Tag

Linux

CTF Walkthroughs, TryHackMe

TryHackMe – Skynet Walkthrough

Introduction

This was an easy Linux box that involved accessing an open SMB share containing a list of credentials that could be used to bruteforce a SquirrelMail web application, finding SMB credentials on the application to access a new share which revealed a second web application, and exploiting a remote file inclusion vulnerability in Cuppa CMS to gain remote access. Privilege escalation was possible due to a misconfigured cron job running as root and using a wildcard with the tar command.

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April 25, 2021 | by Stefano Lanaro
CTF Walkthroughs, VulnHub

VulnHub – Kioptrix 1.4 Walkthrough

Introduction

This was an easy Linux box that involved exploiting a directory traversal vulnerability in the pChart web application in order to access the rules in the Apache configuration file, which revealed a user agent change was necessary to be able to navigate to the PHPTax web application hosted on port 8080, which was affected by a remote code execution vulnerability that could be used to gain remote access to the machine. A simple kernel exploit can then be used to escalate privileges to root.

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April 24, 2021 | by Stefano Lanaro | Leave a comment
CTF Walkthroughs, Hack The Box

Hack The Box – Laboratory Walkthrough

Introduction

This was a fairly easy Linux box that involved exploiting a local file inclusion and remote code execution vulnerability in GitLab to gain remote access to the machine, obtaining administrative access to GitLab through the console to find a user’s private key and exploiting a PATH hijack vulnerability within a SUID script to escalate privileges to root.

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April 20, 2021 | by Stefano Lanaro | 1 Comment
Guides, Linux, Privilege Escalation

Linux Privilege Escalation – Exploiting Shell Sessions

Introduction

The Linux shell (or terminal) is a program that receives commands from the user, gives them to the operating system to process, and then displays the output on the screen. To make life easier when interacting with a system through a shell, terminal multiplexers can be used; these are software applications that have the ability to combine several separate pseudoterminal-based login sessions inside a single terminal display and they are particularly useful when dealing with multiple programs from a command-line interface and for creating sub-processes that will continue running even when the user is disconnected. Their main purpose is to increase productivity, by allowing users to run multiple programs within a single interface and switch between them seamlessly.

If a terminal multiplexer session is still active as a privileged user (or a different user from the current one), a low-privileged user could be able to attach to it to elevate its access to the user the multiplexer session is running as.

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April 19, 2021 | by Stefano Lanaro | Leave a comment
Guides, Linux, Privilege Escalation

Linux Privilege Escalation – Credentials Harvesting

Introduction

Linux-based operating systems and applications often store clear text, encoded or hashed credentials in files or in memory.

When gaining initial access to a Linux machine and performing privilege escalation enumeration steps, often passwords can be found through these means and they can be used to further escalate privileges.

There are various methods to harvest credentials in a Linux system in order to escalate privileges, the following ones are the most common and they are always worth a try.

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March 28, 2021 | by Stefano Lanaro | Leave a comment