XSS vs CSRF Attacks: How They Differ and How to Counter Them

Cross-site scripting (XSS) and cross-site request forgery (CSRF) attacks are among the most common dangers for modern websites. Understanding how these attacks work and how to prevent them is essential for keeping your site safe. It’s also smart to know the differences between XSS and CSRF attacks, and how to protect against both.

The good news is that there’s significant overlap in the security measures you can take to protect against XSS and CSRF attacks. While being very different in technical terms and attack vectors, good security practices go a long way towards preventing both.

On this page, we’ll explain how XSS and CSRF attacks work. We’ll also discuss the differences between them, and talk about best practices for preventing these attacks. Let’s get to it!

Part 1: XSS (Cross-site scripting)

To understand how to protect against XSS attacks, it’s important to know how they work. Let’s start with the basics.

What is an XSS attack?

An XSS attack involves injecting malicious scripts into websites by leveraging vulnerabilities in their code. XSS attacks typically use JavaScript, and they can be used to steal information like login credentials or personal details. Attackers can also hijack user sessions and perform unauthorized actions on user accounts.

There are different types of XSS attacks. The way that they work will vary depending on the attackers and the vulnerabilities they can identify on your website (if any).

XSS attacks affect all types of websites, including WordPress sites. Attackers configure bots to crawl the web and look for websites with vulnerabilities that they can exploit. Therefore, boosting website security is essential, even for new websites that aren’t getting much traffic yet.

Types of XSS attacks

There are multiple types of XSS attacks, but all of them use malicious scripts injected into the website. The web security community categorizes XSS attacks in terms of how these malicious scripts operate:

1. Stored XSS. With this type of attack, the malicious script remains on the server. Attackers do this so they can deliver the script to visitors when they access the site. This is perhaps the most dangerous type of XSS attack as it can affect large numbers of users.
2. Reflected XSS. In this instance, the attacker doesn’t store the malicious script on your site’s server. Instead, it relies on getting users to click on a URL, which will lead them to the script.
3. DOM-based XSS. This attack attempts to inject malicious code into a visitor’s browser by modifying the document object model (DOM) environment. This typically happens after users interact with the site in some way, like by submitting a form.

If you’re still a bit confused, don’t worry. In the next sections, we’ll expand on all types of XSS attacks, how they work, and the impact they can have on your website and its visitors.

How XSS attacks work

XSS attacks leverage vulnerabilities on a website to inject malicious code. These vulnerabilities can be anything, from faulty custom code to outdated WordPress plugins with known security issues.

To better understand what that means, let’s break down how XSS attacks work. The first component in any XSS attack is identifying a vulnerability on your website. 

Some of the most common elements that are at risk of attack include:

• Input fields. These elements are everywhere on the web, from comment sections to contact forms. Securing fields where users submit data is critical to protecting your website against malicious scripts.
• User cookies. These store data related to user sessions and accounts. Scripts tend to target cookies to hijack user sessions. High-quality platforms like WordPress, however, use “HttpOnly” cookies, preventing XSS attacks from stealing them. 
• Reflected content. “Reflected” content means data the website returns to users without sanitization. This process removes unsafe characters and code from user inputs to prevent attacks.

Once attackers identify a vulnerability on your website, they’ll create a script to try and exploit it. XSS attacks can have different goals, which will govern what the script does. 

Some of the most common reasons for XSS attacks include:

• Malicious redirects. Using redirects, you can send visitors from the original site to any other destination. Attackers can use this to lead visitors to phishing sites or pages that contain malware.
• Logging keystrokes. Some malicious scripts are capable of logging user keystrokes. If this happens to you, attackers can see everything that you’ve typed while the keylogger is active.  
• Session hijacking. With this type of attack, someone else can take over your session on a website where you’re logged in. Depending on what session they hijack, attackers might be able to get valuable information from users this way.
• Stealing cookie data. Cookies can store sensitive user information. Some XSS attacks use scripts to steal these cookies or read their contents.

When the script is ready, it’s time to inject it into the website through the vulnerability that attackers found. This brings us back to the three most common types of XSS attacks, which are stored, reflected, and DOM-based. 

An example of a stored XSS attack could be a user posting a malicious script on an open comments section. That could look something like this:

<script>alert('XSS')</script>

In this scenario, the vulnerability is that the website doesn’t sanitize inputs when users submit comments. Since comments are stored in the website’s database, the attack is persistent. If successful, it will execute the script whenever someone visits the page with the comments.

Once the website executes the script for a user, the attack is successful. At that point, you might find that you’ll need to assist users with cases of data theft, session hijacking, or malware originating from your website.

The impact of XSS attacks on users and businesses

The impact of XSS attacks on a business and its users cannot be overstated. If malicious actors manage to identify vulnerabilities they can use to carry out XSS attacks, your users are in danger.

That danger can come in the shape of stolen data, hijacked sessions, or malware on their devices. As the site owner, you have a responsibility to keep visitors safe. Moreover, these types of attacks can affect your reputation among your audience. Depending on the size of your business, data breaches that stem from XSS attacks might even make the news.

It’s also important to note that, under some circumstances, businesses can be liable for data breaches. The General Data Protection Regulation (GDPR) is one example of legislation that requires organizations to implement necessary measures to protect user data. Failing to do so can lead to fines and/or legal action.

Whether you’re legally liable or not, resolving vulnerabilities that can lead to XSS attacks is critical. That applies even if you have a new website with little traffic since search engines may warn users away if they detect that it poses a security risk.

Detection and prevention of XSS attacks

There are several measures you can take to protect your website from XSS attacks. The most effective ones include:

• Input validation and sanitization. This process involves validating all the data that users input on your website (through contact or comment submission forms). The website validates that the user inputs fit what is expected and then sanitizes them to remove any harmful content before sending the data.
• Content security policy (CSP). With a CSP, you can specify which sources the website can load scripts from. You can decide what sources to allowlist, so no unauthorized scripts can load on your website.
• Using tools to detect XSS vulnerabilities. There are several tools you can use to detect XSS vulnerabilities on your website. Among them, you have options like automatic site scanners, code review tools that check your codebase for security issues, and more.

If your site is on WordPress, consider using Jetpack Scan to help you detect XSS attacks.

The service automatically scans your website for security issues and vulnerabilities, and notifies you as soon as it finds anything. Plus, Jetpack Scan offers automatic fixes for many issues.

Aside from the methods above, it’s also important to foster secure coding practices among your team. Developers should be following up-to-date security guidelines and using frameworks and libraries that are secure.

Part 2: CSRF (Cross-site request forgery)

A CSRF attack involves tricking users into taking specific actions on a website or app in which they’re authenticated (logged in). Attackers can embed malicious links that trigger actions on a site with users’ authentication cookies.

To put this into perspective, imagine you’re logged into PayPal or a similar service account. You receive an email containing a suspicious link, and you click on it. The link can lead to a script, which sends a request to PayPal to send money to a different user. 

That’s an extreme example, but it’s the type of scenario that’s possible with a successful CSRF attack. For a regular website, the goal of that attack might be to steal user data, which can be devastating for the business.

Forms of CSRF attacks

All CSRF attacks follow a structure similar to what was outlined in the last section. The attacker attempts to leverage a user’s credentials to take action on a website or an app without their knowledge. 

This attack can take many forms:

1. Reflected CSRF attack. This attack vector relies on getting users to click on a link or button. The link can lead to a script, or it can contain specific instructions to send a request to the target site.
2. Login CSRF attack. With this method, attackers try to get users to log into accounts owned by them (the attackers) on the same website. The goal of this type of attack is to get users to submit sensitive information or complete transactions through the account.
3. Same-site scripting CSRF attack. With this kind of attack, malicious users exploit sites or applications trusted by your website (like by a CSP). The attack exploits that trust to send malicious requests. 
4. Cross-domain CSRF attack. With cross-domain attacks, the goal is to get users to visit a malicious website. That website sends malicious requests to the original site, leveraging users’ credentials.
5. API CSRF attack. In some scenarios, attackers can exploit vulnerabilities in API endpoints. If the API doesn’t verify the source of the request, it may perform actions on their behalf.

There are a lot of attack vectors when it comes to CSRF vulnerabilities. Some of the security fixes you can implement to prevent them also work for XSS attacks. In making your site more secure against one type of attack, you can also protect against the other.

How CSRF attacks work

To better understand how CSRF attacks work, let’s walk through the steps involved in executing them. 

The first step is user authentication. This happens through a login form or page:

This is when a user logs into the website or application being targeted by the CSRF attack. Once you log into most websites, your browser will store information about the session using cookies. 

To start with, attackers create a malicious script or link that contains the request they want to send, using your credentials. That request will execute a specific action, which can range from changing your password to deleting an account or even sending funds to another user.

With the payload ready, attackers need to find a way to deliver it. This is typically done through social engineering or spam emails including a malicious link. If you check your spam folder now, you’ll probably find several emails with suspicious links, some of which could be CSRF attacks.

Social engineering veers more on the side of sending emails pretending to originate from the target website. With this method, attackers can trick people into trusting them using branding or other details from the target website.

When users click on that link or the script runs on their browsers, they will send a request to the target website. This happens without the individual’s knowledge, and you won’t see a browser tab open or anything of the sort. The request happens in the background.

Depending on what the request is, your visitors might experience data breaches or even monetary losses. This makes preventing CSRF attacks a top priority for websites that store sensitive information or deal with large numbers of visitors.

Impact of CSRF attacks on users and businesses

CSRF attacks can have a significant impact on businesses and their users. Similar to XSS attacks, CSRF attacks can lead to data breaches, reputational damage, and even monetary losses.

For visitors, CSRF attacks can lead to direct monetary losses. For your business, the monetary losses can come from diminished user trust, or even hefty fines if you’re in breach of regulations that protect user privacy.

Some data privacy regulations put the responsibility on the website owner. That means you’re required to protect your website against security incidents like CSRF attacks. Not doing so can be seen as a form of negligence.

Detection and prevention of CSRF attacks

There are several ways to protect your website against CSRF attacks. For this section, we’ll go through each prevention method and explain how it works:

• Anti-CSRF tokens. These are tokens generated by the server when a user loads a form or performs a similar action. The tokens are stored in the user session and when they submit a request, the server can use the tokens to validate it.
• SameSite cookies. This is a security feature available in cookies, which helps control how cookies operate with cross-site requests. You can configure the SameSite attribute in cookies to limit cross-site requests to your preferences.
• Session management best practices. Following best practices with session management involves setting reasonable values for session expirations. You can also use attributes that increase cookie security, like SameSite. Some websites also force users to re-login for sensitive actions, like completing a purchase.
• Tools for detecting CSRF vulnerabilities. There are tools you can use to scan your website for CSRF vulnerabilities, as well as other security issues.

As with XSS attacks, Jetpack Scan is a strong option for detecting vulnerabilities if you use WordPress. Jetpack Scan periodically checks your website against the largest database of known WordPress vulnerabilities, which gets frequent updates.

Differences between XSS and CSRF

We’ve gone over what XSS and CSRF attacks are, how they work, and how they can affect your business. Before discussing comprehensive security practices to avoid them, let’s take a minute to compare these attacks.

Technical differences and impact

XSS and CSRF attacks are very different by nature. With the former, attackers inject malicious scripts on your website using vulnerabilities typically found in input fields. 

CSRF attacks can be a lot more involved in terms of setup and execution. With a CSRF attack, someone can send malicious requests to your website by tricking real users into helping them do it. All of that without the authentic users realizing it. 

The attack methods for targeting both types of vulnerabilities are very different. With XSS attacks, malicious actors identify vulnerabilities on your site and use them to get the server to execute or distribute malicious scripts. Sanitizing inputs and validating them can go a long way toward closing this attack vector.

CSRF attacks rely on poor session management and cookie practices. Instead of targeting the website directly, attackers rely on users as their attack vectors. They try to trick the users into sending requests on their behalf. That can be a lot more difficult to protect against than sanitizing inputs.

In terms of visibility, XSS attacks tend to have a more immediate impact. These attacks can lead to direct changes on the website or open data theft, which can draw attention from your users.

CSRF attacks tend to be less visible. This can make them harder to detect without proper monitoring and logging tools, as well as a trained workforce.

Both CSRF and XSS attacks can lead to similar outcomes for users and businesses. These include data breaches, privacy breaches, and even monetary losses (to both users and the business).

It’s also important to note that both types of attacks can lead to a loss of visitor trust. This is critical for most websites, and it’s a factor worth considering when deciding what security measures to implement.

Different methods for detecting and preventing XSS vs CSRF attacks

There is some overlap in terms of what methods you can use to detect and prevent XSS and CSRF attacks. 

Consider using vulnerability scanners and code review tools. These can help you identify vulnerabilities or security issues with your site and so you can patch them.

When it comes to prevention, your main weapons in thwarting XSS attacks will be input sanitization and validation, as well as a content security policy (CSP). Input sanitization and validation involve configuring submission fields to check if entries match the expected response and removing any potentially malicious content before submission.

A CSP, on the other hand, enables you to configure the sources your website can load scripts from. Since XSS attacks rely on getting websites to execute malicious scripts, a CSP can help you limit which options the site will execute by setting up a allowlist.

With a CSRF attack, you rely on best practices for cookies and session management for protection, as well as anti-CSRF tokens and WordPress nonces. Tokens insert unique identifiers into user cookies, so the server can have an additional data point to validate requests. If requests don’t include these identifying tokens, it stops the CSRF attack in its tracks. Nonces do a similar thing for URL — adding hashed, one-time-use-only values to the end of URLs.

When it comes to best practices for cookies and session management, it pays to set these to expire regularly. This can make it harder for attackers to target users since they’ll need to re-login often. 

For cookies specifically, you can also use the SameSite feature. This is an attribute you can add to cookies to limit cross-site requests. This can help you mitigate cross-site CSRF attacks targeting your website.

Best practices to prevent CSRF and XSS attacks

We’ve covered some detection and prevention methods for CSRF and XSS attacks individually. Now, it’s time to go over more comprehensive security practices that can help you stop these types of attacks, as well as others.

Real-time vulnerability scanning

Implementing real-time vulnerability scanning is perhaps the most consequential prevention method for CSRF and XSS attacks. A vulnerability scanner can periodically audit your website for issues that can open the door for these types of attacks.

With a vulnerability scanner, you can leverage information on known vulnerabilities from millions of websites. Most vulnerabilities are not exploited just once, so this can help mitigate most attacks on your site unless you’re dealing with a 0-day exploit.

For example, Jetpack Scan uses the WPScan vulnerability database and scans your website against it. It’s the most comprehensive WordPress vulnerability database available, and it can help you identify security issues with your site.

Learn more about vulnerability scanning.

Secure coding practices

In this case, secure coding practices encompass measures like implementing input validation and sanitization, setting up anti-CSRF tokens, and a CSP. Combined, these security measures can help prevent both CSRF and XSS attacks.

It’s also worth considering the idea of regular training on best coding practices for your team. This helps raise awareness of newly discovered attack vectors.

Regular software updates and security audits

You should regularly update any software that powers your website. For a WordPress website, that includes everything from PHP to the core installation, plugins, and themes.

Developers who follow best security practices often update software to patch vulnerabilities as quickly as possible. Keeping your site’s components up to date is the easiest way to prevent security mishaps in general.

You’ll also want to conduct security audits. These are periodical reviews of your company’s security stack and practices. An audit can be a highly time-intensive process, but it enables you to spot issues before attackers get to exploit them.

Use of a web application firewall (WAF)

A WAF helps you monitor and filter requests to your website. This prevents malicious traffic and requests, like XSS attacks.

Think of a WAF as an additional line of defense in your security stack. As you refine its rules, it becomes more effective.

Activity logging and monitoring

Implementing activity logging and monitoring is an essential security measure. Logs enable you to review activity on your website and can serve as forensic evidence when troubleshooting issues.

A big part of running large-scale or business websites involves troubleshooting and patching security issues. Activity login and monitoring tools provide a detailed overview of what’s happening on your site and any changes that occur with it.

XSS attacks can be easy to identify with activity logs. As an example, if an attacker attempts to insert a script into a comment on your site, and it’s blocked, an activity log can record this event. This could enable you to blocklist the offending IP address and prevent further attacks originating from it.

How Jetpack Security helps prevent and mitigate these attacks

Jetpack Security offers a bundle of tools geared toward making your WordPress website more secure. You’ll get a real-time backup solution, spam protection, activity logs, a WAF, and vulnerability scanning, among other security features. Let’s look at two of the tools in further detail:

Detection and prevention

Vulnerability scanning is perhaps the best prevention tool for avoiding XSS and CSRF attacks. With Jetpack Security, you’ll have access to the Jetpack Scan tool, which will automatically scan your site against the largest database of WordPress vulnerabilities. You’ll also be able to make real-time backups of your site with Jetpack VaultPress. 

Recovery

Having recent backups available is a must for any website. One way to take care of this is to automate the backup process. This means using a backup solution that runs periodically and stores the backups safely.

A real-time backup tool like Jetpack VaultPress Backup will automatically create copies of your website when you make changes to it. This means you get full coverage. Plus, you can easily restore your content with a single click.

Protect your site today

If you’re looking for a comprehensive security solution for your website, try Jetpack Security today! Built by the people behind WordPress.com, it’s the trusted solution used to enhance and secure millions of sites around the world. It’s the tool you need when you expect nothing but the best.