Hardening a Process

Sat, 14 Nov 2026 00:00:00 +0530

I’ll use a web application that accepts profile photos as an example. When a user uploads an image, the application saves the original and starts a separate process to generate a thumbnail. The application can read and write every file in the photo directory, but the thumbnail process only needs to read that original and write its thumbnail.

Suppose someone uploads an image that exploits a bug in the decoder and gives them control of the process. If the process runs under the application’s account, they can read or overwrite other users’ photos. Running it under a separate account helps, but the process can still use any open files the application passes to it.

Kubernetes on Rohit Jha

Hardening a Process