How do JavaScript frameworks impact the security of applications?

With almost 14 million active developers and 98% of all websites using it, JavaScript provides the building blocks for web applications – and it’s easy to see why it’s so popular. This fundamental programming language offers the flexibility to create interactive web apps that bring online applications to life. While this ubiquity has led to the development of intuitive, streamlined frameworks that make it even easier to build dynamic web applications, it’s also JavaScript’s Achilles heel.

The JavaScript framework's popularity attracted the attention of cybercriminals who target their innate vulnerabilities on an industrial scale, compromising the security of the applications they underpin.
 

JavaScript frameworks 

Building complex, interactive web applications from scratch can be overwhelming without an in-depth understanding of coding. JavaScript frameworks break down technical barriers by providing access to a pre-written, reusable code set. This standardized structure creates a blueprint for building web applications using predefined tools, components, and best practices. Novice developers can leverage these frameworks to create robust, scalable, and maintainable applications without learning how to code.

Hybrid mobile apps frameworks – such as React Native, NativeScript, Apache Cordova, and Ionic – illustrate how JavaScript can be leveraged to build powerful apps that run on Android and iOS without extra effort. For instance, NativeScript apps are built using JavaScript or any language that converts to JavaScript, such as TypeScript.

JavaScript framework vulnerabilities

Applications built using JavaScript frameworks are executed on the client side, exposing them to vulnerabilities that can be exploited to execute malicious code, steal cookies, session tokens, or other sensitive information that leads to identity theft or hijacking. Let’s explore ten of the most common vulnerabilities and how to avoid them using client-side practices and policies:

Cross-Site Scripting (XSS)

Malicious scripts are injected into trusted applications and executed by unsuspecting users’ browsers. There are three different types of XSS attacks:

• Stored XSS: Once injected, the malicious script is permanently stored on the target server.

• Reflected XSS: The user unknowingly sends a malicious script to a web server via a URL.

• DOM-based XSS: The client-side scripts in a web page modify the DOM and execute the attacker's payload.

Mitigation: Validate and sanitize all client-side user input used as part of HTML output and encode user-generated content before displaying it on web pages to stop the browser from interpreting it as executable code or active web links.

Cross-Site Request Forgery (CSRF)

Attackers transmit unauthorized commands from a user that the web application trusts, such as changing account details or making purchases. A malicious script or link forces the user to perform actions like submitting a form or making a request without their knowledge or consent.

Mitigation: Use anti-CSRF tokens to ensure requests originate from the correct source and implement same-site cookies to restrict cookies to requests from the same domain. Cross-Origin Resource Sharing (CORS) policies restrict which domains can send requests to a web server, ensuring only trusted origins can interact with sensitive endpoints. For critical operations, users should always be required to re-authenticate.

Security Misconfiguration

Poor security settings in the application can make it easier for attackers to exploit vulnerabilities. For instance, improperly configured Content Security Policies (CSP) intended to prevent XSS attacks may be too permissive, or failure to disable unnecessary JavaScript functions or expose sensitive information can create attack vectors.

Mitigation: Proper configuration requires robust CSPs, diligent management of security settings, and regular reviews and updates to align with best practices and minimize exposure to attacks.

Flawed Code via JavaScript Supply Chain

Web applications typically incorporate code from diverse sources, including third-party libraries – any flaw in this source code heightens the risk of a cyber-attack. Once these flawed packages are included in a development project, the vulnerabilities can propagate throughout the application, potentially compromising security, performance, and functionality. Attackers exploit these flaws to gain unauthorized access, steal sensitive data, or disrupt services.

Mitigation: Enforce strong code and webpage integrity policies that include endpoints, networks, the cloud, and mobile devices, so only known and reliable third-party code can run. Gain client-side visibility by using webpage inventory technology that actively monitors this angle.  Use automated tools to ensure the reliability of third-party dependencies by actively monitoring them.

Intentional Code Alterations by Threat Actors

By manipulating JavaScript code, attackers can exploit web applications by executing malicious activity, including harvesting user credentials, redirecting users to phishing sites, or installing malware. These modifications can be introduced using techniques like XSS attacks and compromising third-party libraries or supply chains. 

Mitigation: Implement resilient source code protection that obfuscates the code, such as code integrity checks, secure coding standards, and regular audits of the codebase and third-party dependencies.

Web Skimming

These client-side attacks occur when cybercriminals inject malicious JavaScript code onto a web application to compromise sensitive data – typically payment card data – inputted by users into checkout pages and other online forms. Applications are compromised by targeting assets originating outside their security perimeter, including all client-side web assets – the files and resources that are downloaded and executed by a user's web browser when they use an app.

Mitigation: To securely collect data from users via web forms, they must be designed to incorporate proactive security measures, including data encryption, multi-factor authentication (MFA), spam protection, and secure communication protocols like HTTPS and SSL/TLS.

Formjacking

Malicious JavaScript code is inserted into a web application, hijacking its form functionalities, such as checkout or login forms, to siphon off user data. Formjacking exploits the trust that users have in well-known, legitimate web applications. Consequently, the attack can often go undetected for a prolonged period.

Mitigation: Regularly patch and update the app's software, plugins, and extensions, ensure it uses a secure connection to keep data safe during transmission, and regularly scan the app and server logs for vulnerabilities and suspicious activities.

Magecart

This is a form of e-skimming attack focused on injecting digital credit card skimmers into e-commerce and payment applications to compromise sensitive payment data. Attackers typically exploit vulnerabilities in third-party scripts or gain access to the app's infrastructure to plant malicious code. Once embedded, it silently intercepts and exfiltrates payment data to servers controlled by the attackers.

Mitigation: Gain client-side visibility using webpage inventory technology that actively monitors the client side, looking for signs of malicious behavior.

Session Hijacking

Attackers gain unauthorized access to a user's active session with a web application by exploiting vulnerabilities to steal cookies and other session tokens to impersonate legitimate users. This can occur through methods like man-in-the-middle attacks whereby, without adequate encryption, data exchanged between the user and the server can be intercepted and altered by attackers.

Mitigation: Implement strong encryption to secure cookies and ensure proper input sanitization.

JavaScript Sniffers

JavaScript sniffers are malicious scripts (malware) injected into a web application's code to intercept and steal sensitive information. They exploit vulnerabilities in the app’s security, such as unpatched software, weak access controls, or insecure third-party integrations, allowing attackers to inject the malware directly or through compromised third-party scripts. Once deployed, the malware silently captures transactional data from forms or other input fields as users interact with the compromised app.

Mitigation: Conduct regular code audits, patch and update the app's software consistently, ensure secure handling of third-party resources, and use CSPs to limit the execution of untrusted scripts.

Fortifying Frameworks: JavaScript Client-side Security

JavaScript’s well-deserved reputation as the programming language of choice for web application development has been achieved despite innate vulnerabilities that can lead to severe consequences – from unauthorized access to sensitive data to manipulation of application functionality. 

Amid this wide client-side attack surface, the fundamental JavaScript frameworks that streamline web application development can compromise their security. Effective mitigation of this multidimensional threat requires robust client-side security practices and policies that reinforce these frameworks by constantly patching and updating software, regularly monitoring script behaviors and web pages for changes, and being diligent when selecting and implementing third and fourth-party scripts.