2025 – SCRT Team Blog

Blinding EDRs: A deep dive into WFP manipulation

This article complements existing research referenced in the Further Reading section.

Endpoint Detection and Response (EDR) solutions are essential to modern defensive architectures. Their abilities to monitor, block, and respond to threats are important for containment and remediation. However, like all complex systems, EDRs rely on components that can be turned against them. One of those components is the Windows Filtering Platform (WFP), which many EDRs leverage for network traffic control and endpoint isolation.

In this article, we explore how WFP can be manipulated to either block an EDR’s connection to its cloud backend or bypass its isolation mechanisms. Both cases can effectively “blind” the EDR or reduce its effectiveness.

We observed that certain EDRs show reduced detection and response capabilities when disconnected from their cloud infrastructure. This prompted us to investigate how WFP configuration can affect an EDR’s cloud communication. During testing, we found that the same mechanism underpins the product’s “isolation” mode, meaning that manipulating WFP rules can also be leveraged to bypass its network containment features.

SonicDoor – Cracking SonicWall’s SMA 500

While attempting to compare the security level of various VPN vendors, I kept falling down the path of searching for vulnerabilities instead. This blog post details the ones I discovered in SonicWall’s SMA 500, which were patched in December 2024. This post has been delayed to coincide with my talk at SecurityFest on this exact subject.

Hijacking the Windows “MareBackup” Scheduled Task for Privilege Escalation

The built-in “MareBackup” scheduled task is susceptible to a trivial executable search order hijacking, which can be abused by a low-privileged user to gain SYSTEM privileges whenever a vulnerable folder is prepended to the system’s PATH environment variable (instead of being appended).

Insomni’hack 2025 – GuLosity writeup

The challenge

A malware was provided from a real DFIR case that occurred in January 2024. The final payloads were disarmed here, to allow the analysts to dissect the binary safely until they fully understand the execution chain of a reflective shellcode loader named GuLoader [which initially led to the delivery of Remcos RAT with an additional keylogger, but the original nasty shellcodes were replaced by benign ones to provide the most realistic challenge].

Reinventing PowerShell in C/C++

I like PowerShell, I like it a lot! I like its versatility, its ease of use, its integration with the Windows operating system, but it also has a few features, such as AMSI, CLM, and other logging capabilities, that slow it down. You know, I’m thinking about the performance gain here. I believe my scripts could run a lot faster without them.

Jokes aside, I know that a lot has already been done around this subject, but I wanted to approach the problem in a slightly different way than the existing projects. So, I worked on a way to instantiate a full-blown PowerShell console using only native code, which allowed me to do some “cleaning” at the same time.