file-storage-processing

Secure file uploads require streaming transfers, MIME allowlisting, magic-byte verification, and malware scanning with quarantine-before-availability to prevent infected content from becoming referenceable. This approach also enforces archive-structure caps to stop decompression abuse and zip-slip attacks.

Signed URLs for object storage downloads must be scoped with tenant-scoped authorization and strict download headers, including attachment disposition and nosniff directives, to prevent cross-tenant data exposure and ensure tenant-safe caching.

Magic-byte verification validates user-generated content uploads by inspecting the file's underlying binary signature rather than trusting the declared MIME type, ensuring the actual file structure matches expectations before accepting the transfer.

Sandboxed media processing applies hardened processing policies to generate safe derivatives while stripping metadata like EXIF and GPS data, ensuring transformed media is safe for delivery and preventing inadvertent exposure of sensitive location information.

Object storage lifecycle cleanup manages retention and automatically handles quarantine, deletion, and cleanup for failed transforms and expired artifacts, creating observability-ready state transitions from uploading through deletion to control runaway storage costs.

Relying solely on declared MIME type for content validation is unsafe because clients can spoof headers, requiring magic-byte enforcement to verify the actual binary structure and prevent malicious file masquerading during object storage intake.