security researchers Archives

Winsage

May 15, 2025

Windows Remote Desktop Gateway Vulnerability Let Attackers Trigger Dos Condition

The Microsoft Security Response Center (MSRC) has released critical security updates to address a significant vulnerability in the Windows Remote Desktop Gateway service, identified as CVE-2025-26677, which allows unauthorized attackers to cause denial of service (DoS) conditions. This vulnerability is rated as "High" severity with a CVSS score of 7.5 and affects multiple versions of Windows Server, including 2016, 2019, 2022, and 2025. Microsoft has provided security updates (KB5058383, KB5058392, KB5058385, and KB5058411) to rectify the issue. Additionally, another vulnerability, CVE-2025-29831, has been identified that could enable remote code execution (RCE) through a Use After Free weakness, also rated with a CVSS score of 7.5. This vulnerability requires user interaction, specifically an admin user to stop or restart the service, and affects Windows Server versions 2008 R2, 2012/R2, 2016, 2019, 2022, and 2025. Organizations are advised to prioritize patching both vulnerabilities and to review network configurations to limit exposure of Remote Desktop Gateway services. The vulnerabilities were discovered by security researchers from Kunlun Lab.

Winsage

May 14, 2025

Microsoft Scripting Engine 0-Day Vulnerability Enables Remote Code Execution Over Network

Microsoft has identified a memory corruption vulnerability in its Scripting Engine, designated as CVE-2025-30397. This vulnerability allows unauthorized remote code execution and is classified as “Important” under CWE-843 (Type Confusion). It was disclosed in the May 2025 Patch Tuesday updates and arises from improper handling of resource types. Exploitation occurs when a user clicks a specially crafted URL in Microsoft Edge's Internet Explorer Mode, potentially compromising system confidentiality, integrity, and availability. Although the attack complexity is high, successful exploitation has been confirmed in the wild. Microsoft has issued patches for all supported Windows versions, and users are advised to apply these updates and consider disabling Internet Explorer Mode to reduce risk.

Tech Optimizer

May 13, 2025

If I would ever install an antivirus, this open-source tool would be my choice, and here is why

ClamAV is a free, open-source antivirus tool that allows public scrutiny of its code, ensuring security and integrity. It is compatible with multiple platforms, including Linux, Windows, and macOS, and is suitable for self-hosted servers and virtual machines. ClamAV includes features like SigTool for managing the virus signature database and ClamBC for advanced dynamic detection capabilities. It operates through a command-based interface, which may be intimidating for some users, and requires initial configuration. Despite its thorough scanning process, it may not perform as quickly as other antivirus solutions. ClamAV is recognized for its ability to identify a wide array of potential threats without financial investment.

Tech Optimizer

May 12, 2025

Defendnot — A New Tool That Disables Windows Defender by Posing as an Antivirus Solution

Defendnot is a tool that disables Windows Defender by using the Windows Security Center (WSC) API, presenting itself as a legitimate antivirus solution. It was created by a developer named “es3n1n” and follows the removal of a previous tool called “no-defender.” The tool engages directly with WSC, which disables Windows Defender when third-party antivirus software is installed to avoid conflicts. Defendnot was developed through reverse engineering of the WSC service and involves understanding how WSC verifies processes. It registers a phantom antivirus product using COM interfaces and undocumented Windows APIs, leading Windows to disable its built-in protection. The tool requires administrative privileges to operate and adds itself to autorun to maintain its functionality after a reboot. Security experts express concern about its potential misuse by malware authors, while it also provides insights into vulnerabilities in Microsoft’s security architecture.

Winsage

May 8, 2025

Ransomware hackers target a new Windows security flaw to hit businesses

Several ransomware groups, including RansomEXX and Play, are exploiting a zero-day vulnerability in the Windows Common Log File System to elevate system privileges and deploy malware. This flaw was identified and patched during Microsoft's Patch Tuesday update in April 2024.

Winsage

May 4, 2025

Do Not Open This PDF On A Microsoft Windows PC

Microsoft has warned about the increasing use of PDF attachments in cyberattacks, particularly during the U.S. tax season. Attackers have been using PDFs with embedded links that redirect users to counterfeit pages, such as a fake DocuSign site. TrustWave SpiderLabs has identified a new campaign involving a fake payment SWIFT copy that leads to a malicious PDF containing obfuscated JavaScript, which downloads a script that conceals the RemcosRAT payload using steganography. This technique involves hiding links within images, making them difficult to detect. The latest attacks begin with phishing emails containing malicious PDFs that direct victims to harmful webpages, facilitating the delivery of RemcosRAT, a trojan that allows remote control of compromised systems. Users are advised to be cautious of emails labeled “SWIFT Copy” and to delete suspicious emails immediately.

Winsage

April 30, 2025

Unpatched Windows Shortcut Vulnerability Let Attackers Execute Remote Code

Security researcher Nafiez has discovered a vulnerability in Windows LNK files that allows remote code execution without user interaction. Microsoft has chosen not to address this issue, stating it does not meet their security servicing criteria. The vulnerability exploits specific components of LNK files, enabling attackers to create malicious shortcuts that initiate silent network connections when a user accesses a folder containing them. The exploit involves manipulating the HasArguments flag, EnvironmentVariableDataBlock, and embedding UNC paths. Microsoft defends its inaction by citing the Mark of the Web (MOTW) feature as adequate protection, despite concerns from security experts about its effectiveness. Previous vulnerabilities in LNK files have been addressed by Microsoft, and the availability of proof-of-concept code raises fears of potential exploitation by malicious actors.

Tech Optimizer

April 30, 2025

Avast Antivirus Vulnerability Let Attackers Escalate Privileges

A significant vulnerability, designated as CVE-2025-3500, has been identified in Avast Free Antivirus, allowing attackers to gain elevated system privileges and execute malicious code at the kernel level. The vulnerability has a high CVSS score of 8.8 and was publicly disclosed on April 24, 2025, shortly after a patch was implemented. It originates from inadequate validation of user-supplied data in the aswbidsdriver kernel driver, leading to an integer overflow prior to buffer allocation. Attackers must first execute low-privileged code on the target system to exploit this vulnerability. The flaw affects multiple versions of Avast Free Antivirus, specifically versions ranging from 20.1.2397 to 2016.11.1.2262. A fix was released in version 25.3.9983.922, and users are urged to update their software promptly. Security experts recommend enabling automatic updates and using standard user accounts for daily activities to mitigate risks.

Winsage

April 26, 2025

Windows 11’s Recall AI is now rolling out on Copilot+ PCs

Microsoft has announced the rollout of Windows Recall, a feature for Windows 11 systems with KB5055627 on Copilot+ PCs. Recall uses AI to capture and store visual information from the screen, allowing users to find previously viewed content by describing it in everyday language. Initially unveiled in May 2024, Recall faced privacy concerns, leading Microsoft to pause its rollout for further testing. The feature is now optional and includes enhancements to filter out sensitive information. Recall is part of Windows 11 Build 26100 and will be widely available with the May 2025 Patch Tuesday Update.

Winsage

April 24, 2025

An empty folder in Windows that «cannot be deleted» can permanently block OS updates

The inetpub folder, introduced in the April update of Windows 11 (version 24H2) as part of a fix for the CVE-2025-21204 vulnerability, has raised concerns among security researchers. It can be manipulated to block Windows updates without administrative rights by creating a symbolic link to notepad.exe, which can lead to a rollback of patches and leave the system vulnerable. Microsoft has not yet responded to this issue, and the possibility of a patch to address the new vulnerability is still open.