Web application security - 10 threats you need to know

In this digital age, where almost every aspect of our lives and businesses relies on online solutions, data protection has become the number one priority. Hackers no longer target only large corporations; their aim is any vulnerability in the code that will allow them to steal identities or take control of a server. If you are interested in OWASP web application security, you need to learn the basics of protecting yourself against the most common attacks. The key to success is understanding the list OWASP Top 10 – a global standard for threat awareness among software developers and IT professionals.

What is the OWASP Top 10?

OWASP (Open Web Application Security Project) is a non-profit organisation that publishes a ranking of the most critical web application vulnerabilities every few years. This list is compiled based on an analysis of thousands of incidents and security vulnerabilities. Understanding these threats is the first step towards building software that is secure by design.

Below, we discuss the most important of these, as well as the security measures that every developer should implement from the very first line of code.

1. Broken Access Control

This is currently number one on the OWASP list. This occurs when a user is able to access resources for which they do not have authorisation (e.g. changing the ID in a URL allows them to view another customer’s profile).

• How can you protect yourself? Always verify permissions on the server side. Apply the principle of least privilege – by default, deny access to everything.

2. Cryptographic Failures

These are often referred to as sensitive data breaches. The problem arises when passwords or credit card numbers are transmitted in plain text or encrypted using outdated algorithms.

• How can you protect yourself? Never store passwords in plain text. Use strong hashing functions, such as bcrypt or Argon2. You must implement TLS across your entire website. If you’re not sure where to start, check out our guide: HTTPS and SSL – how do I set up a certificate?.

3. Injection (e.g. SQL injection)

A classic cyberattack. It involves sending malicious code via a form, which the database executes as a command. This can lead to a complete data breach of the user table.

• How can you protect yourself? Use prepared statements. Never trust user-supplied data – all information must be validated and sanitised.

4. Insecure Design

This vulnerability stems from errors made during the architectural planning phase. If your application lacks error-handling mechanisms (e.g. no rate limiting on the login page), it is vulnerable to brute-force attacks.

• How can you protect yourself? Carry out risk modelling during the design phase. Use ready-made, proven security patterns.

5. Security Misconfiguration

These include leaving default passwords for admin panels, enabling debug modes on production servers, or using overly detailed error messages that reveal your server’s version to a hacker.

• How can you protect yourself? Automate server deployment and hardening processes. Remove unnecessary features, code samples and default accounts.

6. Vulnerable and Outdated Components

Modern applications rely on thousands of libraries (npm, NuGet). If you are using an old version of a package with a known vulnerability, your application is vulnerable to attackers.

• How can you protect yourself? Update your libraries regularly. Use tools such as npm audit or Snyk, to monitor vulnerabilities in your dependency tree.

7. Identification and Authentication Failures

Errors relating to login and session management. Weak passwords, the lack of multi-factor authentication (MFA) or long-lived session tokens are an open invitation to intruders.

• How can you protect yourself? Implement MFA wherever possible. Ensure that tokens are handled securely. We discuss this in more detail in the article: Authorisation and authentication in Node.js.

8. Software and Data Integrity Failures

The attack involves manipulating the process of updating or transferring data. If your application downloads a plugin from an unsecured source, a hacker could replace it with malicious code.

• How can you protect yourself? Use digital signatures and verify the checksums of the files you download.

9. Security Logging and Monitoring Failures

If you do not log suspicious activity (e.g. a series of failed login attempts), you may not discover the breach until several months after the data leak.

• How can you protect yourself? Implement active monitoring and alerting. Logs should be stored in such a way that they cannot be altered by an intruder. Check whether your data has already been leaked on the website Have I Been Pwned.

10. Server-Side Request Forgery (SSRF)

This occurs when an application fetches a resource from an external URL without proper validation, allowing a hacker to „force” the server to send a request to the company’s internal, protected infrastructure.

• How can you protect yourself? Use allow-lists for the domains and IP addresses with which your server is permitted to communicate.

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How can you protect your business in 2026?

Being aware of the risks is half the battle, but the other half is taking concrete action. Security is an ongoing process – it’s not enough to simply configure a firewall once. It is essential to carry out regular penetration tests and code audits.

At 4ADStudio, we believe that security should not be an afterthought, but the cornerstone of every application. We create solutions that protect your customers’ data from the very first line of code, using best practices OWASP.

Are you concerned about the security of your application? Not sure whether your data is adequately protected against injection or XSS attacks? Get in touch with us – we’ll carry out a security audit and help you secure your digital business!