Reflected Cross Site Scripting

Description

Cross-site scripting (XSS) is a type of computer security vulnerability typically found in web applications which allow code injection by malicious web users into the web pages viewed by other users. Examples of such code include HTML code and client-side scripts.

🟡 Vulnerability found in /riri

This is dope

                                    GET /riri?foo=bar HTTP/1.1
                                    

                            

curl "http://perdu.com/riri?foo=bar"

None

Solutions

The best way to protect a web application from XSS attacks is ensure that the application performs validation of all headers, cookies, query strings, form fields, and hidden fields. Encoding user supplied output in the server side can also defeat XSS vulnerabilities by preventing inserted scripts from being transmitted to users in an executable form. Applications can gain significant protection from javascript based attacks by converting the following characters in all generated output to the appropriate HTML entity encoding: <, >, &, ', (, ), #, %, ; , +, -

References

• OWASP: Cross Site Scripting (XSS)
• Wikipedia: Cross-site scripting
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
• OWASP: Reflected Cross Site Scripting