endpoint detection

Winsage
March 1, 2026
Cybercriminals are exploiting a legacy feature in Windows File Explorer, specifically the WebDAV protocol, to distribute malware and bypass traditional security measures. Despite Microsoft deprecating native WebDAV support in November 2023, it remains active on many systems. Attackers use WebDAV to deceive victims into executing malicious payloads by sending links that connect File Explorer directly to remote servers, avoiding web browsers and their security warnings. They employ methods such as direct linking, URL shortcut files, and LNK shortcut files to deliver exploits. The primary objective of these campaigns, which surged in late 2024, is to deploy Remote Access Trojans (RATs), with 87% of Active Threat Reports involving multiple RATs like XWorm RAT, Async RAT, and DcRAT. These campaigns predominantly target corporate networks in Europe, with many phishing emails written in German and English. Attackers use short-lived WebDAV servers hosted on Cloudflare Tunnel demo accounts to obscure their infrastructure. Security analysts are advised to monitor unusual network activity from Windows Explorer and educate users to verify addresses in File Explorer.
Tech Optimizer
January 22, 2026
A large-scale campaign is exploiting the truesight.sys Windows security driver from Adlice Software’s RogueKiller antivirus to disable endpoint detection and response (EDR) and antivirus solutions, facilitating the deployment of ransomware and remote access malware. This attack utilizes over 2,500 validly signed variants of the driver, allowing attackers to manipulate legacy driver signing rules to load pre-2015 signed drivers on Windows 11 machines. The vulnerable TrueSight driver exposes an IOCTL command that enables attackers to terminate security processes, providing them with kernel-level access to bypass user-mode protections. The infection chain typically starts with phishing emails or compromised sites, leading to the installation of a downloader that retrieves additional malicious components. The malware establishes persistence and deploys an EDR killer module targeting nearly 200 security products. Once defenses are disabled, the final payload, often a remote access trojan or ransomware, executes with minimal visibility, completing the attack in as little as 30 minutes.
Tech Optimizer
January 19, 2026
PDFSIDER is a sophisticated backdoor malware that bypasses modern endpoint detection and response systems. It is distributed through targeted spear-phishing campaigns that exploit vulnerabilities in legitimate PDF software. The malware is delivered via spear-phishing emails containing ZIP archives with a trojanized executable disguised as the PDF24 App. When executed, it uses DLL side-loading to load a malicious DLL (cryptbase.dll) alongside the legitimate PDF24.exe, allowing attackers to execute code without detection. PDFSIDER establishes encrypted command-and-control channels using the Botan 3.0.0 cryptographic library with AES-256 in GCM mode and operates mainly in memory to minimize detectable artifacts. It collects system information and executes commands through hidden cmd.exe processes. The malware employs advanced techniques to evade detection in sandbox and virtual machine environments, including checks for available RAM and debugger presence. Indicators of compromise include the malicious file cryptbase.dll and various clean files associated with the legitimate PDF24 application. Organizations are advised to enforce strict controls on executable files, provide user awareness training, and monitor DNS queries and encrypted traffic to detect PDFSIDER communications. The malware's behavior aligns with tactics used in state-sponsored espionage rather than financially motivated cybercrime.
Winsage
January 12, 2026
A new tool named EDRStartupHinder was unveiled on January 11, 2026, which allows attackers to inhibit the launch of antivirus and endpoint detection and response (EDR) solutions during the Windows startup process. Developed by security researcher Two Seven One Three, it targets Windows Defender and various commercial security products on Windows 11 25H2 systems by redirecting essential system DLLs during boot using the Windows Bindlink API and Protected Process Light (PPL) security mechanisms. The tool employs a four-step attack chain that includes creating a malicious service with higher priority than the targeted security services, redirecting critical DLLs to attacker-controlled locations, and modifying a byte in the PE header of the DLLs to cause PPL-protected processes to refuse loading them. This results in the termination of the security software. EDRStartupHinder has been tested successfully against Windows Defender and other unnamed antivirus products, demonstrating its effectiveness in preventing these security solutions from launching. The source code for EDRStartupHinder is publicly available on GitHub, raising concerns about its potential misuse. Security teams are advised to monitor for Bindlink activity, unauthorized service creation, and registry modifications related to service groups and startup configurations to detect this attack vector. Microsoft has not yet issued any statements regarding patches or mitigations for this technique.
Search