How does XSS work?

Cross Site Scripting basically is a security vulnerability of dynamic web pages where an attacker can create a malicious link to inject unwanted executable JavaScript into a Web site. The most usual case of this vulnerabilities occurs when GET variables are printed or echoed without filtering or checking their content. When a victim clicks the … Read more

What is the general concept behind XSS?

As the answers on how XSS can be malicious are already given, I’ll only answer the following question left unanswered: how can i prevent XSS from happening on my websites ? As to preventing from XSS, you need to HTML-escape any user-controlled input when they’re about to be redisplayed on the page. This includes request … Read more

AntiXSS in ASP.Net Core

The dot.net core community has a wiki on this. You can inject encoders at a controller level (in the constructor) or reference System.Text.Encodings.Web. More info can be seen here: https://learn.microsoft.com/en-us/aspnet/core/security/cross-site-scripting

Allow All Content Security Policy?

For people who still want an even more permissive posts, because the other answers were just not permissive enough, and they must work with google chrome for which * is just not enough: default-src * data: blob: filesystem: about: ws: wss: ‘unsafe-inline’ ‘unsafe-eval’ ‘unsafe-dynamic’; script-src * data: blob: ‘unsafe-inline’ ‘unsafe-eval’; connect-src * data: blob: ‘unsafe-inline’; … Read more

Protection against XSS exploits?

To prevent from XSS attacks, you just have to check and validate properly all user inputted data that you plan on using and dont allow html or javascript code to be inserted from that form. Or you can you Use htmlspecialchars() to convert HTML characters into HTML entities. So characters like <> that mark the … Read more

What is the http-header “X-XSS-Protection”?

X-XSS-Protection is a HTTP header understood by Internet Explorer 8 (and newer versions). This header lets domains toggle on and off the “XSS Filter” of IE8, which prevents some categories of XSS attacks. IE8 has the filter activated by default, but servers can switch if off by setting X-XSS-Protection: 0 See also http://blogs.msdn.com/b/ieinternals/archive/2011/01/31/controlling-the-internet-explorer-xss-filter-with-the-x-xss-protection-http-header.aspx

What does it mean when they say React is XSS protected?

ReactJS is quite safe by design since String variables in views are escaped automatically With JSX you pass a function as the event handler, rather than a string that can contain malicious code so a typical attack like this will not work const username = “<img onerror=”alert(\”Hacked!\”)” src=”https://stackoverflow.com/questions/33644499/invalid-image” />”; class UserProfilePage extends React.Component { render() … Read more