Just sufficient output filtering to prevent XSS!
The npm package xss-filters-es6 receives a total of 3 weekly downloads. As such, xss-filters-es6 popularity was classified as not popular.
We found that xss-filters-es6 demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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