As a cyberattack method, cross-site scripting (XSS) is almost as old as the internet itself. However, it still impacts just as many web-based applications today as it did 25 years ago. Discover more about how to prevent XSS attacks, what they are, and the consequences of not protecting your app from them.
XSS is a web and application security vulnerability. It enables attackers to compromise your users’ interactions with the application by circumventing its origin policy. Often, it allows attackers to disguise themselves as victim users so they can carry out actions the user can perform and access their data.
This can be especially dangerous for users with elevated privileges in your application because a hacker could gain full access to its data and functions.
The consequences of an XSS attack can be far-reaching and costly for your organization and your app’s users. These are some of the most common results of an XSS attack—and some of the most severe.
One of the most common victims of cross-site scripting attacks is your users’ data. Attackers can use XSS as an infiltration technique to steal login information, credit card numbers, and everything in between.
Because people so frequently reuse the same usernames and passwords across multiple websites and applications, the consequences of this identity theft can be far-reaching.
Using XSS to gain access to your application, attackers can embed scripts that automatically install malware on a victim’s computer. As a result, they can gain access to even more sensitive information at the user level depending on what they keep stored on their device.
Attackers can use XSS to change the content of a website. In turn, they can also use it to embed malicious links, spread misinformation, and make certain parts of your application inaccessible to users.
While this may seem like another form of vandalism, it can have even more disastrous consequences during urgent situations. For example, if your application provides services for a government entity or otherwise provides essential information during crises or natural disasters, it could potentially misdirect people on what to do and endanger their lives or property.
If your application is connected to your organization’s intranet in any way, XSS can make it easier for attackers to gain access. In turn, they can steal everything from your team’s internal documents to employee bank routing information—with consequences that range from embarrassing to disastrous for your organization.
If enough users experienced identity theft and compromised private information, your organization could be open to class-action lawsuits and other types of legal action. In addition to potentially having to pay for a legal retainer, your company could end up on the hook for fines, settlement fees, and other forms of compensation.
XSS attacks can happen to web applications with all types of coding languages or combinations thereof. Some of the languages that need XSS protection the most include:
Because the results of an attack can be disastrous for your users, brand, and bottom line, XSS prevention is more important than ever. Fortunately, there are multiple easy techniques your development team can use to protect your web-based applications from these attacks.
Setting your application up to filter out incorrect, irrelevant, or corrupted data as soon as it arrives at your server can help prevent all types of hacking attempts. For XSS attacks in particular, filtration is helpful because it can detect and block malicious or harmful code.
Developers and security teams can ensure cohesive input filtering by implementing measures both on the client side and the back end of the application. However, if you can only implement it in a single spot due to constraints, make sure the back-end input is always prioritized to keep your application safe.
While end-to-end data encryption is ideal for preventing XSS attacks, encrypting output data is extremely necessary because it protects sensitive information from prying eyes. For some industries and application types, it’s also required under regulations like HIPAA.
Encrypting your output data also helps ensure it’s protected both during transit and at rest. This is especially important if any of your users ever use public or unprotected wifi networks while they’re on your app.
Implementing automated sanitization methods is a small but valuable step developers can take to prevent XSS attacks and other security threats. It preserves data integrity and usability while neutralizing dangerous elements someone may have injected into your code so the most vulnerable parts of your application are harder to exploit.
While some sanitization methods modify the code during the process, this can change the data’s functionality or meaning and may inadvertently corrupt the data. Using sanitization methods that don’t modify your content protects your application while minimizing the risk of data loss.
The right response header can make it harder for attackers to tap into your data—while the wrong header can hold the metaphorical door open for them.
For example, using Content-Security-Policy (CSP) specifies which content sources your application will allow. This single response header goes a long way in protecting your app and users from lower-level cyber criminals or other types of attackers searching for an easy win.
Code obfuscation is one of the most trusted security techniques developers can use, even among the world’s top cybersecurity experts. These experts trust it as a baseline element of defense because it mitigates multiple types of hacking attempts—including XSS attacks.
By design, code obfuscation makes your app’s code harder for even the most seasoned hackers to understand.
Certain code obfuscation tools, such as Dotfuscator and JSDefender, also go beyond simply substituting one new name for each old name of an element. They will rename as many methods as possible and give all your elements the same name so they’re harder to debug or decode.
PreEmptive’s suite of app security and code obfuscation tools makes preventing XSS attacks easier by reducing your web application’s attack surface area. Dotfuscator and JSDefender use multiple degrees of encryption and obfuscation, including:
PreEmptive’s tools make it easy to automatically protect your web-based application and keep your users safe. They support multiple coding languages and can protect applications across multiple browsers and device types—including mobile devices—all while protecting your data and your brand.
See for yourself how PreEmptive’s code obfuscation tools can help you prevent XSS attacks. Request a free trial today