5 Tips To Prevent Cross-Site Scripting (XSS) Attacks

Websites are constantly under threat from various types of cyber-attacks. One of the most cunning and dangerous attacks is cross-site scripting (XSS). Protecting your websites from these attacks keeps your data safe and out of harm’s way.

Any website could be the target of an XSS attack. Read on to learn about the different types of XSS attacks, how vulnerable websites become prime targets, and 5 tips to prevent cross-site scripting attacks.

Understanding Cross-Site Scripting Attacks

Cross-site scripting attacks are a type of injection incident where attackers direct malicious scripts to initially trusted websites. These scripts modify a user’s request when using their browser. This could lead to stolen data, session hijacking, and other severe consequences.

In an XSS attack, attackers exploit vulnerable websites by injecting malicious scripts into webpages viewed by other users. When an attacker executes these scripts, they perform unauthorized actions on the user’s browser. Actions include stealing cookies, capturing keystrokes, or redirecting users to malicious sites.

Types of XSS Attacks

Vulnerable websites are susceptible to threats from numerous methods. Here are some ways an attacker could carry out their XSS attack.

Reflected XSS

Reflected XSS attacks operate through an HTTP request when an attacker injects a malicious script to a victim’s browser. Users receive these kinds of XSS attacks through phishing emails or malicious links. Once clicked, these attacks have access to a user’s browser without their authorization.

These links may look legitimate, but it’s important to clarify their integrity. For example, if a user clicks on a malicious link that includes a script, the website may reflect the script back to the user's browser. Although the content may appear legitimate, the attacker now has access to the user’s data.

Stored XSS

Stored XSS attacks are more severe attacks that store themselves on the website itself. They can usually inject themselves within a database, message board, or comment field.

One way an attacker could deposit a stored XSS attack is by posting a comment containing a script on a social media platform. Every time another user views the comment, the script executes, and potentially compromises their data.

DOM-Based XSS

DOM-based XSS attacks are client-side codes that manipulate the document object model (DOM) environment in the victim’s browser. This puts the victim in a vulnerable position, as they may believe a URL is legitimate, when they are in fact putting their data at risk.

When a user clicks on a link containing this threat, it gives the attacker access to manipulate their content. For instance, an attacker could alter the URL's fragment identifier, leading the client-side script to modify the webpage content in a harmful way.

Common Vulnerabilities Leading to XSS Attacks

XSS attacks take advantage of vulnerable web applications without proper maintenance. Web applications that accept user inputs without proper checks or sanitization, for example, put themselves in harm’s way for a malicious attacker. User-submitted data needs security to prevent these attacks from surfacing.

User-submitted content with public access is also vulnerable to these attacks when not properly secured. A poorly configured web application allows HTML tags in user comments to invite harmful scripts, executing attacks when other users view the comments.

Additionally, outdated libraries and frameworks are susceptible to exploitation. Many web applications rely on third-party libraries for functionalities, which weaken the control these websites have on their data. Regularly updating and patching these components maintains security and keeps these threats at bay.

Websites that lack content security policy (CSP) are especially at risk of these types of attacks. CSP helps define what permitted content can execute on the webpages. When missing this extra layer of defense, XSS attacks could manipulate even validated inputs for their personal gain.

Unprotected websites could face the consequences of XSS attacks without their knowledge. It’s important to maintain and secure your web applications to strengthen their walls against these threats.

Tips and Best Practices To Prevent XSS Attacks

After acknowledging how these threats navigate through these vulnerable websites, the next step is to create a defense against them. Protect your web applications with these 5 tips to prevent cross-site scripting (XSS) attacks.

1. Input Validation

Validating input keeps XSS attacks off your webpages by accepting only expected values. When you keep your user inputs secure, they are less likely to contain harmful attacks. Provide scripts on your website that check input length, type, and format from users to protect their data.

2. Output Encoding

Output encoding involves converting user input into a safe format before displaying it on a webpage. Tools like the OWASP (Open Worldwide Application Security Project) Java Encoder encode users’ data so attackers can’t inject XSS attacks. Keep user input safe by encoding them against these harmful attacks.

3. Use Secure Development Frameworks

Leveraging secure development frameworks that automatically guard against XSS vulnerabilities can save time and reduce risks. Frameworks such as React and Angular have built-in mechanisms to prevent XSS attacks by default. This will minimize the chances of accidental vulnerabilities.

4. Implement Content Security Policy

Securing a CSP to your website will add a layer of security to protect your data. It will restrict the sources from loaded content and separate malicious scripts. Reduce the change of XSS risks by maintaining a website with implemented CSP.

5. Regularly Update and Patch Software

Regular maintenance and upkeep of your software, libraries, and frameworks gives you complete control of your website’s data. Stop XSS from reaching your web applications by regulating your updates and running patches on your software.

Proper Staff Training for Security Threats

Keep your team updated on the latest security measures with continuous training. When your team can recognize these threats on your platforms, you can stop the threat before it impacts a greater audience. Start practicing proper security measures and lessen your chances of falling victim to an XSS attack.

Specialized Courses

Enrolling in specialized courses, like those offered by Precision Execution, ensures your team is well-equipped to handle security challenges. For instance, our ISO training courses are just one of the courses that keep your team educated. Feel confident taking on these web threats by staying informed of safe security habits.

Cross-site scripting attacks pose a significant threat to web security. With the right knowledge and practice, you can avoid them whenever possible. Implement security measures and secure user input data by keeping a close eye on your web applications.

Empower your team with the knowledge and tools they need to secure your web applications. With a strong team and powerful software, you can protect your data from XSS attacks.