Personally Identifiable Information (PII) is any data that can identify an individual. In security testing and bug bounty hunting, finding exposed PII is a critical high-impact discovery. This series will cover discovery, validation, and reporting across three parts.

PII is categorized by how directly it identifies a person and its sensitivity. Core categories include direct identifiers like SSN or passport numbers, and indirect identifiers that identify a person when combined with other data.

PII is also classified as sensitive or non-sensitive based on the potential harm caused by a leak. Sensitive PII, such as financial or medical records, requires strong protection. Non-sensitive PII, like public phone numbers or email addresses, typically poses a lower risk.

🔥 What Actually Qualifies as PII?

🔸 Direct Identifiers (Highest Risk)

  • National ID (SSN)
  • Passport Number
  • Full Name + Date of Birth
  • Driver's License Number

🔸 Digital Identifiers

  • Email Address
  • IP Address
  • Account Username
  • Device ID
  • Social Media Profile with identifying details

🔸 Financial Identifiers

  • Full Credit/Debit Card Number (PAN)
  • Bank Account Number

🔸 Contextual Identifiers

  • Information that, when combined (e.g., Job Title + Company + City), can identify a person.

💡 Why PII Hunting is Critical for Security & Bounty

  • Legal & Compliance: Exposing PII violates major regulations like GDPR, CCPA, and HIPAA, leading to massive fines.
  • High-Impact Findings: A single leak can affect thousands of users, making it a high-severity bug bounty issue.
  • Real-World Harm: Exposed data fuels identity theft, financial fraud, and phishing attacks.

🛠 Part 1: The Reconnaissance & Initial Discovery Phase

Goal: Identify data entry points and potential leak sources.

1️⃣ Target Surface Mapping

  • Map all subdomains: assetfinder, subfinder, amass
  • Identify technologies: wappalyzer, builtwith
  • Find parameters: arjun, paramspider

2️⃣ Google Dorking for Obvious Leaks

site:example.com filetype:csv | filetype:xlsx | filetype:pdf
site:example.com "confidential" | "internal" | "employee list"
intitle:"index of" "backup" site:example.com

3️⃣ Basic Fuzzing for Common Files

Look for common backup or configuration files that may contain sensitive data:

ffuf -w ~/SecLists/Discovery/Web-Content/common.txt -u https://target.com/FUZZ -e .bak,.old,.txt,.sql,.tar.gz

Other important tools: subfinder, amass, httpx, gobuster

🔔 What's Next?

Follow @cybersecplayground for Part 2: Deep-Dive PII Hunting Techniques.

✅ Like & Share if you're ready to hunt for data leaks! 🔍

⚠️ Pro Tip: Always check /robots.txt and /.git/ for clues about hidden directories containing data!

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#PII #Reconnaissance #BugBounty #OSINT #CyberSecurity #DataLeak #InfoSec