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I am using Windows.location.href=URl to navigate to MVC controller method from java script. I want to avoid any XSS attack when redirecting. what should i do

HamzaNig
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Sarang Mohalkar
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2 Answers2

2

You can write your own XSS sanitising function 

function encodeHTML(s) {
    return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/"/g, '&quot;');
}

window.location.href = encodeHTML(URI);
Abhisar Tripathi
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It should be very easy. I have ready made solution for you. First of all some theoritical understanding

RULE #0 - Never Insert Untrusted Data Except in Allowed Locations

<script>...NEVER PUT UNTRUSTED DATA HERE...</script>   directly in a script

<style>...NEVER PUT UNTRUSTED DATA HERE...</style>   directly in CSS

RULE #1 - HTML and JavaScript Escape Before Inserting Untrusted Data into HTML Element Content

HTML ...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE... JS

<script>alert('...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...')</script>     inside a quoted string

Escaping as in

& --> &amp;
 < --> &lt;
 > --> &gt;
 " --> &quot;
 ' --> &#x27;     &apos; not recommended because its not in the HTML spec (See: section 24.4.1) &apos; is in the XML and XHTML specs.
 / --> &#x2F;     forward s

lash is included as it helps end an HTML entity

Ensure returned Content-Type header is application/json and not text/html.

Coming to the coding portion

Following would help you

private String killXSS(String value) {
        if (value != null) {
            // NOTE: It's highly recommended to use the ESAPI library and uncomment the following line to
            // avoid encoded attacks.
            // value = ESAPI.encoder().canonicalize(value);

            // Avoid null characters
            value = value.replaceAll("", "");

            // Avoid anything between script tags
            Pattern scriptPattern = Pattern.compile("<script>(.*?)</script>", Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("");

            // Avoid anything in a src='...' type of expression
            scriptPattern = Pattern.compile("src[\r\n]*=[\r\n]*\\\'(.*?)\\\'", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");

            scriptPattern = Pattern.compile("src[\r\n]*=[\r\n]*\\\"(.*?)\\\"", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");

            // Remove any lonesome </script> tag
            scriptPattern = Pattern.compile("</script>", Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("");

            // Remove any lonesome <script ...> tag
            scriptPattern = Pattern.compile("<script(.*?)>", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");

            // Avoid eval(...) expressions
            scriptPattern = Pattern.compile("eval\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");

            // Avoid expression(...) expressions
            scriptPattern = Pattern.compile("expression\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");

            // Avoid javascript:... expressions
            scriptPattern = Pattern.compile("javascript:", Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("");

            // Avoid vbscript:... expressions
            scriptPattern = Pattern.compile("vbscript:", Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("");

            // Avoid onload= expressions
            scriptPattern = Pattern.compile("onload(.*?)=", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");
        }
        return value;
    }

Make sure every request you are sending to server is stripped through above mentioned code and you will never be victim of XSS.

Kunal Vohra
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  • Optimally you should sanitize the data BEFORE injecting it anywhere in the output. This GUARANTEES your security. – Xiddoc Jun 13 '21 at 09:17
  • @Xiddoc well in the answer same sanitisation is done. We have two type of sanitisation per my understanding. 1 per business rule specific and 2 per the industry standards. Answer provided was referred by OWASP site when given. – Kunal Vohra Jun 15 '21 at 14:22
  • And per the reference of original question, mentioned things done would suffice the job – Kunal Vohra Jun 15 '21 at 14:23
  • Check [this](https://stackoverflow.com/a/54398564/11985743) for OWASP standards – Xiddoc Jun 15 '21 at 14:56
  • Well I disagree. Please refer OWASP site and not a reference to another answer. – Kunal Vohra Jun 15 '21 at 15:01