Discovering and accessing unprotected pages, APIs, and administrative interfaces by enumerating URLs and bypassing authentication controls during authorized security assessments.
Instrucciones de origen · Vista previa de solo lectura
name
bypassing-authentication-with-forced-browsing
description
Discovering and accessing unprotected pages, APIs, and administrative interfaces by enumerating URLs and bypassing authentication controls during authorized security assessments.
Step 3: Test Authentication Enforcement on Discovered Endpoints
Compare responses between unauthenticated and authenticated requests.
# Test without authentication
curl -s -o /dev/null -w "%{http_code}" \
"https://target.example.com/admin/dashboard"# Test with valid session cookie
curl -s -o /dev/null -w "%{http_code}" \
-b "session=valid_session_token_here" \
"https://target.example.com/admin/dashboard"# Automated check: compare response sizes# Unauthenticated request
curl -s "https://target.example.com/admin/users" | wc -c
# Authenticated request
curl -s -b "session=valid_token" \
"https://target.example.com/admin/users" | wc -c
# If both return similar content, authentication is not enforced# Test with Burp Intruder: send a list of discovered URLs# without cookies and flag any 200 responses
Step 4: Test HTTP Method-Based Authentication Bypass
Some applications only enforce authentication for specific HTTP methods.
# Test different HTTP methods on protected endpointsfor method in GET POST PUT DELETE PATCH OPTIONS HEAD TRACE; doecho -n "$method: "
curl -s -o /dev/null -w "%{http_code}" \
-X "$method""https://target.example.com/admin/settings"done# Test HTTP method override headers
curl -s -o /dev/null -w "%{http_code}" \
-X POST \
-H "X-HTTP-Method-Override: GET" \
"https://target.example.com/admin/settings"
curl -s -o /dev/null -w "%{http_code}" \
-H "X-Original-Method: GET" \
-H "X-Rewrite-URL: /admin/settings" \
"https://target.example.com/"
Step 5: Test Path Traversal and URL Normalization Bypass
Exploit URL parsing differences to bypass path-based authentication rules.
Search for sensitive files inadvertently exposed on the web server.
# Backup file discovery
ffuf -u https://target.example.com/FUZZ \
-w /usr/share/seclists/Discovery/Web-Content/raft-medium-files.txt \
-e .bak,.old,.orig,.save,.swp,.tmp,.dist,.config,.sql,.gz,.tar,.zip \
-mc 200 -t 50 -rate 100
# Common sensitive filesfor file in .env .git/config .git/HEAD .svn/entries \
web.config wp-config.php.bak config.php.old \
database.yml .htpasswd server-status phpinfo.php \
robots.txt sitemap.xml crossdomain.xml; do
status=$(curl -s -o /dev/null -w "%{http_code}" \
"https://target.example.com/$file")
if [ "$status" != "404" ]; thenecho"FOUND ($status): $file"fidone# Git repository exposure check
curl -s "https://target.example.com/.git/HEAD"# If this returns "ref: refs/heads/main", the git repo is exposed
Key Concepts
Concept
Description
Forced Browsing
Directly accessing URLs that are not linked but exist on the server
Directory Enumeration
Brute-forcing directory and file names against a wordlist to discover hidden content
Authentication Bypass
Accessing protected resources without valid credentials due to missing access checks
Path Normalization
Exploiting differences in how web servers and application frameworks parse URL paths
Method-based Bypass
Using alternative HTTP methods (PUT, DELETE) that may not have authentication checks
Information Disclosure
Exposure of sensitive configuration files, backups, or debug interfaces
Defense in Depth
Layered security controls where authentication is enforced at multiple levels
Tools & Systems
Tool
Purpose
ffuf
Fast web fuzzer for directory, file, and parameter enumeration
Gobuster
Directory and DNS brute-forcing tool written in Go
Feroxbuster
Recursive content discovery tool with automatic recursion
DirBuster
OWASP Java-based directory brute-force tool with GUI
Burp Suite
HTTP proxy for request interception and automated scanning
SecLists
Comprehensive collection of wordlists for security testing
Common Scenarios
Scenario 1: Exposed Admin Panel
An admin panel at /admin/ is only hidden by not being linked in the navigation. Direct URL access reveals the full administrative interface without any authentication check.
Scenario 2: Unprotected API Endpoints
API endpoints at /api/v1/users and /api/v1/settings require authentication in the frontend application but the backend API does not enforce session validation, allowing unauthenticated direct access.
Scenario 3: Backup File Containing Credentials
A developer left config.php.bak on the production server. This backup file contains database credentials in plaintext, discovered through extension-based enumeration.
Scenario 4: Spring Boot Actuator Exposure
The /actuator/env endpoint is exposed without authentication, revealing environment variables including database connection strings, API keys, and secrets.
Output Format
## Forced Browsing / Authentication Bypass Finding
**Vulnerability**: Missing Authentication on Administrative Interface
**Severity**: Critical (CVSS 9.1)
**Location**: /admin/dashboard (GET, no authentication required)
**OWASP Category**: A01:2021 - Broken Access Control
### Discovered Unprotected Resources
| Path | Status | Auth Required | Content |
|------|--------|---------------|---------|
| /admin/dashboard | 200 | No | Full admin panel |
| /admin/users | 200 | No | User management |
| /actuator/env | 200 | No | Environment variables |
| /config.php.bak | 200 | No | Database credentials |
| /.git/HEAD | 200 | No | Git repository metadata |
### Impact
- Unauthenticated access to administrative functions
- Ability to create, modify, and delete user accounts
- Exposure of database credentials and API keys
- Full source code disclosure via exposed Git repository
### Recommendation
1. Implement authentication checks at the server/middleware level for all admin routes
2. Remove backup files, debug endpoints, and version control metadata from production
3. Configure web server to deny access to sensitive file extensions (.bak, .old, .env, .git)
4. Implement IP-based access restrictions for administrative interfaces
5. Use a reverse proxy to restrict access to internal-only endpoints
