Building Secure Applications: Common Vulnerabilities and How to Avoid Them

Posted on August 26th, 2024

In this digital world, most businesses are going online to reach their massive number of customers through their web applications. Customers make payments and save their crucial personal information on the web app.

Nowadays, some hackers steal personal information from the web app and sell it on the online market. So, we will understand the common vulnerabilities of web applications and learn how to avoid them to increase their business strength.

What are Common Vulnerabilities and How to Avoid Them?

In 2024, there’s a 10% increase in security breaches than 2023 according to IBM’s report. Web application vulnerability means security weaknesses of web apps which allows hackers to steal information or manipulate the source code.

Now, web applications play a vital role in businesses like e-commerce to data management. So, it’s the great chance for the cyber attackers to steal the personal information of customers.

There are several common vulnerabilities that affect web applications which are essential for developers, security professionals, and businesses alike to protect sensitive data and maintain the integrity of the system.

Cross-Site Scripting (XSS)

Cross-site scripting occurs when an attacker injects malicious scripts on the web applications which can be seen by the customers. This trick is used to steal cookies, session tokens, and to perform actions on behalf of customers without their consent.

XSS vulnerabilities typically arise when web applications accept untrusted input and include it in web pages without performing adequate validation or escaping.

There are three primary types of XSS: Stored XSS, where the malicious script is permanently stored on the target server; Reflected XSS, where the malicious script is reflected off a web server, such as in an error message or search result; and DOM-based XSS, where the vulnerability exists in client-side code rather than server-side code.

How to Avoid XSS?

There are many ways to avoid cross-site scripting (XSS):

• Filter all the inputs on the web application on arrival. When any customer inputs their data, strictly check as much as possible to filter out the cyber attackers.
• Implementing a Content Security Policy (CSP) helps to mitigate XSS by specifying which sources of content are trusted. By restricting the execution of scripts to those from trusted domains, CSP adds an extra layer of defence even if XSS vulnerabilities are present.
• Use HTML Purifier Web Hosting for your web application in order to remove all the malicious codes with thoroughly audited.
• While output encoding is critical, input sanitization also plays a role. Sanitizing inputs ensures that harmful data never gets processed in the first place. For example, removing or escaping potentially dangerous characters like <, >, and & from user inputs can help prevent XSS.

SQL Injection

SQL injection is an injection attack which makes it possible to execute malicious SQL statements. These statements control the database server of a web application. It occurs when a cyber attacker manipulates the web application’s input fields like contact forms or URL parameter, to inject malicious SQL code into the database query.

This results in data leakage, data modification, unauthorized access, or even complete control over the database.

How to Avoid SQL Injection?

One of the most effective defenses against SQL Injection is the use of parameterized queries, also known as prepared statements. By binding user inputs as parameters, the database treats them strictly as data rather than executable code, preventing any embedded SQL from being executed.

ORMs are tools that help developers interact with databases using the language of the application (e.g., Python, Java). ORMs automatically parameterize queries, providing a layer of protection against SQL Injection. However, developers must still be cautious when using raw queries within ORMs.

Insecure Direct Object References

Insecure direct object references (IDOR) is a crucial vulnerability that can lead to a serious cyber attack on your web application. This type of vulnerability occurs when an application provides direct access to objects based on user-supplied inputs.

This happens when an application exposes internal implementation objects, such as files, database records, or keys, without properly verifying the user’s permissions.

How to Avoid IDOR?

Ensure that the application verifies that the user has the appropriate permissions for every object they attempt to access or modify.

Use indirect references or mapping between user-visible identifiers and internal identifiers that are not easily guessable or manipulable.

Avoid exposing sensitive identifiers in URLs or request parameters whenever possible.

Session Fixation

Session fixations are the web-based cyber attacks where the cyber attackers take advantage of the vulnerability of a web-browser’s session management system to steal a real person’s session.

Cyber attackers force or trick new users to use their session ID which was already made by the attacker and send it to them using the link or something. The user is not aware of any attack, so the user will directly log into the application. Now, the attackers will know that the user has logged into the web application. They will access the user’s account without their consent.

How to Avoid Session Fixation?

Every time the application makes a new session ID after a new user logs in, which neglects all the previous session IDs.

Encrypting the communication between the user’s browser and the server prevents an attacker from capturing the session ID.

HttpOnly flags help prevent session IDs from being accessed via client-side scripts or transmitted over insecure connections.

Local File Inclusion (LFI)

Local File Inclusion is a security weakness in web applications. It allows an attacker to include files on a server through the web browser. The vulnerability is typically the result of insufficient input validation or sanitization, where user input is passed to a file inclusion function without proper checks.

The web application takes user input, such as a file path or filename, to include or load a file. If the application does not properly validate this input, an attacker can manipulate it to load arbitrary files from the server. The attacker can use directory traversal techniques (e.g., ../../) to access files outside the intended directory.

How to Avoid Local File Inclusion?

Ensure that each and every user input goes for validation.

The web application should only allow the inclusion of files from a predefined list.

In some programming languages, disable functions that allow arbitrary file inclusion if they are not needed.

Remote Code Execution (RCE)

Remote Code Execution attack allows attackers to execute random code on the server which leads to full system compromise and unauthorized access to sensitive data. RCE attacks can be made through injecting malicious code on the server through user inputs or exploiting weaknesses in code libraries.

Remote code execution attacks will have several consequences like leakage of personal information, denial of service (DoS), illegal cryptocurrency mining, and execution of malware.

How to Avoid Remote Code Execution?

The web applications have to strictly check each and every detail of user input.

Keep an updated version of your operating software and third-party software, and also make sure that you have the latest security patches.

Avoid building SQL or command-line queries dynamically with user input.

Broken Access Control

Broken Access Control means lack of access controls which allows unauthorized users to access restricted pages and resources. Broken access control is similar to IDOR (Insecure Direct Object Reference), the main difference is that IDOR allows an attacker to access the database while broken access control allows an attacker to access special functions and resources.

How to Avoid Broken Access Control?

The web applications have to make proper access control by setting the proper authentication and authorization of new users to access the specific functions and resources.

The web application has to deny all access by default; users must be able to access every page of the web application if they want.

Conduct thorough code reviews to ensure that access control mechanisms are correctly implemented and not bypassable.

What is the Biggest Security Threat to a Web Application?

Finding the biggest security threat to a web application varies according to the type of web application and its unique vulnerability. The biggest security threat to a web application is SQL injection. This happens when cyber attackers find the weakness of a web application and then inject harmful files into the server to steal personal information from that web application’s customers.

By performing this, the web application owner can suffer serious consequences such as unauthorized access to data, data leakage, or even complete loss of the application.

SQL Injection is particularly dangerous because it can bypass login systems, access or change sensitive data, and perform administrative tasks on the database. It can impact any application that uses user input to interact with a database, making it a crucial vulnerability to fix.

Injection attacks are common because of poor input validation and the improper use of secure coding methods. Preventing them requires careful input checks, the correct use of secure coding practices, and regular security testing.

Conclusion

In conclusion, building secure web applications means actively looking for and fixing common security issues. By learning about threats like SQL injection, cross-site scripting (XSS), and weak authentication methods, developers can follow best practices to make their applications safer.