Offensive security assessments
Open File Upload
This page covers the specific angle of upload functionality and uploaded files being exposed without proper access control. For full exploitation of upload validation flaws (web shells, extension and content-type bypasses), see the sibling Unrestricted File Upload page.
Related topics
| Topic | Summary |
|---|---|
| Application Logic Flaws | Application Logic Flaws occur when a web application's normal logic or workflow can be manipulated, allowing attackers to bypass security measures or misuse functionality in unexpected ways. |
| Arbitrary Cookie Flags | Cookies that hold session or sensitive data are set without the proper security flags (Secure, HttpOnly, SameSite). This lets cookies travel over cleartext, be read by JavaScript, or be sent on cross-site requests, enabling theft and CSRF. |
| Back Button Attack | After a user logs out (or on a shared device), pressing the browser Back button or reopening cached pages reveals sensitive data or restores an authenticated view. This happens when the server lets responses be cached and does not fully invalidate the session. |
| Broken Authentication | Flaws in how an application confirms a user's identity, letting attackers compromise passwords, tokens, or sessions and assume other users' identities. It is one of the highest-impact web risks (OWASP Top 10: Identification and Authentication Failures). |
| Brute Force Attack | An attacker systematically tries many credentials, tokens, or values until one works. It succeeds when an endpoint lacks rate limiting, lockout, or sufficient secret entropy. |
| Captcha Bypass | A CAPTCHA is meant to block automated requests, but flawed implementation lets attackers skip or solve it programmatically. Bypassing it re-enables brute force, spam, and other automation the control was meant to stop. |