Training October 11, 2025

Understanding OWASP Top 10: Web, Mobile, and API Security Risks

The OWASP Top 10 is a widely recognized list of the most critical security risks for applications. It helps developers, testers, and security professionals understand common vulnerabilities and how to protect against them. OWASP maintains separate Top 10 lists for Web Applications, Mobile Applications, and APIs, each focusing on the specific threats in these areas.

OWASP Top 10 for Web Applications

The web is a major target for attackers because of its wide use. The OWASP Web Top 10 highlights common issues such as:

Injection: Malicious code is injected into an application, like SQL injection, leading to data breaches.
Broken Authentication: Weak authentication allows attackers to impersonate users.
Sensitive Data Exposure: Inadequate protection of data can expose personal or financial information.
XML External Entities (XXE): Vulnerabilities in XML processors that can lead to data retrieval or denial of service.
Broken Access Control: Users can access data or functions beyond their permissions.
Security Misconfiguration: Bad configuration of web servers, databases, or apps.
Cross-Site Scripting (XSS): Injection of malicious scripts into webpages viewed by other users.
Insecure Deserialization: Executing malicious objects when they are deserialized.
Using Components with Known Vulnerabilities: Public libraries or frameworks susceptible to exploits.
Insufficient Logging and Monitoring: Failure to detect attacks or respond timely.

OWASP Top 10 for Mobile Applications

Mobile apps have unique risks due to device constraints and user behavior. Key mobile risks include:

Improper Platform Usage: Misusing platform features like Android intents or iOS Keychain.
Insecure Data Storage: Sensitive data saved insecurely on the device.
Insecure Communication: Data sent over unencrypted channels.
Insecure Authentication: Weak protections for user login or credentials.
Insufficient Cryptography: Poor encryption or flawed implementation.
Insecure Authorization: Incorrectly implemented user permissions.
Client Code Quality: Bugs or flaws in the app code.
Code Tampering: Modifying the app binary to bypass security.
Reverse Engineering: Attackers analyzing the app for vulnerabilities.
Extraneous Functionality: Hidden features like backdoors or debugging.

OWASP Top 10 for APIs

APIs connect different services, so security holes can cause wide damage. The main API security risks are:

Broken Object Level Authorization: Users access data objects they shouldn’t.
Broken User Authentication: Poor authentication mechanisms for API users.
Excessive Data Exposure: APIs return more data than necessary.
Lack of Resources and Rate Limiting: Absence of limits allows denial-of-service attacks.
Broken Function Level Authorization: Accessing functions beyond allowed roles.
Mass Assignment: Unintended object properties updated by clients.
Security Misconfiguration: Exposing sensitive information through default settings.
Injection: Like web apps, injections affect APIs if inputs aren’t sanitized.
Improper Assets Management: Using outdated or forgotten API versions.
Insufficient Logging & Monitoring: Makes it difficult to detect attacks.