100 Web App Exploits for Cybersecurity: Threats & Defenses Every Bug Bounty Hunter Should Know in 2025 Cybersecurity
As web applications continue to evolve, so do the threats that security researchers and bug bounty hunters must tackle. Understanding the top vulnerabilities is essential for identifying security flaws and safeguarding digital assets. Below is a comprehensive guide covering the Top 100 Web App Exploits For cybersecurity that every bug bounty hunter should be familiar with in 2025.
1. Cross-Site Scripting (XSS)
XSS attacks allow attackers to inject malicious scripts into web pages viewed by users. This can lead to data theft, session hijacking, or even full account takeovers.
Reflected XSS – Occurs when malicious input is reflected immediately in the response.
Stored XSS – The script is stored in the database and executed when a user loads the page.
DOM-Based XSS – The attack occurs due to improper handling of user input in the DOM.
Mutation XSS – Malicious payloads mutate when processed by the browser.
Blind XSS – Exploits situations where input is processed asynchronously.
Filter Bypasses – Techniques to bypass security filters and execute XSS attacks.
🔐 2. SQL Injection (SQLi)
A powerful attack technique used to manipulate SQL queries by injecting malicious SQL statements.
Union-based SQLi – Retrieves additional data by manipulating UNION queries.
Error-based SQLi – Exploits errors to extract information from the database.
Blind SQLi – The attacker infers database information through indirect responses.
💥 3. Cross-Site Request Forgery (CSRF)
Tricks users into making unwanted requests on authenticated websites, potentially leading to data manipulation or unauthorized actions.
🔍 4. Insecure Direct Object References (IDOR)
A vulnerability that occurs when applications expose direct access to internal objects (e.g., user IDs, files) without proper authorization.
🛠️ 5. Remote Code Execution (RCE)
Allows attackers to execute arbitrary code on a server, leading to full system compromise.
🔑 6. Server-Side Request Forgery (SSRF)
Exploits a server's ability to make HTTP requests, allowing attackers to access internal services or retrieve sensitive data.
⚙️ 7. Local File Inclusion (LFI)
Allows attackers to include files from the local server, potentially leading to information disclosure or code execution.
📄 8. Remote File Inclusion (RFI)
Enables the inclusion of remote malicious scripts into a web application, leading to compromise.
⚠️ 9. Command Injection
A vulnerability that allows attackers to execute system commands on the server.
🔐 10. Authentication Bypass
Occurs when authentication mechanisms are improperly implemented, leading to unauthorized access.
JWT vulnerabilities – Weak implementation of JSON Web Tokens can be exploited.
Session Fixation – Attackers force users to use known session IDs.
Cookie Hijacking – Attackers steal session cookies to impersonate users.
🕵️♂️ 11. Clickjacking
Tricks users into clicking on something different than they intended by overlaying deceptive UI elements.
🔗 12. Open Redirects
A vulnerability that allows attackers to redirect users to malicious sites.
🧳 13. Path Traversal
Allows access to restricted directories and files by manipulating file paths.
🔄 14. Improper Authorization
Occurs when access controls are not properly enforced, leading to data exposure.
🔓 15. Privilege Escalation
Attackers exploit vulnerabilities to gain higher access levels within a system.
💻 16. XML External Entity (XXE) Injection
Exploits XML parsers to access internal files and execute system commands.
🔎 17. Mass Assignment Vulnerabilities
Occurs when attackers manipulate object properties that were not intended to be modified.
💣 18. HTTP Response Splitting
Allows attackers to manipulate HTTP responses, leading to cache poisoning or XSS.
⛔ 19. Broken Access Control
A broad category of vulnerabilities that allow attackers to bypass security restrictions.
🔑 20. Insufficient Logging & Monitoring
Poor logging practices make it difficult to detect and respond to security incidents.
📡 21. DNS Poisoning
An attack that corrupts the DNS resolution process to redirect users to malicious sites.
💥 22. Directory Traversal
Exploits improper file path handling to access restricted files.
⚔️ 23. Unvalidated Redirects and Forwards
Allow attackers to redirect users to malicious sites or manipulate application logic.
🔒 24. Race Conditions
Occurs when concurrent processes are improperly handled, leading to security flaws.
🛡️ 25. Security Misconfiguration
Exploits weaknesses in default settings, outdated components, or unnecessary features.
💥 26. Session Hijacking
An attack where session tokens are stolen to gain unauthorized access.
🕶️ 27. Content Security Policy (CSP) Misconfigurations
Improper CSP implementation can allow XSS attacks to succeed.
🔍 28. XML Injection
Manipulates XML data to alter application behavior or leak sensitive information.
🚀 29. Buffer Overflow Vulnerabilities
Attackers exploit improper memory handling to execute malicious code.
🔑 30. Insecure Deserialization
Allows attackers to execute arbitrary code by manipulating serialized data.
🔌 31. Insecure Communication Channels
Lack of encryption (e.g., HTTP instead of HTTPS) exposes data to attackers.
⚡ 32. Cross-Site WebSocket Hijacking
Exploits weak WebSocket implementations to intercept user communications.
🔒 33. Clickjacking via iFrames
Similar to clickjacking, but executed through embedded iframes.
⚙️ 34. Unauthorized API Access
Weak API authentication can allow attackers to access sensitive endpoints.
💻 35. Broken Cryptography
Use of outdated or weak cryptographic algorithms can be exploited.
🔌 36. Weak Password Storage
Poor password hashing methods (e.g., MD5, SHA1) make credential cracking easier.
💥 37. Subdomain Takeover
Occurs when expired or misconfigured subdomains allow attackers to take control.
🔎 38. Web Cache Poisoning
Attackers manipulate cached responses to serve malicious content.
🔒 39. DNS Rebinding Attacks
Exploits browsers to bypass same-origin policies and attack internal networks.
⚙️ 40. Arbitrary File Upload
Poor file validation allows attackers to upload malicious scripts.
⚠️ 41. Insufficient Input Validation
Failure to properly sanitize user input leads to a variety of attacks.
🛠️ 42. Blind XSS
A form of stored XSS that executes at a later time, often affecting administrators.
📡 43. Google Hacking (GHDB)
Using search engine queries to discover vulnerabilities and exposed data.
💡 44. Exposed Sensitive Data
Improper handling of sensitive data can lead to information disclosure.
This is just the start! Stay tuned for the full Top 100 Web App Exploits to sharpen your bug bounty skills in 2025! Master these techniques to improve web security and uncover vulnerabilities effectively.