In their RSA 2020 talk Advanced Persistence Threats: The Future of Kubernetes Attacks, Ian Coldwater and Brad Geesaman demonstrated that K3s, a lightweight version of Kubernetes, can be used to backdoor compromised Kubernetes clusters. This post describes how K3s can also serve as an easy command and control (C2) mechanism to remotely control compromised Linux machines.
Hidden in PEB Sight: Hiding Windows API Imports With a Custom Loader
In this post, we look at different techniques to hide Windows API imports in a program in order to fly under the radar of static analysis tools. Especially, we show a method to hide those imports by dynamically walking the process environment block (PEB) and parsing kernel32.dll in-memory to find its exported functions. Let’s dive in!
Stealthier persistence using new services purposely vulnerable to path interception
Building an Office macro to spoof parent processes and command line arguments
Most modern EDR solutions use behavioral detection, allowing to detect malware based on how it behaves instead of solely using static indicators of compromise (IoC) like file hashes or domain names. In this post, I give a VBA implementation of two techniques allowing to spoof both the parent process and the command line arguments of a newly created process. This implementation allows crafting stealthier Office macros, making a process spawned by a macro look like it has been created by another program such as explorer.exe and has benign-looking command line arguments. I am not the author of these techniques. CreditsContinue reading… Building an Office macro to spoof parent processes and command line arguments
[Write-up] Insomni’hack 2018 CTF teaser
CloudFlair: Bypassing Cloudflare using Internet-wide scan data
Cloudflare is a service that acts as a middleman between a website and its end users, protecting it from various attacks. Unfortunately, those websites are often poorly configured, allowing an attacker to entirely bypass Cloudflare and run DDoS attacks or exploit web-based vulnerabilities that would otherwise be blocked. This post demonstrates the weakness and introduces CloudFlair, an automated detection tool.
Abusing the AWS metadata service using SSRF vulnerabilities
I recently worked on a small toy project to execute untrusted Python code in Docker containers. This lead me to test several online code execution engines to see how they reacted to various attacks. While doing so, I found several interesting vulnerabilities in the code execution engine developed by Qualified, which is quite widely used including by websites like CodeWars or InterviewCake. The combination of being able to run code with network access and the fact that the infrastructure was running in Amazon Web Services lead to an interesting set of vulnerabilities which we present in this post.
[Write-up] SickOs 1.2
This post is a walkthrough of the VulnHub machine SickOs 1.2. I previously wrote one for its little sister, SickOs 1.1. I found this second version to be more challenging, but also more realistic; the author tried to mimic what one could encounter during a real engagement – and it does it pretty well.
Set up your own malware analysis lab with VirtualBox, INetSim and Burp
In this post we will set up a virtual lab for malware analysis. We’ll create an isolated virtual network separated from the host OS and from the Internet, in which we’ll setup two victim virtual machines (Ubuntu and Windows 7) as well as an analysis server to mimic common Internet services like HTTP or DNS. Then, we’ll be able to log and analyze the network communications of any Linux or Windows malware, which will unknowingly connect to our server instead of the Internet. We demonstrate the setup with a real life use case where we analyze the traffic of the infamous TeslaCrypt ransomware, a now defunct ransomware which infected a large number of systemsContinue reading… Set up your own malware analysis lab with VirtualBox, INetSim and Burp