Understanding reverse shells
Shell Game
Firewalls block shell access from outside the network. But what if the shell is launched from the inside?
Recently, I've thoroughly enjoyed brushing up my offensive security skills. I've worked in the defensive security field for longer than I care to remember, and gaining more insight into how attackers perceive the world has really opened my eyes. My background is two-and-half decades of Linux and securing containers over the last seven years or so. An area that always piques my interest is Linux-based local privilege escalation. Once you have found a way of gaining access to a machine, the Holy Grail is elevating your privileges to the root user so you have full control.
Sometimes achieving root can take a little time. As an attacker, it is important to be able to return at a later date if you haven't achieved root user privileges yet or you want to monitor changeable data on a machine. Penetration testers and attackers would call this ongoing access persistence, which is the ability to gain a foothold and then maintain access; you might also call it creating a backdoor.
Attackers have a multitude of ways for ensuring that, if a machine reboots or some other event occurs, a backdoor is re-established automatically. This article looks at reverse shells and provides some examples of how to achieve persistence once you have gained access to a Linux machine. It should go without saying that you should use the following information for testing, practicing, and improving your knowledge and not for some nefarious purpose.
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
The Bullet-Proof KDE Software Initiative Is Coming
KDE, Techpaladin, and Kubuntu Focus have announced a new initiative that will provide at least three years of support for KDE Plasma 6.6 LTS and related software.
-
Linux Mint Shares a Possible Kernel Cleanup Solution
For those on Linux Mint who like to keep multiple kernels around but don't want them to take up too much space, you might be getting a new automated tool.
-
CachyOS Gets an Update
CachyOS August 2026 release is now available with the latest version of KDE, some new features, and plenty of improvements.
-
The Linux Kernel Dev Staging Area Now Rejects AI-Generated Patches
Unless a kernel patch is a valid security fix, it will be rejected if it was created using AI.
-
Linux Surpasses Double-Digit Market Share
According to two sources, the Linux operating system has hit a major milestone in market share that naysayers thought would never happen.
-
AI Helped Develop a Linux Exploit
A use-after-free race exploit was discovered and exploited on CentOS Stream 9.
-
Yet Another Linux Kernel Vulnerability Discovered
Affecting millions of systems, a kernel flaw discovered by Qualys could allow users to gain root privileges.
-
Ubuntu 26.10 to Include Ubuntu Certified Hardware Check
If you've ever wondered if your laptop or PC is officially certified to run Ubuntu, that curiosity will soon be met.
-
Substantial Update to IPFire Now Available
The lastest version of IPFire features a fundamental change to how the system handles DNS.
-
Gnome Working on Test Center App to Make Testing Easier
It's now possible to test experimental features on the Gnome desktop without worrying that you'll break things.