File Permissions and OS Hardening for Clockspring

Clockspring follows a simple, predictable Linux service model. Most security questions come from confusing installation requirements with runtime permissions.

This article explains:

• who owns Clockspring files

• when root is required and when it is not

• what OS-level controls security teams should enforce

Installation vs Runtime Permissions

Installation (root required)

Root access is required for standard system-level tasks, including:

• installing RPM packages

• creating the clockspring service user

• installing systemd service files

• setting initial ownership and permissions

• registering paths and dependencies

This is normal for RPM-based software.

Runtime (root not required)

Once installed:

• the Clockspring service runs as the clockspring user

• no ongoing root access is required

• all application files and directories are owned by clockspring

After installation, security teams can restrict root access without impacting Clockspring operation.

File Ownership Model

All Clockspring runtime files are owned by a single OS user:

clockspring

This includes:

• content repositories

• FlowFile repositories

• provenance repositories

• logs

• configuration files

• working directories

Clockspring does not require shared ownership, mixed users, or elevated privileges to function.

Why Clockspring Runs as a Non-Root User

Running as root is unnecessary and increases risk.

Clockspring does not need root because it:

• does not bind to privileged ports

• does not modify kernel or network settings at runtime

• does not install packages while running

• does not require raw device access

Using a dedicated service user:

• limits blast radius

• aligns with least-privilege principles

• simplifies audits and reviews

What the clockspring User Should Be Able to Do

The clockspring user should:

• read and write its own directories

• read configuration files it owns

• write logs and repository data

• execute Clockspring binaries

It should not need:

• sudo access

• write access to system directories

• access to other users’ files

• permission to modify OS or network settings

OS-Level Controls to Enforce

File Permissions

• Ensure Clockspring directories are owned by clockspring

• Avoid group or world write permissions

• Restrict read access to configuration files that reference secrets

This prevents lateral access from other users on the host.

User Access

• Limit who can log in as or switch to the clockspring user

• Avoid shared credentials

• Audit access to the service account

Anyone with access to the clockspring user can read Clockspring data.

Disk and Filesystem Controls

• Use encrypted disks or volumes

• Apply appropriate mount options

• Monitor disk usage to avoid forced cleanup scenarios

Disk protection complements TLS and mTLS. It does not replace them.

Process Isolation

• Run Clockspring under its own service account

• Do not run unrelated services as clockspring

• Apply OS hardening consistently across environments

Shared users mean shared risk.

Common Misunderstandings

• “Clockspring must run as root” → false

• “Root is needed after installation” → false

• “File permissions are enforced by the application” → false

Clockspring relies on the OS to enforce file permissions correctly.

How This Fits with Other Security Controls

OS hardening works alongside:

• TLS and mTLS for data in motion

• disk encryption for data at rest

• firewall and network controls

• audit logging and provenance

Security is layered. File permissions are one of those layers.

Summary

Clockspring uses a standard Linux security model:

• root is required for installation

• runtime operates as the clockspring user

• all runtime files are owned by clockspring

• OS permissions enforce isolation and access control