Web applications face a wide range of attacks that target how they process data, manage users, and interact with servers. Understanding these attack types is essential for identifying vulnerabilities and predicting how attackers might exploit them. Each attack focuses on a specific weakness in the application’s logic, configuration, or input handling.

Injection Attacks

Injection attacks occur when an application accepts untrusted input and sends it to an interpreter without proper validation. Attackers craft malicious input to alter commands, extract data, or execute unauthorized actions.

Common forms include:

• SQL injection

• Command injection

• XML injection

• LDAP injection

• Template injection

These attacks often result in data extraction, authentication bypass, or full system compromise when the backend executes attacker-controlled code.

Cross-Site Scripting

Cross-site scripting targets how a web application handles user-generated content. When input is not sanitized, attackers inject scripts that run in the browser of other users.

Main variants include:

• Stored XSS

• Reflected XSS

• DOM-based XSS

XSS allows attackers to steal cookies, manipulate user sessions, alter web pages, or impersonate victims.

Cross-Site Request Forgery

Cross-site request forgery abuses the trust a website places in a logged-in user. Attackers trick the victim’s browser into performing unintended actions, such as changing passwords or transferring funds.

CSRF occurs when session tokens are reused without proper verification. It takes advantage of how browsers automatically attach cookies to requests.

Authentication Attacks

Authentication mechanisms are frequent targets. Attackers attempt to break login flows, predict tokens, or manipulate credentials.

Techniques include:

• Brute force

• Credential stuffing

• Password spraying

• OTP bypass

• Token manipulation

Weak password policies, predictable token generation, or insecure login flows enable these attacks.

Authorization Attacks

Authorization flaws allow users to access resources or perform operations outside their intended permissions. Attackers modify parameters, URLs, or request bodies to escalate privileges.

Common examples include:

• Insecure direct object references

• Broken role validation

• Forced browsing

• Parameter tampering

These flaws often lead to data exposure or unauthorized admin-level access.

Session Attacks

Sessions maintain state between the user and the server. When poorly implemented, they allow attackers to hijack or impersonate users.

Examples include:

• Session fixation

• Session hijacking

• Weak session ID entropy

• Predictable or reusable tokens

Weak session management can compromise entire accounts.

File Upload Attacks

File upload features allow attackers to upload malicious files if checks are incomplete. Uploaded files may include shells, scripts, or payloads that execute on the server.

Attackers focus on:

• Extension bypass

• MIME-type spoofing

• Path traversal

• Uploading executable code

A single insecure upload endpoint can give attackers direct access to backend systems.

Server-Side Attacks

Server-side logic is a major target. Attackers abuse backend parsing, request handling, and remote integrations.

Important categories include:

• Server-side request forgery

• Server-side template injection

• Deserialization attacks

• Path traversal

• Remote code execution

These attacks often lead to full server compromise.

Client-Side Attacks

Client-side logic flaws allow malicious interaction within the user’s browser. Attackers exploit JavaScript, browser features, and insecure application logic.

Examples include:

• Clickjacking

• DOM manipulation

• Open redirects

• HTML injection

These attacks influence users directly and often bypass server-side protections.

Business Logic Attacks

Business logic vulnerabilities arise from flawed application workflows. Attackers manipulate how the application is intended to function.

Examples include:

• Bypassing payment steps

• Reusing discount coupons

• Modifying quantities or prices

• Exploiting race conditions

These attacks are difficult to detect because they exploit design flaws rather than technical weaknesses.

Intel Dump

• Web attacks target weaknesses in input validation, authentication, authorization, and processing.

• Injection attacks exploit unsafe input handling.

• XSS allows execution of attacker scripts in victim browsers.

• CSRF forces users to perform unwanted actions.

• Authentication and authorization flaws lead to account and privilege abuse.

• Session attacks compromise user identities.

• File upload flaws enable malicious uploads and server access.

• Server-side attacks target backend logic and integrations.

• Client-side attacks exploit browser behavior and insecure scripts.

• Business logic attacks abuse flawed workflows and design.