Client → Multipart parser → Size limiter → MIME validator → Malware scanner → Storage (local/remote) → Job queue Instead of loading the entire file into RAM, GunnerProject uses io.TeeReader (Go) or streaming multipart (Python/Node) to write chunks directly to disk or S3.
| Check | Implementation | |-------|----------------| | File extension whitelist | Only .pdf, .docx, .jpg, .png allowed | | MIME verification | Reject if mime.TypeByExtension ≠ detected MIME | | AV scanning | Integrate ClamAV daemon or YARA rules | | Filename sanitization | Replace all non-alphanumeric chars with _ | | Directory traversal prevention | filepath.Base(filename) + absolute root path | fileupload gunnerproject
I have written it to be , suitable for a developer documentation or a research blog. Building a Resilient File Upload Module for GunnerProject: Tactics, Validation, and Evasion By GunnerProject Dev Team Published: April 14, 2026 Introduction File upload functionality is the most commonly exploited attack surface in modern web applications. For GunnerProject, whether you are building a red-team exfiltration tool, a secure file drop server, or a collaborative platform, implementing a robust upload handler is critical. Client → Multipart parser → Size limiter →
<binary data> ------WebKitFormBoundary-- For GunnerProject, whether you are building a red-team