Web Application Penetration Test for a Growing E-Commerce Platform
A fast-growing subscription e-commerce platform engaged us prior to a major platform relaunch to conduct a full web application penetration test. We discovered a critical authentication bypass via weak token entropy, a race condition enabling double spending in the rewards system, and multiple business logic flaws while the platform served over 80,000 active subscribers.
Confidential engagement. NDA available upon request.
71%
Vulnerability Reduction
0
Critical Remaining
0
High Remaining
80K
Subscribers Protected
About the Client
Industry
E-Commerce
Company Size
30 to 50 employees, growth stage
Background
A subscription-based e-commerce platform with over 80,000 active subscribers offering curated product boxes. The client was preparing for a major platform relaunch and required a thorough security assessment to ensure subscriber data and payment integrity were protected ahead of the go-live date.
Security Challenges Identified
Predictable Password Reset Tokens Enabling Account Takeover
Password reset tokens were generated using weak randomness, making them predictable and allowing complete account takeover of any user account without their knowledge or interaction.
Race Condition in Rewards Redemption Flow
Concurrent redemption requests could be submitted before balance validation completed, allowing rewards points to be spent multiple times. This created direct financial fraud risk.
Stored XSS via Unsanitized Product Review Fields
Product review submission fields accepted and stored arbitrary script content that was later executed in the administrative panel context, creating a persistent XSS attack vector.
No Account Lockout or Brute-Force Protection
The login endpoint accepted unlimited authentication attempts with no lockout, CAPTCHA, or rate limiting, enabling automated credential stuffing against the full subscriber base.
The Mission
Discover and remediate all authentication, authorization, and business logic vulnerabilities across the subscription platform to protect 80,000+ subscribers and ensure a clean security posture ahead of the platform relaunch date.
How We Approached It
01. Reconnaissance & Asset Mapping
Week 1- Nmap service discovery and technology fingerprinting
- Nikto web server scanning
- Manual application crawl and endpoint enumeration
- Authentication and session management flow analysis
02. Automated Web Application Scanning
Week 1- OWASP ZAP active scan against all identified endpoints
- SQLMap injection testing across parameter inputs
- Burp Suite passive analysis during manual browsing
- Firefox DevTools analysis of client-side JavaScript logic
03. Manual Authentication & Authorization Testing
Week 2- Password reset token entropy analysis and predictability testing
- Session token analysis and fixation testing
- Horizontal and vertical privilege escalation testing
- IDOR testing across user-owned resources
04. Business Logic & Race Condition Testing
Week 2 to 3- Concurrent request testing on rewards redemption endpoints
- Coupon code enumeration and predictability analysis
- Subscription bypass and pricing manipulation testing
- Payment workflow edge case and abuse scenario testing
05. Reporting, Remediation & Re-Test
Week 3 to 4- Prioritized technical findings report with CVSS scores
- Developer remediation workshop sessions
- Post-fix re-testing of all critical and high findings
- Pre-launch security sign-off confirmation
Vulnerabilities Discovered
1
CRITICAL
3
HIGH
2
MEDIUM
1
LOW
Authentication Bypass via Password Reset Flaw
Password reset tokens were predictable due to weak randomness implementation, allowing account takeover without user interaction.
Password reset tokens were predictable due to weak randomness implementation, allowing account takeover without user interaction.
Race Condition in Rewards Redemption
Concurrent redemption requests could be submitted before balance validation completed, allowing points to be spent multiple times.
Concurrent redemption requests could be submitted before balance validation completed, allowing points to be spent multiple times.
Stored Cross-Site Scripting (XSS)
Product review submission fields accepted and stored unsanitized script content, executable in admin panel context.
Product review submission fields accepted and stored unsanitized script content, executable in admin panel context.
Coupon Code Enumeration
Discount codes followed a predictable sequential format, allowing bulk enumeration and unauthorized use.
Discount codes followed a predictable sequential format, allowing bulk enumeration and unauthorized use.
Verbose Error Messages
Database error messages disclosed internal table names and query structure on invalid input.
Database error messages disclosed internal table names and query structure on invalid input.
Missing Account Lockout
Login endpoint had no lockout or CAPTCHA mechanism, enabling credential stuffing attacks.
Login endpoint had no lockout or CAPTCHA mechanism, enabling credential stuffing attacks.
Outdated JavaScript Libraries
Several front-end libraries with known low-severity CVEs were identified in use.
Several front-end libraries with known low-severity CVEs were identified in use.
How We Fixed It
Password Reset Hardening
Replaced predictable token generation with cryptographically secure random token generation using 256-bit entropy, with 15-minute expiration and single-use enforcement.
Race Condition Fix
Implemented database-level transaction locking on rewards redemption operations to prevent concurrent exploitation.
XSS Remediation
Applied output encoding and Content Security Policy; implemented HTML sanitization on input.
Coupon System Redesign
Migrated coupon codes to randomly generated alphanumeric format with server-side usage validation.
Error Handling
Implemented generic error responses for user-facing error states, with detailed logging preserved server-side only.
Account Lockout
Deployed progressive lockout with CAPTCHA challenge after repeated failed login attempts within a short window.
Measurable Outcomes
Re-testing confirmed all critical and high-severity vulnerabilities were fully remediated prior to the platform relaunch date.
71%
Total Vulnerability Reduction
95%
Authentication Security Score Improvement
90%
Business Logic Risk Reduction
80K
Subscribers Protected
Critical Vulnerabilities
1
0
High Vulnerabilities
3
0
Medium Vulnerabilities
2
0
Total Confirmed Vulnerabilities
7
2 (low severity)
Authentication Security
Weak token entropy
Cryptographically secure
Business Logic Abuse Risk
High
Low
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