Linux Security

Linux Stealth Rootkit Malware with EDR Evasion

November 28, 2021

Recently, Sandfly was contacted to investigate an incident involving a novel piece of Linux stealth malware. What made this malware interesting is it deployed a full stealth rootkit to hide itself,…

Detecting CronRAT Crontab Malware on Linux

November 28, 2021

Security researchers recently discovered a new kind of Linux malware that was hiding its payload as part of an illegal crontab entry on Linux. The malware is being used to insert card skimming…

Linux Command Line Forensics and Intrusion Detection Cheat Sheet

May 20, 2021

Below is our Linux command line forensics and intrusion detection cheat sheet along with a presentation given at Purplecon 2018 . These resources can help you investigate a Linux host for compromise…

Detecting and Investigating OpenSSL Backdoors on Linux

April 18, 2021

A nightmare for security personnel on Linux is to find a backdoor operating. This means an attacker is interacting with the host in real-time to further their intrusion. Of various backdoors that can…

Linux Malware Investigation Myth: You Don’t Need a Debugger

January 18, 2021

A big myth around investigating Linux ransomware and malware is that the first tool you need is a debugger and deep knowledge of assembly to understand what it does. It’s easy for admins and security…

Investigating Linux Process File Descriptors for Incident Response and Forensics

January 06, 2021

Let’s talk about Linux file descriptors and how to investigate a malicious process using them. What Is a File Descriptor? Since the inception of Unix (on which Linux is based), everything is a file.…