This article discusses several important points to consider when preventing XSS attacks in Vue applications. Among them are stored XSS, persistent XSS, and reflective XSS. Implementing all of these best practices in your Vue applications is imperative. This article also discusses OWASP recommendations for the prevention of cross-site scripting. By the end of this article, you should have a basic understanding of the OWASP guidelines for web security.
Stored XSS or Persistent XSS
Two main methods exist when it comes to preventing the exploitation of stored or persistent XSS in Vue. First, you must ensure that the HTML you include in your code is sandboxed. This is not always possible, so you must ensure that the HTML is properly wrapped and protected. In addition, you should not allow users to write their Vue templates, as this may expose your code to similar dangers.
Moreover, sanitization libraries have a set of rules to decide whether a given HTML tag can be allowed or not. The rules may allow certain HTML tags while rejecting others. Hence, sanitization libraries are not effective against all forms of JavaScript or CSS, but they can help prevent cross-site scripting attacks. In Vue, a v-html directive introduces raw HTML into a component, making it vulnerable to XSS attacks.
Reflected XSS Attacks
You should not mount Vue to the entire HTML page to prevent reflected XSS attacks. This will expose it to various vulnerabilities, ranging from user-provided URLs to unclean content. Therefore, it is important to sanitize any URLs provided by the user before including them in the application. Also, you should avoid allowing users to write their Vue templates, as this opens the door to the same types of attacks.
A common mistake developers make is using v-html to pass untrusted inputs to the application. The v-html directive is not secure and does not have a way to sanitize any inputs sent through it. The good news is that several solutions are available on NPM, including vue-sanitize. If you’re using v-html, you should consider implementing the sanitize-html extension instead.
OWASP
Vue prevents XSS by not allowing script injection, which means that the browser must not be vulnerable. Instead, escaping is done via native browser APIs. The dangers associated with XSS are not limited to Vue but affect any website that uses user-generated content. For example, Twitter is known to accept short messages from users, but this feature also allows an attacker to inject a malicious script that compromises the browser.
Using the v-html directive is a particularly dangerous approach to preventing XSS. This is because v-html does not allow sanitization of user-supplied content. Using a sanitized iframe will solve this problem. In addition, allowing users to write their Vue templates could also present similar risks. However, this solution is not a one-size-fits-all solution.
Cross-site scripting in a Vue application
To avoid vulnerabilities, it’s important to mount your Vue application only on certain parts of an HTML page. This will expose your application to risks if the HTML page contains unclean content. In addition, allowing the user to write their Vue templates can expose your application to similar risks. So, it would help if you were wary of this approach and carefully evaluated the risks before implementing it.
One of the main problems with web applications nowadays is the vulnerability of cross-site scripting (XSS). A website renders user-generated content directly into the page without sanitizing it first. Scripts can be injected via regular user input or URL parameters. In Vue, this vulnerability is through the v-html directive, which outputs raw HTML into a component.
References: https://dev-academy.com/vue-xss/
