Security Architecture & Penetration Testing
Our zero-upload architecture eliminates the attack surfaces that traditional online file tools expose. Here's how.
Attack Surface Comparison
Traditional online PDF tools (iLovePDF, SmallPDF, Adobe Acrobat Online) accept file uploads to their servers, creating attack surfaces for file-based exploits, data breaches, and supply chain attacks. MiOffice's client-side architecture eliminates these surfaces entirely.
| Attack Surface | Traditional Tools | MiOffice |
|---|---|---|
| File Upload to Server | Critical — malicious file parsing, path traversal, arbitrary code execution | Eliminated — no file upload endpoint exists. Files never leave the browser. |
| Server-Side File Processing | Critical — command injection via filenames, SSRF via embedded URLs, memory corruption | Eliminated — all file processing runs in client-side WebAssembly sandbox. |
| Data at Rest | High — database breach exposes all processed documents | Eliminated — no file data stored on any server. No database of user files exists. |
| Data in Transit | High — MITM on file upload/download, TLS stripping | Eliminated — files never transit network. Only static page assets are served over TLS 1.3 + HSTS. |
| User Authentication | High — credential stuffing, session hijacking, privilege escalation | Eliminated — no user accounts, no passwords, no sessions, no cookies tied to file operations. |
| API Endpoints | High — injection, broken access control, rate limiting bypass | Minimal — only analytics beacon endpoint. No file data in API requests. |
| Third-Party Dependencies (Server) | Medium — supply chain attacks on server libraries | Eliminated — no server-side file processing libraries. WASM modules are client-side and versioned. |
Defense-in-Depth Layers
Transport Security
TLS 1.3 with strong cipher suites. HSTS with preload (max-age=31536000, includeSubDomains). Certificate transparency monitoring.
WebAssembly Sandbox
All file processing runs in WASM linear memory — isolated from the JavaScript heap and DOM. No access to filesystem, network, or system calls.
Content Security
X-Content-Type-Options: nosniff. X-Frame-Options: DENY. Referrer-Policy: strict-origin-when-cross-origin. COEP: credentialless for SharedArrayBuffer isolation.
Memory Safety
WASM provides bounds-checked memory access. No buffer overflows possible. Memory is garbage-collected when the processing tab closes.
Subresource Integrity
WASM modules and critical scripts loaded with integrity verification. Prevents CDN compromise from injecting malicious code.
Network Isolation
File processing generates zero network requests. Verifiable via browser DevTools Network tab during any file operation.
Verify It Yourself
Our security claims are independently verifiable. You don't have to trust us — you can prove it.
Browser DevTools
Open Network tab → process any file → observe zero outbound data transfers. The file never leaves your browser.
SSL Labs Test
Run ssllabs.com/ssltest against mioffice.ai. We score A+ with TLS 1.3 and strong configuration.
Security Headers Scan
Run securityheaders.com against mioffice.ai. We score A with all recommended headers (CSP intentionally omitted for WASM compatibility).
Mozilla Observatory
Run observatory.mozilla.org against mioffice.ai. B+ score with detailed analysis of our HTTP security configuration.
Found a vulnerability?
We welcome responsible disclosure from security researchers.