DLLs Archives

Winsage

September 2, 2026

Fake Software Installers Disable Windows Update and Weaken Microsoft Defender

An active malware campaign is using counterfeit software-download websites to distribute malicious installers, primarily targeting users seeking popular software. This campaign has significantly affected China-based operations of multinational corporations and Chinese-speaking users. The malware, once executed, can establish persistence, undermine security measures, and communicate with attacker-controlled infrastructure. Victims span various sectors, including healthcare, manufacturing, gaming, technology, logistics, government, and education. Microsoft associates this campaign with a Chinese threat cluster called Silver Fox, known for using spoofed vendor download pages to spread Gh0st RAT and ValleyRAT. The malicious websites are hosted on .com.cn and .hl.cn domains, featuring Chinese-language content. The downloaded files are dynamically generated, and upon execution, they deploy a wrapper installer that initiates the malware payload. The malware achieves persistence through scheduled tasks and interferes with Windows Update services. The campaign establishes command-and-control communication over non-standard ports, with two identified domains linked to the activity. Microsoft Defender has detected the threat and initiated containment procedures. Kaspersky reported a related malicious installer exploiting a legitimate adware application to execute a backdoor, which captures keystrokes and clipboard contents. ValleyRAT, a sophisticated implant, can collect system information, reboot the computer, capture screenshots, and transmit logs. The attackers are motivated by cyber espionage and financial gain, targeting organizations globally. A subgroup within GoldenEyeDog, known as CuboidalCanine, has also been linked to the use of ValleyRAT, particularly in the gambling industry. In June 2026, Chinese authorities addressed cybercrime cases involving a new variant of the Silver Fox trojan.

Winsage

September 2, 2026

Fake Microsoft Edge, Kaspersky and Razer Installers Used to Compromise Windows Systems

An ongoing malware campaign is targeting Windows devices through counterfeit download pages for well-known software brands like Microsoft Edge, Kaspersky, and Razer. The campaign affects various sectors, including healthcare, manufacturing, gaming, technology, logistics, government, and education. It utilizes high-fidelity fraudulent websites that closely mimic legitimate vendors, with observed lure domains such as app-microsoft-edge[.]com[.]cn and kaspersky-lab[.]hl[.]cn. Attackers employ evasion tactics like server-side payload regeneration and create multiple copies of the same archive in quick succession. Victims are lured into downloading ZIP files that contain a bundled wrapper installer, which activates a stage-one executable in randomized directories. The malware often masquerades as legitimate software, with some payloads impersonating known applications. Persistence is achieved through scheduled tasks with unusual names, and the malware employs various evasion techniques, including deleting shadow copies and altering file permissions. Microsoft Defender has identified activity across multiple stages of the attack, including delivery, execution, and command-and-control communications. To mitigate risks, organizations are advised to block downloads from unofficial sources, enforce Tamper Protection, and implement Attack Surface Reduction rules. Indicators of compromise (IOCs) include specific lure domains and URLs associated with the campaign.

Winsage

September 1, 2026

New ClickFix campaign can deploy powerful multi-stage malware directly through Windows Terminal and PowerShell

Security researchers at Microsoft have identified a campaign named "TerminalFix" that exploits compromised websites to trick users into installing a backdoor. Users visiting these sites encounter a deceptive overlay prompting them to complete a fake Cloudflare CAPTCHA, which requires executing a malicious PowerShell command. This leads victims to inadvertently sideload dynamic link libraries (DLLs) and deploy a Python implant that creates encrypted reverse tunnels, allowing attackers to access internal networks.

Winsage

August 14, 2026

Mustang Panda Adds Signed Windows Rootkit to CoolClient Backdoor for Stealth

The threat actor known as HoneyMyte, also referred to as Mustang Panda, has been deploying an upgraded version of the CoolClient backdoor, which includes a signed Windows kernel-mode rootkit. This rootkit enhances the malware's ability to conceal malicious processes, files, registry objects, and command-and-control (C2) network information. Victims have been identified in Myanmar, Mongolia, Pakistan, and Russia, with confirmed targets including government entities. The CoolClient backdoor is deployed as a secondary access layer following an initial PlugX infection. The kernel component activates when CoolClient gains full access to the Service Control Manager (SCM) and the SeTcbPrivilege privilege. If these conditions are not met, the malware bypasses driver deployment and advances to the final-stage implant. Kaspersky has provided indicators of compromise (IoCs), including file hashes, paths, and C2 domains. In a campaign targeting Myanmar, HoneyMyte used PlugX as the initial implant to deploy CoolClient, which involved creating Microsoft Defender exclusions and renaming a legitimate executable for DLL sideloading. Persistence is achieved through a scheduled task that executes the binary with SYSTEM privileges at startup. Execution begins when a legitimate application loads a malicious DLL, which then manages persistence, registry modifications, UAC bypass, process injection, driver deployment, and C2 communications. When privileges are granted, the malware extracts a kernel driver, writes it to disk, and establishes a driver service. The driver is digitally signed with a certificate from Nanjing Ranyi Technology Co., Ltd. The driver receives configuration data from the CoolClient user-mode component and utilizes specific IOCTL requests to register trusted processes and protect filesystem and registry paths. The rootkit can limit access rights to protected processes, hide processes by unlinking them from the active process list, and deny access to protected files and directories. It also filters C2 IPv4 addresses from network information. The driver incorporates 33 IOCTL handlers, but only three were observed in use during standard execution. Kaspersky shared several file hashes related to the malware, including those for the kernel driver and malicious DLLs. This follows earlier disclosures regarding a newer CoolClient variant and a different HoneyMyte kernel-mode rootkit documented in December 2025.

Winsage

July 25, 2026

It’s impossible to recommend paid Windows cleanup utilities when Windows Sysinternals does everything for free

Many utility suites for Windows maintenance require a yearly subscription but often only aggregate basic tools. Users can achieve similar results without costs, as Windows manages routine maintenance effectively. Microsoft's Sysinternals suite offers advanced tools like Autoruns, which provides a comprehensive view of startup entries, and Process Explorer, which offers detailed process monitoring. SDelete securely deletes files beyond recovery, while RAMMap provides insights into memory usage without the risks of third-party applications. Although Sysinternals tools may lack polished interfaces, they deliver substantial functionality for users willing to learn how to use them.

Winsage

July 25, 2026

It’s impossible to recommend paid Windows cleanup utilities when Windows Sysinternals does everything for free

Windows utility suites often charge a yearly subscription fee but frequently provide only basic functionalities like startup managers and process monitors. Many features can be accessed for free through Windows' built-in capabilities. Microsoft's Sysinternals suite offers powerful alternatives, such as Autoruns, which provides a comprehensive view of all startup locations, including registry keys and scheduled tasks. Process Explorer offers detailed insights into running processes, surpassing the standard Task Manager by displaying process trees and resource usage. SDelete securely deletes files by overwriting data multiple times, making recovery nearly impossible. While Sysinternals tools are powerful, they require a learning curve and deeper engagement compared to the polished interfaces of paid utilities. Sysinternals emphasizes functionality over marketing, proving that free tools can deliver exceptional performance without compromising quality.

Winsage

July 12, 2026

Windows 95 didn’t detect installers, it ‘guessed’ based on the file name, says veteran dev — it simply checked for words like setup, install, inst, or localized equivalents

Raymond Chen, a Microsoft engineer, revealed that Windows 95 identified installation programs by analyzing executable filenames against a list of keywords, including "setup," "install," and "inst." The system would then initiate a routine to repair any compromised system files. The list included six terms: setup, install, inst, imposta, ayarla, and felrak. Chen noted redundancy in the list, suggesting "install" was unnecessary since it included "inst." For executables not matching the terms, Windows 95 scanned the executable's path for "Setup." The system maintained backup copies of frequently overwritten files in a hidden directory at C:WindowsSYSBCKUP and would restore correct versions after installers completed. File verification was often postponed until the next system boot, especially for installers that reverted to MS-DOS for file replacements. This file repair mechanism continues to influence modern operating systems, including Windows 11.

Winsage

June 30, 2026

Microsoft reveals why Windows 11 keeps saying a file is in use after you close the app, plus the fix

The 'file in use' error in Windows indicates that a file is currently being accessed by a program, preventing deletion or renaming to avoid data corruption. This error can persist even after closing an application due to reasons such as antivirus software scanning the file, network references from other devices, or files loaded as Dynamic Link Libraries (DLLs) that remain in memory. To identify the process causing the error, Mark Russinovich developed the command-line tool Handle, which shows all open file handles, and Process Explorer, which provides a graphical interface to find and manage these handles. Microsoft is integrating Sysinternals tools into PowerToys for easier access, including the File Locksmith tool that allows users to unlock files directly. A recommended workaround for the error is to rename the file instead of deleting it, as Windows permits renaming even when a file is open.

Winsage

June 25, 2026

Introduction to COM usage by Windows threats

Component Object Model (COM) is a technology in Windows that enables object activation, inter-process communication, and automation across different programming languages. Malware exploits COM interfaces for activities such as lateral movement, execution, downloading, exfiltration, persistence, evasion, system discovery, and automation of Windows and Office functionalities. Reverse engineering COM-heavy binaries involves navigating GUIDs and indirect vtable calls to understand malware mechanics. Research at the AVAR 2025 conference and CARO 2026 workshop discusses methodologies for analyzing COM binaries and case studies of malware families that utilize COM. COM is an application binary interface (ABI) model that allows software components to be reused and enables interaction between different programming languages through interfaces defined at the binary level. Distributed COM (DCOM) allows clients to activate COM objects on remote systems. COM classes are identified by unique class identifiers (CLSIDs), and interfaces by interface identifiers (IIDs). The Windows registry stores COM registration data, with classes and interfaces located under specific keys. Malware often acts as a COM client, utilizing the COM runtime to instantiate classes and request interfaces. ProgIDs provide human-readable registry entries for COM classes. The CoCreateInstance function helps create class objects by resolving CLSID registrations. All COM interfaces derive from IUnknown, which manages object lifetimes and interface querying. COM has its own security model, and identifying classes and interfaces used by malware is crucial for threat researchers. Tools like ComView and OleView.NET assist in inspecting COM registrations. The analysis workflow includes identifying activation API calls, extracting CLSID and IID values, consulting registry definitions, and mapping vtable calls. Qakbot, a banking trojan, exemplifies the use of COM in malware, with its architecture enabling malicious activities like credential theft. Dynamic analysis tools can log COM-related calls in real-time to trace execution flow. Notable malware families that utilize COM include Gh0stRAT, which uses Task Scheduler COM interfaces, and the Attor platform, which employs BITS for file transfers. WarmCookie demonstrates the use of COM for persistence through Task Scheduler. Understanding COM's role in malware is essential for cybersecurity professionals.

Winsage

June 22, 2026

MSYS2 And The No-Fuss Way To Get More GNU Into Your Windows

The Windows desktop experience has a streamlined interface, but its command line interface (CLI) offerings, particularly the cmd.exe shell, have been criticized for lacking the features found in UNIX/BSD/Linux environments. Microsoft’s transition to PowerShell has disappointed users who prefer a more traditional CLI experience. Despite Windows NT operating systems being POSIX compliant, they have historically lacked a suitable shell. MSYS2 provides a solution by offering a Linux-like experience with a Bash shell and the pacman package manager, allowing users to run shell scripts and access various tools. However, binaries compiled in MSYS2 may depend on shared libraries not included in the Windows system path. Upon installation, users can choose from different terminal options, with the UCRT terminal recommended for its usability. MSYS2 facilitates a streamlined development workflow, enabling the use of familiar tools across multiple platforms, but it does not achieve perfect integration within Windows and has some limitations, such as issues with stdout output in Bash.