disclosure Archives

Winsage

August 17, 2026

⚡ Weekly Recap: VMware Exploits, Windows 0-Day, MCP Attacks, Browser Hijacks and More

A suspected advanced persistent threat (APT) group linked to China exploited a newly patched vulnerability in VMware vCenter (CVE-2026-59310), which has a critical CVSS score of 9.8, allowing for arbitrary code execution and the deployment of Babuk-derived ransomware. A recently patched vulnerability in Apple macOS (CVE-2026-65400) has been exploited to deploy a cryptocurrency miner, granting unauthorized root access. The Lazarus Group from North Korea exploited a zero-day vulnerability in Microsoft Windows, targeting defense and aerospace sectors. GeoServer patched a critical SQL injection vulnerability that was actively exploited. A new macOS malware, Amnesia Stealer, targets users through ClickFix attacks, stealing data and allowing real-time access to authenticated sessions. A novel attack technique named GhostSplice can manipulate AI coding assistants. Research revealed a method exploiting Chromium's DevTools Protocol for data theft. Noteworthy CVEs this week include CVE-2026-68820, CVE-2026-58231, and multiple others across various platforms. A high-severity command injection flaw in FileRun allows remote code execution. An advanced ClickFix attack has been reported, deploying sophisticated malware. A heap overflow vulnerability in Citrix NetScaler was patched after indications of exploitation. A new malware loader targeting Portuguese-speaking users has been identified. A significant reduction in exposed Automatic Tank Gauge systems has been observed. A phishing campaign targeting Brazil has been detected, and an F.B.I. agent faces charges for unauthorized crypto withdrawals. Authorities in Ukraine dismantled fraudulent call centers, and a North Carolina man was sentenced for cyber extortion. Unauthorized access to sensitive data by the ExfilSquad group has been confirmed. LightSpy activity linked to China has been detected in over 13 countries. A supply chain attack exposed over 2,500 companies, and an Azure exfiltration campaign has exposed millions of enterprise records.

Winsage

August 16, 2026

Microsoft threatened legal action, and this researcher just dropped a new Windows bug anyway

Microsoft has faced legal warnings regarding the disclosure of vulnerabilities, but security researcher Nightmare Eclipse has revealed a new exploit called ShieldBreak that targets Windows Defender. This vulnerability allows attackers to escalate privileges from a low-level user account to full system access on Windows 10, Windows 11, and Windows Server 2025. The proof of concept for ShieldBreak is available as a downloadable application, requiring execution to activate the exploit. Security expert Will Dormann confirmed that Windows Defender must be activated for the attack to succeed. ShieldBreak builds upon a previous exploit named RoguePlanet, which Microsoft patched inadequately, allowing ShieldBreak to bypass the fix. Microsoft is currently investigating the reported vulnerability, but no patch has been released yet.

Winsage

August 16, 2026

LeakWatch CW 33/2026: Windows Zero-Day, AMD, Intel and Malware

- The August Patch Tuesday release included 421 vulnerabilities, with 236 affecting Windows, highlighting CVE-2026-68820, a critical use-after-free vulnerability that allows privilege escalation to SYSTEM level without user interaction. - CISA added CVE-2026-68820 to its Known Exploited Vulnerabilities Catalog, confirming its active exploitation. - AMD's Ryzen Master software has vulnerabilities, including CVE-2025-54512 (DLL hijacking) and CVE-2026-0465 (use-after-free), which could allow code execution with elevated privileges. - AMD's advisory on CVE-2026-6726 and CVE-2026-6727 indicates vulnerabilities in the TPM 2.0 reference code affecting Ryzen platforms, leading to potential information disclosure. - Intel's advisories included updates for microcode, Wi-Fi software, and NPU drivers, with CVE-2026-20760 addressing privilege escalation risks. - Google’s Chrome update on August 11 fixed five high-severity vulnerabilities, including use-after-free flaws. - Gunra malware has evolved into a ransomware-as-a-service model using a double-extortion strategy. - WindRelay malware combines SpyNote RAT with an NFC relay component, allowing attackers to relay NFC communication between a victim's bank card and a remote device. - The findings emphasize the need to view vulnerabilities as part of potential attack chains, highlighting the complexity of modern cybersecurity threats.

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

August 14, 2026

APT group HoneyMyte upgrades CoolClient: the backdoor gets a kernel-level Windows rootkit

CoolClient is a sophisticated backdoor family linked to the HoneyMyte APT group, actively used in cyber-espionage campaigns targeting organizations in Asia and Russia since its initial disclosure in 2022. It has capabilities such as keylogging, clipboard theft, credential harvesting, and system reconnaissance. Investigations in 2023 revealed enhancements, including clipboard theft and HTTP traffic interception. By late 2025 and into 2026, a variant was noted that could deploy a signed kernel-mode driver as a Windows service, improving its stealth and operational capabilities. In a recent campaign targeting Myanmar, the HoneyMyte group used PlugX to deploy CoolClient components. They configured Microsoft Defender to exclude a fake Windows Defender installation directory and a renamed executable, defender.exe, to avoid detection. Persistence was achieved through a scheduled task that executed defender.exe with SYSTEM privileges at startup, which sideloaded the malicious libngs.dll to initiate the CoolClient execution chain. The latest CoolClient variant has a multi-stage execution chain, including: - defender.exe / Sang.exe: Exploited legitimate application for DLL sideloading. - libsrapc.dll: Benign dependency for the Sangfor application. - libngs.dll: First-stage loader that decrypts and loads the next stage. - loadcert.ini: Second-stage DLL implementing core functionalities. - cert.ini: Final-stage implant for command and control communication. - time.ini: Configuration file for CoolClient. The execution begins with the legitimate Sangfor application loading libngs.dll, which uses obfuscation to conceal its operations. The second stage, loadcert.ini, is injected into synchost.exe and performs tasks including persistence and process injection. The kernel-mode driver deployment routine involves decrypting time.ini, verifying privileges, and creating a service to execute the driver, enhancing stealth. The deployed kernel-mode driver, msagent.sys, is digitally signed and helps hide processes, files, and registry objects, making detection more difficult. The latest variant continues to target organizations consistent with previous HoneyMyte activities, with confirmed victims in Myanmar, Mongolia, Pakistan, and Russia, including government entities. The deployment of CoolClient as a secondary backdoor after a PlugX infection indicates a strategic approach to maintain access to compromised systems. The malware is confirmed as a new variant of CoolClient associated with the HoneyMyte threat group, with the kernel-mode driver marking a significant advancement in its capabilities.

Winsage

August 13, 2026

Microsoft-vendetta hacker has a new zero day that gives system privileges on fully patched Windows

Nightmare Eclipse has released a new zero-day exploit called ShieldBreak, which can bypass Microsoft's RoguePlanet patch (CVE-2026-50656) and allow attackers to gain SYSTEM privileges on fully patched Windows 10, Windows 11, and Windows Server systems. The exploit has been confirmed by security expert Kevin Beaumont, who provided detection methods for it. ShieldBreak is the tenth zero-day from Nightmare Eclipse since April and was released shortly after Microsoft's monthly Patch Tuesday. The exploit allows local privilege escalation and has a 100% success rate on the latest version of Windows 11 and Windows Server 2025, while Windows 10 remains vulnerable. Microsoft is aware of the vulnerability and is investigating it, emphasizing the importance of coordinated vulnerability disclosure. Previous exploits from Nightmare Eclipse include LegacyHive and GreatXML, with earlier vulnerabilities having been patched but recent ones still unaddressed. Microsoft had threatened legal action against Nightmare Eclipse in May but later reconsidered its approach to vulnerability disclosure.

Winsage

August 13, 2026

Researcher threatened by Microsoft finds new critical bug in Windows | Researcher had accused Microsoft of mistreatment

A vulnerability in Microsoft Defender, named ShieldBreak, has been revealed by security researcher Nightmare Eclipse, allowing malicious actors to gain complete system-level access to a user's device. Microsoft has previously warned against public disclosure of vulnerabilities and suggested potential legal repercussions for researchers who do so outside its protocols. Users of Microsoft Defender are advised to remain vigilant regarding this vulnerability.

Winsage

August 12, 2026

After Microsoft threatened legal action, a security researcher publishes a new Windows zero-day bug

A security researcher named Nightmare Eclipse has discovered a vulnerability in Windows, called ShieldBreak, which allows hackers to gain system-wide access to users' devices and sensitive data by exploiting a flaw in Windows Defender. The vulnerability affects Windows 10, Windows 11 (including version 25H2), and Windows Server 2025. A proof-of-concept exploit has been provided, requiring users to run a Windows application to trigger the vulnerability. Security researcher Will Dormann confirmed that Windows Defender must be enabled for the exploit to work. Microsoft has not yet released a patch for ShieldBreak, which is classified as a zero-day vulnerability. This discovery follows previous vulnerabilities disclosed by Nightmare Eclipse, including RoguePlanet, for which Microsoft issued an inadequate patch. The situation has heightened tensions between the researcher and Microsoft regarding the handling of bug reports, especially after Microsoft threatened legal action against researchers disclosing zero-days outside established protocols. The disclosure of ShieldBreak occurred shortly after Microsoft's monthly security patch releases, which have been increasing in number.

Winsage

August 12, 2026

ShieldBreak: New Windows Zero-Day Bypasses Microsoft’s RoguePlanet Patch

Chaotic Eclipse, a security researcher, has revealed a proof-of-concept (PoC) for a new vulnerability called ShieldBreak, which is a zero-day flaw in Microsoft Defender that bypasses the patch for the previously identified CVE-2026-50656 (RoguePlanet). This vulnerability could allow attackers to execute code at the SYSTEM level on affected Windows systems. Chaotic Eclipse tested the PoC on the latest versions of Windows 11 and Windows Server 2025, achieving a 100% success rate. Windows 10 and its server editions are not supported by the PoC but remain vulnerable. Microsoft had issued security updates for RoguePlanet, which has a CVSS score of 7.8, affecting the Malware Protection Engine and representing a local privilege escalation issue. Chaotic Eclipse has previously disclosed two other zero-day vulnerabilities, YellowKey and GreenPlasma, which affect BitLocker and the Windows Collaborative Translation Framework, respectively. Microsoft criticized the public disclosure of these vulnerabilities as irresponsible and emphasized the importance of Coordinated Vulnerability Disclosure.

AppWizard

August 12, 2026

Saber Interactive denies replacing writer with ChatGPT on its new driving game, but says it will use AI for dialog ‘as the number of passengers in the game is infinite’

Saber Interactive's upcoming game, Rideshare "Stimulator," has sparked controversy due to comments from former lead writer Stella Sacco, who claimed she was replaced by ChatGPT during development. Sacco stated that all passenger voices in the game were also AI-generated, raising concerns about transparency in the game's development. She attributed the decision to use AI to higher-ups at Saber, despite her supervisor's support for her involvement. Saber Interactive has denied Sacco's claims but acknowledged the use of AI in the game. The game's Steam page promotes "unique and unpredictable passenger stories," but Sacco's remarks suggest a disconnect between the marketing narrative and the creative process, particularly regarding the lack of disclosure about AI usage.