OK, let's review the security.

Here are variations with different severity levels.

Purposefully putting medium on top to make sure the severity levels are sorted correctly.

## Medium Severity

<dyad-security-finding title="Unvalidated File Upload Extensions" level="medium">
**What**: The file upload endpoint accepts any file type without validating extensions or content, only checking file size

**Risk**: An attacker could upload malicious files (e.g., .exe, .php) that might be executed if the server is misconfigured, or upload extremely large files to consume storage space

**Potential Solutions**: 
1. Implement a whitelist of allowed file extensions (e.g., `.jpg`, `.png`, `.pdf`)
2. Validate file content type using magic numbers, not just the extension
3. Store uploaded files outside the web root with random filenames
4. Implement virus scanning for uploaded files using ClamAV or similar

**Relevant Files**: `src/api/upload.ts`

</dyad-security-finding>

<dyad-security-finding title="Missing CSRF Protection on State-Changing Operations" level="medium">
**What**: POST, PUT, and DELETE endpoints don't implement CSRF tokens, making them vulnerable to cross-site request forgery attacks

**Risk**: An attacker could trick authenticated users into unknowingly performing actions like changing their email, making purchases, or deleting data by visiting a malicious website

**Potential Solutions**: 
1. Implement CSRF tokens using a library like `csurf` for Express
2. Set `SameSite=Strict` or `SameSite=Lax` on session cookies
3. Verify the `Origin` or `Referer` header for sensitive operations
4. For API-only applications, consider using custom headers that browsers can't set cross-origin

**Relevant Files**: `src/middleware/auth.ts`, `src/api/*.ts`

</dyad-security-finding>

## Critical Severity

<dyad-security-finding title="SQL Injection in User Lookup" level="critical">
**What**: User input flows directly into database queries without validation, allowing attackers to execute arbitrary SQL commands

**Risk**: An attacker could steal all customer data, delete your entire database, or take over admin accounts by manipulating the URL

**Potential Solutions**: 
1. Use parameterized queries: `db.query('SELECT * FROM users WHERE id = ?', [userId])`
2. Add input validation to ensure `userId` is a number
3. Implement an ORM like Prisma or TypeORM that prevents SQL injection by default

**Relevant Files**: `src/api/users.ts`

</dyad-security-finding>

<dyad-security-finding title="Hardcoded AWS Credentials in Source Code" level="critical">
**What**: AWS access keys are stored directly in the codebase and committed to version control, exposing full cloud infrastructure access

**Risk**: Anyone with repository access (including former employees or compromised accounts) could spin up expensive resources, access S3 buckets with customer data, or destroy production infrastructure

**Potential Solutions**: 
1. Immediately rotate the exposed credentials in AWS IAM
2. Use environment variables and add `.env` to `.gitignore`
3. Implement AWS Secrets Manager or similar vault solution
4. Scan git history and purge the credentials using tools like `git-filter-repo`

**Relevant Files**: `src/config/aws.ts`, `src/services/s3-uploader.ts`

</dyad-security-finding>

## High Severity

<dyad-security-finding title="Missing Authentication on Admin Endpoints" level="high">
**What**: Administrative API endpoints can be accessed without authentication, relying only on URL obscurity

**Risk**: An attacker who discovers these endpoints could modify user permissions, access sensitive reports, or change system configurations without credentials

**Potential Solutions**: 
1. Add authentication middleware to all `/admin/*` routes
2. Implement role-based access control (RBAC) to verify admin permissions
3. Add audit logging for all administrative actions
4. Consider implementing rate limiting on admin endpoints

**Relevant Files**: `src/api/admin/users.ts`, `src/api/admin/settings.ts`

</dyad-security-finding>

<dyad-security-finding title="JWT Secret Using Default Value" level="high">
**What**: The application uses a hardcoded default JWT secret ("your-secret-key") for signing authentication tokens

**Risk**: Attackers can forge valid JWT tokens to impersonate any user, including administrators, granting them unauthorized access to user accounts and sensitive data

**Potential Solutions**: 
1. Generate a strong random secret: `openssl rand -base64 32`
2. Store the secret in environment variables
3. Rotate the JWT secret, which will invalidate all existing sessions
4. Consider using RS256 (asymmetric) instead of HS256 for better security

**Relevant Files**: `src/auth/jwt.ts`

</dyad-security-finding>

## Low Severity

<dyad-security-finding title="Verbose Error Messages Expose Stack Traces" level="low">
**What**: Production error responses include full stack traces and internal file paths that are sent to end users

**Risk**: Attackers can use this information to map your application structure, identify frameworks and versions, and find potential attack vectors more easily

**Potential Solutions**: 
1. Configure different error handlers for production vs development
2. Log detailed errors server-side but send generic messages to clients
3. Use an error handling middleware: `if (process.env.NODE_ENV === 'production') { /* hide details */ }`
4. Implement centralized error logging with tools like Sentry

**Relevant Files**: `src/middleware/error-handler.ts`

</dyad-security-finding>

<dyad-security-finding title="Missing Security Headers" level="low">
**What**: The application doesn't set recommended security headers like `X-Frame-Options`, `X-Content-Type-Options`, and `Strict-Transport-Security`

**Risk**: Users may be vulnerable to clickjacking attacks, MIME-type sniffing, or man-in-the-middle attacks, though exploitation requires specific conditions

**Potential Solutions**: 
1. Use Helmet.js middleware: `app.use(helmet())`
2. Configure headers manually in your web server (nginx/Apache) or application
3. Set `Content-Security-Policy` to prevent XSS attacks
4. Enable HSTS to enforce HTTPS connections

**Relevant Files**: `src/app.ts`, `nginx.conf`

</dyad-security-finding>