Run0 is a new privilege escalation program for Systemd-based Linux systems. Similar to sudo, it allows you to run commands as a root user and access your machine’s internals. In this article, we compare Run0 vs Sudo to help you determine the right privilege escalation tool for you.
Run0 vs Sudo: A Side by Side Comparison
| Category | Run0 | Sudo |
|---|---|---|
| Configurability | Doesn’t come with a config file. Uses command line flags to change its behavior | Comes with two config files and a lot of command line flags |
| Ease of Use | Simple and straightforward to use for most tasks | Might require some configuration before it can work properly |
| Security | Doesn’t rely on SUID and has a smaller code footprint | Relies on SUID and has a larger attack surface due to code size |
| Extensibility | Doesn’t have support for third-party plugins | Has an API for developing third-party plugins |
| Network Support | Designed to run on a single machine | Can work with computer networks using centralized access policies |
| Best For | Casual users looking for a simpler Sudo alternative | Power users looking for a reliable option that they can customize |
What is Run0 and Why Use It
Released in version 256 of Systemd, Run0 is a unique take on privilege escalation for Linux. It uses Systemd-run to create a secure and isolated environment for running programs with root privileges.
The main selling point of Run0 is that it doesn’t rely on setuid (SUID) to run root commands. This makes the program immune to privilege escalation attacks common to large SUID programs.
Another selling point of Run0 is that it offloads its authentication agent to Polkit. This program manages the policy settings of apps on your system. Not only does it centralize authentication on your machine, but it also gives you finer control over how programs and users obtain root access.
Lastly, Run0 creates a new pseudo-TTY (PTY) whenever you invoke a privileged command. This means that programs don’t inherit the current shell environment, making it easy to isolate a misbehaving process on your system.
What is Sudo and Why Use It
Sudo is one of the earliest privilege escalation programs for Linux and other UNIX-like operating systems. First developed in the 1980s, it uses the built-in UNIX users and groups system to manage root privileges for system commands.
A key selling point of sudo is that it’s an all-in-one solution for privilege escalation and permissions. With it, you only need to configure the sudoers file to manage who can be a superuser and what programs they can run as root. This makes it attractive to system admins who want a streamlined way of managing root access.
Another reason to use sudo is that it can monitor and review the history of system commands that ran on your machine across different superusers. This is useful when troubleshooting since it can point to the exact moment the system had its issue.
Lastly, sudo is easy to scale across multiple hosts with its built-in LDAP and Active Directory support. Because of that, sudo can also be a great tool for admins who manage multiple machines for teams and businesses.
Run0 vs Sudo: A Comprehensive Comparison
While Run0 and Sudo are brilliant tools for elevating user privileges, both programs took different approaches to achieve it. Below, we look at some of those differences to help you determine which one fits better for you.
Configurability
Unlike other privilege escalation programs, Run0 doesn’t use config files to change its default behavior. Instead, you customize it using a handful of built-in flags as you run it on the terminal. This lets you focus on your workflow instead of being bogged down in tweaking config files.
On the other hand, sudo provides a lot of options across its two primary config files: “/etc/sudo.conf” and “/etc/sudoers.” Both work hand-in-hand to control how sudo works on your system. For instance, you can even configure sudo to run without a password. While this can be confusing for a new user, this level of flexibility and customization allows you to craft their own custom sudo workflow.
Winner: Sudo
Ease of Use
Most Linux distros today ship Run0 and Sudo with sensible defaults, making them easy to use without any additional configuration. That said, there are still a handful of usability quirks between the two programs that can be a dealbreaker for some users.
The main quirk of Run0 stems from its reliance on Polkit for authentication. In some terminals, Run0 can show its password prompt on a different display. This can be an issue if you’re using a terminal multiplexer, such as Tmux, to manage multiple shell sessions.
Meanwhile, Sudo’s biggest quirk is that it doesn’t allow you to edit the sudoers file through a regular text editor. Instead, it asks you to use a program called Visudo, which adds integrity checks on the sudoers file. Although this makes editing the sudoers file safer, this can be unnecessarily complex for a regular user who only wants to manage root permissions.
Winner: Run0
Source Code Size
The overall size of a program’s source code is a good indicator of how complex it currently is. This is important for privilege escalation programs since code complexity could lead to potential security exploits.
One difference of Run0 compared to other privilege escalation apps is that it’s built on top of Systemd-run. Not only does this allow Run0 to take advantage of Systemd-run’s features but it also means that the program itself doesn’t contain a lot of code. As a result, Run0 is easier to audit for potential security issues in the future.
Sudo is a massive software project spanning over multiple files and programming languages. While this complexity allowed sudo to be a powerful privilege escalation app, it also means that it has a massive attack surface for potential exploits.
Winner: Run0
Source Code Age
The age of a particular software project is also a factor when looking at how reliable a privilege escalation program will be. Newer projects are often filled with more bugs and issues, while older ones tend to be more stable.
Run0 is a relatively new program added to Systemd in June 2024. Currently, you can only obtain the app on bleeding edge distros such as Arch Linux and Fedora Rawhide. Due to that, Run0 is more suited for casual and non-mission-critical work.
Sudo is one of the oldest software projects still being developed today. With over 30 years of development history, sudo is a highly mature program capable of handling different workloads. This makes it highly desirable for those looking for a stable privilege escalation program that they can rely on.
Winner: Sudo
Run0 vs Sudo: Which App Wins
At the end of the day, choosing the right privilege escalation program depends on what you’re trying to achieve with your system:
- If you’re looking for an easy-to-use and simple privilege escalation app, Run0 is a good pick. The combination of its config-less design and approach to isolating root processes makes it great for casual users looking for a no-fuss Sudo alternative.
- If you want a customizable and stable privilege escalation app, you can’t go wrong with Sudo. With its decades-long development history and wealth of features, it’s very easy to shape Sudo to your custom workflow.
Picking the right privilege escalation app for your machine is just the first step in understanding how a superuser works in Linux. Take a deep dive to the internals of your machine and explore how Su differs from Sudo.
Image credit: Gabriel Heinzer via Unsplash. All alterations and screenshots by Ramces Red.
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