# True user isolation, explained

> Why 0700 permissions and dedicated PHP-FPM pools mean one compromised site can't take the whole server with it.

Source: https://www.corepanel.net/blog/true-user-isolation
Author: CorePanel Team
Published: 2026-07-08
Tags: security, architecture
From the CorePanel blog — https://www.corepanel.net/blog

---

"Shared hosting" usually means shared *risk*: dozens of sites running as the same web
user, in world-readable directories, behind one PHP process pool. Break into one, and
you can often read — or write — the others. CorePanel is built so that doesn't happen.

## A separate Linux user per account

Every account is a real system user with its own home directory at `0700`, with files
written `0600`. There is no shared web user, and no group- or world-readable path between
accounts. The operating system's own permission model does the enforcing — not a
convention we hope everyone follows.

```bash
drwx------ alice alice  /home/alice
drwx------ bravo bravo  /home/bravo
```

`alice` cannot list, read, or write anything under `bravo`, and vice versa. The web server
serves each site by reading its files **as that account's own user**, so the private
`0700`/`0600` permissions never need to be loosened for the web to work.

## A dedicated PHP-FPM pool per user

Each account gets its own PHP-FPM pool, running as that account's system user. A PHP
exploit in one site executes with that user's permissions and nothing more — it can't
reach into another account's files or processes.

This is the difference between "one site got hacked" and "the whole server got hacked."

## Why it matters for you

If you host clients, isolation is the line between an incident and a catastrophe. If you
host your own projects, it means a vulnerable plugin on a side project can't compromise
your main site.

True isolation ships in **every** edition, including [Personal](https://www.corepanel.net/pricing) — it's a
foundation, not an upsell.