?? Top Web Application Attacks Every Cybersecurity Enthusiast Must Know

In today's digital landscape, web applications are prime targets for attackers. With the increasing reliance on cloud platforms, APIs, and web-based services, the attack surface is expanding rapidly. This article breaks down the most common web application attacks, how they work, and how to prevent them—making it a must-read for cybersecurity professionals, developers, and enthusiasts alike.

? 1. Directory Traversal

?? What is Directory Traversal?

Also known as path traversal, this attack allows a malicious user to access restricted directories and execute commands outside the web server's root directory. By manipulating URL parameters, attackers can navigate through directories and access sensitive files (e.g., /etc/passwd, C:\Windows\System32).

?? How Does It Work?

Attackers manipulate file paths in web requests, using sequences like:

../../../../../etc/passwd
        

This grants access to system-level files not intended for public exposure.

?? Real-Life Example:

If a website loads images with the URL:

https://example.com/view?file=cat.jpg
        

An attacker could request:

https://example.com/view?file=../../../../etc/passwd
        

This exposes the server’s password file.

??? Prevention Tips:

• Validate and sanitize all user inputs.
• Use whitelisting for file paths and names.
• Implement access controls to restrict access to sensitive directories.

?? 2. Cross-Site Request Forgery (CSRF)

?? What is CSRF?

CSRF tricks a victim into executing unintended actions on a website they are authenticated to. It exploits the trust a web application has in the user’s browser.

?? How Does It Work?

An attacker embeds a malicious request into a link or form and tricks the victim into clicking it. Since the victim is logged in, the website processes the request as if it came from the user.

?? Real-Life Example:

Imagine you are logged into your bank account. An attacker sends you an email with a link:

https://bank.com/transfer?amount=1000&to=attacker_account
        

Clicking the link unintentionally transfers funds to the attacker.

??? Prevention Tips:

• Use CSRF tokens to validate requests.
• Implement SameSite cookie attributes.
• Require re-authentication for sensitive actions.

?? 3. Deserialization Attack

?? What is Deserialization?

Deserialization attacks occur when untrusted data is used to reconstruct objects. Attackers exploit vulnerabilities in the deserialization process to execute malicious code or tamper with data.

?? How Does It Work?

If a web app accepts serialized objects from users, attackers can modify the serialized data to execute arbitrary code on the server.

?? Real-Life Example:

A PHP application accepting serialized data might process:

O:4:"User":2:{s:8:"username";s:5:"admin";s:6:"access";s:5:"admin";}
        

Attackers could tamper with the data to escalate privileges.

??? Prevention Tips:

• Avoid deserializing untrusted data.
• Use data integrity checks.
• Use secure deserialization libraries.

?? 4. Injection Attacks

Injection attacks exploit flaws in the handling of untrusted data by inserting malicious code into web applications. The two most common types are SQL Injection and Command Injection.

?? SQL Injection

SQL injection occurs when attackers inject malicious SQL queries into application input fields, manipulating the database.

?? How Does It Work?

By entering malicious SQL statements like:

' OR '1'='1
        

Attackers can bypass authentication or extract sensitive data.

?? Real-Life Example:

A vulnerable login form:

SELECT * FROM users WHERE username = '$user' AND password = '$pass'
        

If the attacker inputs:

' OR '1'='1'; --
        

They gain unauthorized access.

??? Prevention Tips:

• Use parameterized queries.
• Employ prepared statements.
• Use ORM frameworks to prevent direct SQL interaction.

?? Command Injection

Command injection involves injecting malicious system commands through vulnerable application inputs.

?? How Does It Work?

An attacker might enter:

; rm -rf / # 
        

into a web form, causing the server to delete files.

?? Real-Life Example:

If a web app uses:

system("ping " . $_GET['ip']);
        

An attacker could input:

127.0.0.1; rm -rf / 
        

To execute the rm -rf / command, wiping server data.

??? Prevention Tips:

• Validate input and use allowlists.
• Use escaping mechanisms.
• Run apps with limited privileges.

?? 5. Insecure Direct Object Reference (IDOR)

?? What is IDOR?

IDOR vulnerabilities occur when attackers directly access database objects or files without proper authorization.

?? How Does It Work?

If a web app uses object IDs in URLs:

https://example.com/user/1234
        

An attacker could modify the ID:

https://example.com/user/5678
        

Gaining access to another user’s data.

??? Prevention Tips:

• Enforce access controls.
• Use UUIDs instead of sequential IDs.
• Validate user authorization before returning data.

?? 6. Session Hijacking

?? What is Session Hijacking?

In session hijacking, attackers steal session tokens to impersonate legitimate users.

?? How Does It Work?

Attackers use XSS or packet sniffing to capture session cookies.

?? Real-Life Example:

An attacker captures this cookie:

sessionid=abc123
        

And uses it to log in as the victim.

??? Prevention Tips:

• Use HTTP-only and Secure flags on cookies.
• Implement session expiration.
• Use multi-factor authentication (MFA).

?? 7. File Inclusion

?? What is File Inclusion?

File inclusion vulnerabilities allow attackers to include arbitrary files in server execution, leading to RCE (Remote Code Execution).

?? How Does It Work?

Attackers exploit web applications that use file inclusion mechanisms:

include($_GET['page']);
        

By entering:

?page=../../../../etc/passwd
        

They access sensitive files.

?? Real-Life Example:

An attacker could inject:

?page=../../../../var/log/auth.log
        

To read server logs.

??? Prevention Tips:

• Use allowlists for file inclusion.
• Disable remote file execution.
• Sanitize and validate inputs.

?? Key Takeaways

1. Web applications are prone to several common attacks due to insecure coding practices.
2. Implementing proper input validation, access controls, and authentication mechanisms is key to mitigating these risks.
3. Regular security audits, code reviews, and penetration testing are essential for robust protection.