The document discusses common security vulnerabilities in React applications such as cross-site scripting (XSS), injection attacks, CSRF attacks, malicious file uploads, insufficient authorization and authentication, distributed denial of service (DDoS) attacks, and XML external entity (XXE) attacks. It provides recommendations for how to prevent and fix each vulnerability, such as strict escaping to prevent XSS, validating all uploads, and using JSON web tokens for authorization. The document also mentions other vulnerabilities to consider like server-side rendering security and dangerous URI schemes.

1. React Security Vulnerabilities: How to
Protect Your App and Fix Them
Image Source: Login Radius
React has become the most popular JavaScript (JS) framework, and
it’s not hard to see why. It’s used by top companies like Facebook,
Netflix, Airbnb, Uber, and many more!
 10,499,785 live websites are using React.
 React with 182.4K GitHub stars & 37.2K GitHub forks.

2. If you’re new to React or are thinking about using it in your next
project, there are some important security vulnerabilities that you
must not overlook.
React Vulnerabilities provide developers with specific
recommendations on how to prevent and fix these vulnerabilities, so
you can avoid future issues and make your apps more secure.
If you’re using React, it’s important to understand these
vulnerabilities and how to protect your app against them. In this
article, we’ll explain what the React security vulnerabilities are, and
we’ll show you how to fix them.
Why Choose React?
Image Source: Medium

3. What are security vulnerabilities?
In computer security, a vulnerability is a weakness that can be
exploited by a threat actor. Vulnerabilities are often documented as
bugs in software that allow attackers to make changes to your
website or application.
These changes are typically malicious but may sometimes be used
for good, such as exposing errors in security, design, or others.
Knowing how vulnerabilities affect your site is an important step
towards protecting it from external threats.
In general, there are two types of vulnerabilities on websites: client-
side and server-side vulnerabilities. Security vulnerabilities are often
discovered by white-hat hackers and reported to the affected
company so they can be fixed.

4. In the context of web applications, security vulnerabilities can allow
attackers to steal user data, inject malicious code into an app, or take
control of a user’s account.
Moreover, in order to resolve React Vulnerabilities, you can hire
React developers. This will not only help you in resolving the
issues but will also help you in making your application error-free.
Some Common React Vulnerabilities and Its Solutions

5. There are several common security issues that you need to be aware
of when you are running or building React applications:
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Cross-Site Scripting (XSS)
When code is injected into your website by an attacker, it’s referred
to as cross-site scripting (XSS). The malicious code can change
elements on your page, steal cookies or even delete data.
It’s also harder for automated security scanners to detect these types
of issues. That makes XSS one of the most dangerous threats when
building a React app.

6. One way to protect against XSS vulnerabilities is through strict
escaping. This should be used with caution since browsers are
supposed to automatically escape HTML content already. It can also
degrade performance if used inappropriately, which could ruin your
experience with React Native mobile apps.
Injection Attacks
An injection attack occurs when an attacker injects malicious code
into an application. Hackers inject their malicious code via websites,
social media platforms, etc.
Injection attacks have been known to allow hackers access through
web pages that give them control over databases. Accessing
databases gives hackers control over credit card information and
other sensitive data for numerous applications.
It is advised that you always store your data offline in a secure server
or database, especially if it includes sensitive information about
users such as passwords or credit card numbers.
Using a dedicated server for storing your data would be ideal in
order to prevent any unwanted breaches of security from occurring.
CSRF Attacks
Cross-Site Request Forgery (CSRF) is an attack that forces a logged-
in user’s browser to send a forged HTTP request, without their
knowledge, in order to execute a malicious action.

7. CSRF attacks specifically target state-changing requests (POST, PUT
or DELETE) since those are considered more sensitive than “GET”
requests.
The attacker lures a victim on another site by using anything from
social engineering (like posting messages about kittens) all the way
up to malware that can automatically trigger attacks for them. Of
course, there are many other ways for attackers to access your users’
cookies without being on your network at all.
By limiting the number of requests that are vulnerable to CSRF
attacks, you can protect yourself from malicious links on websites.
The key design principle in this matter is using GET instead of other
types like PUT or POST because these will transform data while
being accessed by your browser, which makes them riskier forgery
methods.
Malicious File Uploads
An attacker could easily upload malicious code to your server. By
sending a form submission containing an image field, they could get
you to execute that malicious code on your server.
This is easily prevented by ensuring that all uploads are validated. If
you’re using something like Amazon S3, that service can help you
prevent malicious file uploads by adding a simple check-in to their
AWS IAM console (see below).

8. Alternately, if you’re hosting your own server, check out a module
like Nodejs-Security-Shield, which allows you to do something
similar.
Insufficient Authorization & Authentication
Authorization refers to who can access specific data, and
authentication determines whether or not that person is who they
say they are. A common vulnerability occurs when authorization
checks aren’t performed on all methods used by an app.
For example, users may be required to log in before viewing their
personal account details but not before viewing customer orders. In
these cases, hackers can exploit these privileged methods (such as
getting a list of all your customers) by simply passing an access
token to another user (for example, a customer).
To mitigate these vulnerabilities in react apps, use JWT or JSON
Web Tokens for authorization.
Distributed Denial of Service (DDoS)
This is a very common attack where a botnet (hundreds or
thousands of compromised computers) is used to flood your server
with traffic. The goal is to cause so much excess load that it takes
down your app or website.

9. As one of the most straightforward attacks, you’ll want to make sure
your app can handle large bursts of requests in order for it not to be
taken down.
A good way to defend against DDoS attacks is through server-level
request throttling — keeping track of how many simultaneous
requests are being made at any given time, checking if they’re valid,
and limiting them if they aren’t. This works especially well with
services like Cloudflare, which offers additional security layers by
default.
XML External Entity Attack (XXE)
When a web application processes XML data, it’s possible for an
attacker to cause a DoS by exhausting system resources or
consuming memory. The attack can be performed using maliciously
crafted XML content from external sources outside of your server.
In order to prevent XXE attacks, you need to use Disable External
Entities in your XML parser library (libxml2). Simply changing from
one library or parser to another won’t protect you against XXE; you
also need to upgrade libxml2 and libexpat itself if any patches were
released.
This can be done by updating your application with npm update or
yarn update on each platform you support.

10. Other security vulnerabilities to overlook when
developing React Based Application
In addition to the React vulnerabilities we’ve covered here, there are
also several other security vulnerabilities that you need to be aware
of when building React applications:
Server-side rendering
Because server-side rendering does not require you to load the
entire React app into a browser, it’s more secure than client-side
rendering.
However, you will have to keep in mind that your React code is still
vulnerable on servers, so make sure you follow best practices for
security.
For example, avoid using dynamically generated data on a server
(such as a user profile) because it cannot be validated by a browser.
Instead, save all dynamic data in a database.
Also, make sure users are logged in before running any sensitive
operations like creating accounts or updating profile data — if your
server allows for anonymous requests, somebody could perform
these operations without having any proper permission granted to
their account.
Dangerous URI schemes

11. The default behavior for navigating with links is based on a URI
scheme, which is how your browser knows how to go from one page
to another.
You can use javascript: in place of a normal URL, but that opens up
your app to XSS (cross-site scripting) attacks since that allows users
to execute scripts and code in your browser using their own data.
For example, if you have an email input, they could run
javascript:alert(‘XSS attack!’); in it, which would pop up an alert box
with a message saying XSS attack.
Obviously, you don’t want that happening, so always prevent
dangerous schemes like javascript:, VBScript:, etc., when allowing
users to navigate via links.
“DangerouslySetInnerHTML”
Because of one little mistake, an attacker could change a perfectly
harmless title tag into a block of malicious code. This example is just
one of many flaws that have been found in React’s DOM. (And since
React is so popular, more will probably be discovered.)
Fortunately, it’s not hard to avoid security vulnerabilities like these;
ReactJS developers can take simple steps to protect the apps from
attacks before they happen.
For example, you should always sanitize input data before sending it
to JavaScript functions or binding it with HTML elements. And if

12. you need access to content as plain text rather than HTML tags, you
should use third-party utilities that explicitly handle escaping for
you.
It’s important to note that these are only general tips; there are other
potential problems depending on how your application uses React
components, so don’t make assumptions!
Conclusion
As we have seen, React has become one of the most popular front-
end frameworks and libraries. Due to its rising popularity, it is also
becoming a target for malicious actors.
You need to be aware of some of the common vulnerabilities in
React applications and take suggested steps to mitigate these risks.
In addition, you should also be aware of other security
vulnerabilities that may not be specific to React but could still
impact their applications. So, you can follow the best practices and
secure your app but for this, hire React developers working in
the best React development companies. Drop us a query
below if you’re interested.