local privilege escalation Archives

Winsage

May 25, 2026

Windows zero-days expose gaps in built-in security protections

Two Windows zero-day vulnerabilities, YellowKey and GreenPlasma, have been identified. YellowKey targets the Windows Recovery Environment (WinRE) on Windows 11 and Windows Server 2025, allowing attackers with physical access to bypass BitLocker protections using a USB device. GreenPlasma affects Windows 10, Windows 11, and Windows Server environments with active Collaborative Translation Framework Monitor (CTFMON) sessions, enabling local privilege escalation from a standard user account to SYSTEM-level privileges. Both vulnerabilities require either physical or local access to exploit. Microsoft has not yet released patches for these vulnerabilities, prompting organizations to enhance their security measures and operational resilience. Recommendations include reassessing physical security, limiting local administrative access, and implementing multifactor authentication and robust credential management practices.

Winsage

May 21, 2026

Microsoft Defender Zero-Day Vulnerabilities RedSun and UnDefend Actively Exploited on Windows 10, 11, and Server (April 2026 CVE Analysis)

In April 2026, two zero-day vulnerabilities, RedSun and UnDefend, were discovered in Microsoft Defender, affecting Windows 10, Windows 11, and Windows Server platforms. These vulnerabilities allow attackers to escalate privileges to SYSTEM and bypass Defender’s protections. RedSun exploits a flaw in Defender's remediation process, enabling low-privileged users to overwrite critical system files. UnDefend allows attackers to disrupt Defender’s updates, keeping it outdated and ineffective. Both vulnerabilities are actively being exploited, with attackers leveraging them to gain persistent access and deploy ransomware. The primary targets are organizations using Windows systems with Defender enabled, particularly in sectors like finance, healthcare, and government. Mitigation strategies include applying updates for related vulnerabilities, monitoring for suspicious activities, and implementing additional security measures.

Winsage

May 18, 2026

Old Windows Flaw Returns to Spotlight With MiniPlasma Exploit

Security researcher Chaotic Eclipse has introduced a Windows exploit called MiniPlasma, which may allow privilege escalation from standard user accounts to SYSTEM level access, even on patched versions of Windows. This exploit is linked to CVE-2020-17103, a flaw in the Windows Cloud Filter driver that was addressed by Microsoft in December 2020. Tests have reportedly demonstrated the exploit functioning on a patched Windows 11 Pro system, achieving SYSTEM access from a standard user account. The exploit involves an undocumented registry-key path within the .DEFAULT user hive, raising concerns about the effectiveness of the 2020 fix. There is a discrepancy between public and Canary builds of Windows 11, with the exploit working on the public build but not on the Canary build. Microsoft’s April 2026 Patch Tuesday updates included another entry related to the Windows Cloud Files Mini Filter Driver elevation-of-privilege issue. Defenders are advised to monitor the CVE-2020-17103 record for further clarification regarding the status of the original fix and the implications of the MiniPlasma exploit.

Winsage

May 17, 2026

New Windows ‘MiniPlasma’ zero-day exploit gives SYSTEM access, PoC released

A cybersecurity researcher, known as Chaotic Eclipse, has released a proof-of-concept exploit for a Windows privilege escalation zero-day vulnerability called "MiniPlasma," which allows attackers to gain SYSTEM privileges on fully patched Windows systems. The vulnerability affects the cldflt.sys Cloud Filter driver and was reported by Google Project Zero in September 2020, assigned the identifier CVE-2020-17103, and claimed to be resolved by Microsoft in December 2020. However, Chaotic Eclipse asserts that the vulnerability remains unpatched. Testing confirmed that the exploit works on Windows 11 Pro, enabling command prompt access with SYSTEM privileges from a standard user account. Will Dormann, a vulnerability analyst, verified the exploit's effectiveness but noted it did not work in the latest Windows 11 Insider Preview Canary build. The exploit leverages the undocumented CfAbortHydration API to manage registry key creation improperly. Chaotic Eclipse has previously disclosed other Windows zero-day vulnerabilities and claims their actions are a protest against Microsoft's handling of vulnerabilities.

Winsage

May 16, 2026

Windows 11 and Microsoft Edge Hacked at Pwn2Own Berlin 2026

On May 14, Pwn2Own Berlin 2026 began, where researchers earned ,000 for 24 unique zero-day vulnerabilities. Cheng-Da Tsai, also known as Orange Tsai, achieved a significant Edge sandbox escape, earning ,000, and later exploited Microsoft Exchange for remote code execution, earning an additional ,000. Tsai accumulated 17.5 Master of Pwn points, contributing to DEVCORE's lead with ,000 in total earnings. Other researchers, including Angelboy and TwinkleStar03, earned ,000 for an Improper Access Control vulnerability, while Marcin Wiązowski and Kentaro Kawane also contributed successful exploits. By the end of Day One, DEVCORE led with ,000, and the event featured a prize pool exceeding ,000,000 across 31 targets. As of Day Two, a total of ,750 had been awarded for 39 unique vulnerabilities, with DEVCORE leading at 40.5 points and ,000 in earnings.

Winsage

May 13, 2026

Windows BitLocker zero-day gives access to protected drives, PoC released

A cybersecurity researcher known as Chaotic Eclipse has released proof-of-concept exploits for two unpatched vulnerabilities in Microsoft Windows: YellowKey, a BitLocker bypass, and GreenPlasma, a privilege-escalation flaw. The YellowKey vulnerability affects Windows 11 and Windows Server 2022/2025, allowing unauthorized access to BitLocker-protected volumes by exploiting the Windows Recovery Environment. The exploit can be executed using specially crafted 'FsTx' files on a USB drive or directly on the EFI partition. Independent researcher Kevin Beaumont has validated the exploit, which can bypass BitLocker protections even in a Trusted Platform Module (TPM) environment. The GreenPlasma vulnerability allows unprivileged users to create arbitrary memory-section objects, potentially leading to privilege escalation. Chaotic Eclipse has expressed dissatisfaction with Microsoft's handling of bug reports, prompting the public disclosure of these vulnerabilities. Microsoft has stated its commitment to investigating security issues and updating affected devices.

Winsage

May 10, 2026

Microsoft Confirms KB5083769 Breaks Macrium and Acronis Backups

Microsoft's April 2026 Windows security update, KB5083769, may disrupt image-mount operations for backup applications such as Macrium Reflect, Acronis Cyber Protect Cloud, UrBackup Server, and NinjaOne Backup due to the addition of the psmounterex.sys kernel driver to its Vulnerable Driver Blocklist. This action was taken to address a high-severity buffer overflow vulnerability, CVE-2023-43896. The inclusion of this driver in the blocklist has rendered several backup products inoperable, and Microsoft will not retract the block for security reasons. Administrators can use Event ID 3077 in the Code Integrity log to confirm that the blocklist is causing the failures. Microsoft advises updating backup applications to versions that include necessary driver protections instead of uninstalling or pausing the security patch. Additionally, the April updates have caused other issues, such as failures in Windows Server installations and devices booting into BitLocker recovery mode.

Winsage

April 25, 2026

New Windows RPC Vulnerability Lets Attackers Escalate Privileges Across All Windows Versions

PhantomRPC is a significant architectural vulnerability in the Windows Remote Procedure Call (RPC) framework that allows local privilege escalation to SYSTEM-level access across all Windows versions. Discovered by Kaspersky's Haidar Kabibo at Black Hat Asia 2026, this vulnerability stems from the RPC runtime's failure to verify the legitimacy of a responding server during calls to offline or disabled servers. Attackers can exploit this by setting up a malicious RPC server that impersonates a legitimate endpoint, using the RpcImpersonateClient API to escalate privileges from low-privileged accounts to SYSTEM or Administrator levels. Five distinct exploitation paths have been identified: 1. gpupdate.exe coercion: An attacker can intercept an RPC call made by the Group Policy Client service when executing gpupdate /force, granting SYSTEM-level access if TermService is disabled. 2. Microsoft Edge startup: Launching msedge.exe triggers an RPC call to TermService, allowing privilege escalation from Network Service to Administrator via a spoofed endpoint. 3. WDI background service: The Diagnostic System Host polls TermService regularly, enabling an attacker to exploit this without user interaction. 4. ipconfig.exe and DHCP Client: Running ipconfig.exe initiates an RPC call to the DHCP Client service, allowing a Local Service attacker to elevate privileges if DHCP is disabled and a fake server is present. 5. w32tm.exe and Windows Time: An attacker can expose a named pipe endpoint, allowing them to impersonate any privileged user executing the Windows Time executable. The vulnerability was reported to Microsoft on September 19, 2025, but Microsoft categorized it as moderate severity and closed the case without a patch, as the attack requires SeImpersonatePrivilege, which is granted by default to certain accounts. Organizations are advised to implement defensive measures such as enabling RPC monitoring, ensuring legitimate services are running, and restricting SeImpersonatePrivilege. Kaspersky has provided tools for auditing environments for exploitable RPC call patterns through the PhantomRPC GitHub repository.

Winsage

April 19, 2026

Windows Defender Security Flaws Actively Exploited by Hackers

Three vulnerabilities in Microsoft Defender, known as BlueHammer (CVE-2026-33825), RedSun, and UnDefend, are being actively exploited by hackers. BlueHammer has been patched, while RedSun and UnDefend remain unpatched. The public release of exploit code has accelerated real-world attacks, affecting Windows 10, Windows 11, and Windows Server systems. Attackers have begun exploiting these vulnerabilities, leading to concerns about privilege escalation, disruption of security updates, and the rapid spread of attacks.

Winsage

April 18, 2026

‘They mopped the floor with me and pulled every childish game they could’: Disgruntled researcher releases second major Windows zero-day — claims Microsoft ‘would ruin my life, and they did’

A new zero-day vulnerability in Microsoft Defender has been disclosed by a researcher known as "Chaotic Eclipse," who has created a proof-of-concept exploit called "RedSun." This vulnerability allows local privilege escalation to SYSTEM level on Windows 10, Windows 11, and Windows Server when Microsoft Defender is active. The vulnerability has attracted attention from antivirus vendors, with some detecting it on VirusTotal due to an embedded EIRCAR in the executable. Chaotic Eclipse previously disclosed another vulnerability named BlueHammer, which also allowed local attackers to gain SYSTEM or elevated permissions. The researcher expressed dissatisfaction with Microsoft's vulnerability disclosure process, recounting negative interactions with the company. A Microsoft spokesperson stated the company's commitment to investigating security issues and supporting coordinated vulnerability disclosure.