Why is JavaScript Security Important?
As a primarily front-end language, JavaScript applications are especially vulnerable to attack because the application’s code is accessible to the user. This makes it much easier for an attacker to identify and exploit vulnerabilities in a front-end application. Also, an attacker has the ability to modify the code in their browser or send requests directly to the server-side applications, bypassing front-end protections.
JavaScript’s unique exposure makes it vitally important to find and fix vulnerabilities before they can be exploited by an attacker. JavaScript security helps organizations to do so by identifying known vulnerabilities in the organization’s JavaScript code.
How Does It Work?
JavaScript applications are not compiled, meaning that the source code is visible throughout its lifecycle. While this has security downsides, it also means that these applications can be easily analyzed via static application security testing (SAST).
SAST tools will analyze the source code of an application for known vulnerabilities or other issues. For example, a JavaScript security tool might look for the use of the eval() command in JavaScript, which provides unsafe access to the terminal. It may also check the dependencies used by the application for ones with known vulnerabilities or that are known to be malicious.
This code scan can be performed manually, providing a developer or security team member with a complete report on an application’s vulnerabilities. Alternatively, JavaScript security scanning can be built into automated DevOps workflows so that vulnerabilities are found and fixed before code can be committed to a repo.
Common JavaScript Security Vulnerabilities
JavaScript applications can contain a range of potential vulnerabilities. Some of the most common include the following:
- Coding Errors: JavaScript applications may contain coding errors that create vulnerabilities in the application. This is especially dangerous with client-side JavaScript because attackers can easily read the code and search for issues.
- Insecure Libraries: JavaScript applications commonly use third-party libraries available via npm or similar sources. These libraries may include vulnerabilities or malicious code that makes the application vulnerable.
- Poor Input Validation: A failure to validate user input before processing it can create injection vulnerabilities. This can lead to various types of injection attacks depending on the format of the data and its use.
- Cross-Site Scripting (XSS): XSS vulnerabilities allow an attacker to inject malicious JavaScript code into a webpage. This code can be used to steal sensitive data or take other malicious actions.
- Cross-Site Request Forgery: In a CSRF attack, the attacker tricks a user’s browser into performing requests to a website that they have already authenticated to. This could allow an attacker to change the user’s password on the site, perform a bank transaction, make social media posts, or take other undesirable actions.
- Sensitive Data Exposure: JavaScript code has the ability to access sensitive data in a web request such as the values stored in HTTP cookies. This can be used to steal session ID tokens that enable the attacker to hijack an authenticated user’s session with the webpage.
JavaScript Security Best Practices
JavaScript is prone to various potential vulnerabilities and security threats. Some best practices for avoiding these issues include the following:
- Scan JavaScript code for vulnerabilities during the development process.
- Train developers on common JavaScript security vulnerabilities and secure coding best practices.
- Validate user input before trusting or using it.
- Sanitize and encode user input to protect against injection attacks.
- Keep track of dependencies and scan them for vulnerabilities.
- Perform both server-side input validation to ensure that the server doesn’t trust potentially malicious input.
- Set the Http-Only attribute on cookies to prevent malicious JavaScript code from stealing session IDs and other sensitive information.
- Use a token to protect against CSRF attacks.
- Label cookies as “secure” to only allow them to be used by authenticated HTTPS webpages.
- Avoid unsafe coding practices such as the use of eval() or innerHTML.
Another important consideration is the option to use TypeScript instead of JavaScript. TypeScript is a superset of JavaScript and can be compiled to JavaScript code. This compilation process can help identify issues that might go undetected with JavaScript, which is an interpreted language.
JavaScript Security with CloudGuard Spectral
Check Point CloudGuard Spectral provides developers with the tools that they need to protect their JavaScript applications against attack. You’re welcome to check out this eBook to learn about protecting sensitive data in JavaScript with Spectral.
Feedback