akashrpatil Business Logic Vulnerabilities — 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: Excessive client-side trust 🟢 APPRENTICE
Intercept purchase request, change price=100 to price=1. Server trusts client-sent price.
Lab 2: High-level logic vulnerability 🟡 PRACTITIONER
Set quantity=-1 → negative total. Or quantity so high it wraps around (integer overflow) → price becomes negative.
Lab 3: Inconsistent security controls 🟡 PRACTITIONER
Register with attacker email, then change email to @dontwannacry.com to get admin access.
Lab 4: Flawed business rules 🟡 PRACTITIONER
Alternate between two coupon codes: NEWCUST5 → SIGNUP30 → NEWCUST5 → SIGNUP30. System only blocks consecutive duplicates.
Lab 5: Low-level logic flaw 🟡 PRACTITIONER
Add quantity until price integer overflows past MAX_INT → wraps to negative. Add enough to bring total to small positive number.
Lab 6: Exceptional input handling 🟡 PRACTITIONER
255+ char email: attacker@verylongstring...dontwannacry.com — email truncated to 255 chars, domain becomes @dontwannacry.com.
Lab 7: Weak isolation on dual-use endpoint 🟡 PRACTITIONER
Password change endpoint: remove current-password parameter entirely. Server doesn't require it for admin functionality.
Lab 8: Insufficient workflow validation 🟡 PRACTITIONER
After adding items, skip to order confirmation: POST /cart/order-confirmation without going through payment.
Lab 9: Auth bypass flawed state machine 🟡 PRACTITIONER
Drop the role-selection request after login → default role = admin.
Lab 10: Infinite money 🟡 PRACTITIONER
Buy gift card with discount code → redeem gift card → net positive → repeat with Burp macro/session handling rules.
Lab 11: Auth bypass encryption oracle 🔴 EXPERT
Exploit padding oracle or encryption/decryption endpoint to forge admin session cookie.
Lab 12: Email parsing discrepancies 🔴 EXPERT
attacker@dontwannacry.com%00@normal.com
Backend processes first email (before null byte), frontend validates second.
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