Writing secure code for web applications🔓
Tags: security, cybersecurity, webdev, programming
Published: 2023-10-24 09:00:00

Are you putting your web applications at risk by overlooking security in your code? A single leak can lead to devastating consequences, including data loss, financial damage, and harm to your reputation. 

With this post, you'll discover the ways and tips for protecting your web app from various attacks. Continue reading to gain the insights you need to make informed decisions. Let's get started and secure your web app.

## **Security Risks of Web Applications**


Web applications face various security risks, including injection attacks, XSS, poor authentication/session management, CSRF, broken access control, misconfigured systems, insufficient logging, and use of vulnerable components. 


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Injection attacks involve sending malicious code via user input. 

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XSS involves introducing malicious scripts into web pages. 
Poor authentication and session management lead to stolen credentials/hijacked sessions. 

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Cross Site Request Forgery (CSRF) tricks users into performing actions without knowledge. 

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Broken access control vulnerabilities can result in unauthorized access to sensitive data/functionality.

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Misconfigured systems leave the application open to attack.

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Insufficient logging and monitoring make detecting and responding to security incidents hard. 

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Using outdated/vulnerable components, such as libraries or frameworks, puts the application at risk.


## **How to write secure code for web applications**

**Input validation:** Use this technique to validate all user inputs to ensure they meet the expected format, length, and type.

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**Why it's useful:** Input validation helps prevent malicious user input from being processed by the application, reducing the risk of security vulnerabilities such as SQL injection and cross-site scripting.

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**Example:** Google uses input validation to prevent malicious user input from being processed by their applications. For example, when a user searches for a term on Google, the input is validated to ensure that it meets the expected format and length, and Google discards any malicious input. It helps protect the users and the systems from potential security threats.



**Parameterized Queries:** In order to protect the system against SQL injection attacks and keep user inputs separate from the query, use placeholders instead of directly inserting user inputs in a query.

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**Why it's useful:** It prevents attackers from altering the structure of the query and executing malicious actions on the database.

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It improves the maintainability of the code and reduces the chance of introducing security vulnerabilities.

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**Example:** Google uses parameterized queries in their applications for better security.



**Escape output:** Escape output is a technique used to prevent malicious code from being executed when data is displayed on a web page. Escaping special characters ensures that any code included in the data will be treated as plain text instead of executed.

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**Why it's useful:** With this technique, developers can ensure that user-generated data is displayed safely and securely, protecting their web applications and users from potential security threats.

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**Example:** Amazon uses escape output to protect against XSS attacks on its website. This helps to keep customer data and information secure and prevent attackers from injecting malicious scripts into Amazon's pages.



**Encryption:** Use this technique of converting sensitive data into a code to protect it from unauthorized access.

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**Why it's useful:** Protects sensitive information, such as passwords and financial data, from being viewed or used by unauthorized individuals.

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**Example:** Microsoft uses encryption to protect sensitive customer data, such as payment information, stored in their systems. They use a combination of encryption algorithms and key lengths to ensure that customer data is kept secure.



**Access controls:** Restrict access to admin pages and only give users the permissions they need to do their job.

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**Why it's useful:** Access controls are important for Implementing controls to prevent unauthorized access to confidential information and functions.

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**Example:** Uber uses access controls to ensure that only authorized employees can access sensitive customer and financial information. It helps prevent data breaches and ensures that sensitive information is only used for legitimate purposes.



**Session management:** Implement a secure mechanism to manage user sessions in a web application.

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**Why it's useful:** Improper session management can lead to a range of security vulnerabilities, such as session hijacking, where an attacker takes over a user's session, and session fixation, where an attacker can set or predict the value of a user's session ID.

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**Example:** Bank of America uses a combination of secure cookies and encryption to ensure that sessions are safe and protected from attacks.



**Third-party components:** Carefully evaluate and keep up-to-date with third-party components and libraries used in your application.

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**Why it's useful:** By using well-vetted third-party components and libraries, you can save time, mitigate the risk of security weaknesses, and focus on other areas of development.

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**Example:** Airbnb is a perfect example of a company adopting this best practice. Airbnb extensively relies on open-source software and regularly updates its third-party components to minimize security risks.



**Follow these tips to write secure code:**

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**Keep your software up to date:** Keep your programming language, frameworks, libraries and dependencies updated to avoid security vulnerabilities.

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**Use Secure Coding Practices:** Follow best coding practices and pay attention to security concerns. Refer to OWASP Secure Coding Guidelines and SANS Institute's Secure Coding Practices Quick Reference Guide.

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**Know Common Vulnerabilities:** Familiarize yourself with common security threats. Start with the OWASP Top 10.

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**Perform regular security audits:** Periodically check for new security issues and perform regular security audits to keep your app secure over time.

🤔 Have you ever experienced a security breach in one of your web applications? What did you learn from it? Let us know in the comments.