denial-of-service Archives

Tech Optimizer

September 23, 2026

BigDiskBuster PoC Blocks Windows Defender Updates

A new tool named BigDiskBuster has been released on GitHub, which disrupts Microsoft Defender Antivirus by preventing it from installing updates. It does this by consuming available disk space during the update process, causing Defender to remain on its current version and unable to receive new platform or signature updates. BigDiskBuster operates as a local denial-of-service technique and requires prior access to the target machine to execute. The tool was created by researcher Abdelhamid Naceri, known as Nightmare Eclipse, who has previously worked on similar projects. As of now, there is no CVE identifier, patch, or advisory from Microsoft regarding this issue.

Winsage

September 23, 2026

New Windows Defender zero-day blocks Microsoft antivirus updates

Security researcher Abdelhamid Naceri, known as Nightmare Eclipse, released a zero-day exploit called BigDiskBuster that targets Microsoft Defender, preventing antivirus updates and leaving systems vulnerable. BigDiskBuster operates across all supported Windows versions and must run in the background to block updates. Naceri has previously released a similar exploit called UnDefend and has a history of releasing multiple zero-day exploits since April 2026 amid a dispute with Microsoft. Two weeks before BigDiskBuster, he introduced another exploit named ShieldCrash, which grants SYSTEM access and circumvents a patched flaw. Naceri's recent exploits include tools like LegacyHive, BlueHammer, RedSun, YellowKey, GreenPlasma, and MiniPlasma, all targeting Microsoft Defender and other Windows components. Microsoft has warned of potential legal action against malicious activities but has not commented on BigDiskBuster.

AppWizard

September 10, 2026

Tor VPN Beta brings isolated app-by-app Tor routing to Android

The Tor Project has launched Tor VPN Beta for Android, allowing mobile applications to route traffic through the Tor network, expanding beyond web browsing. This development was driven by user demand for privacy tools to bypass internet censorship, particularly in restrictive regions. The concept originated in 2021, and after initial testing and user feedback, the beta was announced on September 9. Tor VPN creates a separate Tor circuit for each application, enhancing privacy by complicating activity correlation across apps. Users can select which applications use Tor, and the interface has been improved for easier management. The beta version 1.4.0 includes support for WebTunnel bridges to disguise Tor connections as standard encrypted traffic. Usability testing revealed issues with exit-node selection, leading to a design change that requires users to connect to Tor before choosing an exit. Tor VPN is built on the Arti implementation of the Tor protocol and the Onionmasq networking layer, ensuring stability and component sharing. The software supports reproducible builds and is available via F-Droid and APK downloads. A security review in June 2025 found no major flaws but identified some issues being addressed. Tor VPN is currently in beta and focuses on enhancing circumvention capabilities and usability rather than competing with commercial VPNs on speed. Users in censored areas are advised to configure bridges for access.

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.

AppWizard

August 14, 2026

Threema messenger says DDoS attacks disrupted its service for two days

Threema experienced significant disruptions due to large-scale DDoS attacks, rendering the service inaccessible for several hours on Tuesday and causing intermittent outages on Wednesday morning. The attacks targeted both Threema and its Swiss colocation partner, Nine, with service being unavailable from 7:30 p.m. to 11:30 p.m. CEST on Tuesday. By 12:23 p.m. on Wednesday, normal operations were restored. The security of Threema's systems and user data remained intact despite the service availability issues. The nature of the attacks made mitigation challenging, as attackers modified their methods rapidly. Threema's status page faced issues during the outage, and communication was conducted via email and social media. In response, Threema is implementing specialized upstream DDoS protection and plans to enhance its status page to provide monitoring for future disruptions.

Winsage

July 14, 2026

Microsoft Just Patched a Record 570 Flaws in Windows

Microsoft's July Patch Tuesday update addresses 570 vulnerabilities, including three critical zero-days. The vulnerabilities include 254 elevation-of-privilege flaws, 17 security feature bypasses, 145 remote-code-execution issues, 102 information disclosures, 16 spoofing vulnerabilities, and 35 denial-of-service vulnerabilities. Among these, 59 bugs are classified as "critical." The three zero-days patched are CVE-2026-56155 (elevation of privilege in Active Directory Federation Services), CVE-2026-56164 (elevation of privilege in Microsoft SharePoint Server), and CVE-2026-50661 (security bypass in Windows BitLocker). The update is recommended to be installed as soon as possible, and users can check for updates through the Windows Update settings.

Winsage

June 11, 2026

Microsoft Patches Record 206 Flaws, Including Three Zero-Days and Critical RCE Bugs

Microsoft announced an update addressing 206 security vulnerabilities, including 39 classified as Critical and 167 as Important. The vulnerabilities include 63 privilege escalation, 56 remote code execution, 30 information disclosure, 27 spoofing, 20 security feature bypass, 7 denial-of-service, and 3 tampering vulnerabilities. Notable critical flaws include CVE-2026-45657 (use-after-free in Windows Kernel, CVSS score 9.8), CVE-2026-47291 (integer overflow in Windows HTTP.sys, CVSS score 9.8), and CVE-2026-44815 (stack-based buffer overflow in Windows DHCP Client, CVSS score 9.8). Microsoft also addressed vulnerabilities related to BitLocker bypass (CVE-2026-45585 and CVE-2026-50507) and introduced a new registry setting to mitigate risks associated with CVE-2026-49160 (denial-of-service vulnerability). The increase in patches is attributed to the use of artificial intelligence in vulnerability discovery, with the current year's reported vulnerabilities surpassing the total from all of 2018.

Winsage

June 10, 2026

Microsoft’s biggest-ever Patch Tuesday fixes 206 bugs, including 3 zero-days

Microsoft's recent Patch Tuesday release addressed 206 security vulnerabilities, marking the largest update since the program began in October 2003. Among these, 32 vulnerabilities are classified as critical, including three zero-day vulnerabilities that were disclosed before patches were available, though none are reported to be actively exploited. Notable vulnerabilities include: - CVE-2026-50507 in Windows BitLocker, with a CVSS score of 6.8, allowing unauthorized bypass of security features through physical attacks. - CVE-2026-49160 in HTTP.sys, with a CVSS score of 7.5, which can be exploited for remote denial-of-service attacks. - CVE-2026-45586 in the Windows Collaborative Translation Framework (CTFMON), with a CVSS score of 7.8, which could grant SYSTEM privileges to attackers.

Winsage

June 10, 2026

Microsoft patches record 198 Windows bugs in June update – and 3 are zero days

Microsoft's latest Patch Tuesday addressed 198 security vulnerabilities, the most extensive update in recent memory. Among these, 32 flaws are classified as critical, and three are zero-day vulnerabilities. The updates are detailed in KB articles: KB5094126 for Windows 11 versions 24H2 and 25H2, KB5093998 for version 23H2, and KB5094127 for Windows 10. The updates will automatically download and install, but users must verify their installation status and reboot their computers for changes to take effect. The vulnerabilities addressed this month are attributed to advancements in artificial intelligence, with companies like Microsoft leveraging AI models to expedite the identification and resolution of security flaws. The three zero-day vulnerabilities include one that allows an attacker to gain Windows System privileges through a flaw in file link resolution, another that could facilitate a denial-of-service attack via an HTTP vulnerability, and a third related to a flaw in Windows BitLocker that could enable data capture from an unpatched PC. Additionally, the update introduces new features to Windows 11, including new Secure Boot certificates, a Low Latency Profile for enhanced performance, support for shared audio devices for multiple Bluetooth connections, webcam functionality across multiple applications, and the ability to assign a custom name to the user folder during setup.

Winsage

June 1, 2026

Windows Server vulnerability can grant system privileges with just a malformed packet — domain controllers are being exploited in the wild

Microsoft is facing scrutiny due to a critical remote execution vulnerability, CVE-2026-41089, rated at 9.8, affecting Windows Server domain controllers from version 2012 onward. This vulnerability allows unauthenticated users on the same network to send malformed UDP packets to a domain controller, potentially granting unauthorized system access or causing a reboot, leading to denial-of-service scenarios. The vulnerable service is Netlogon, and there are no immediate mitigations available; patches will be released on May 12. The vulnerability could allow attackers to create multiple accounts with various access levels, compromising the security of entire networks. Cybersecurity experts recommend patching all linked domain controllers simultaneously. The vulnerability is caused by a buffer overflow in the Netlogon service due to a field in a network packet exceeding its expected size. A GitHub repository exists with proof-of-concept code that can crash the LSASS service. Additionally, Microsoft is in conflict with security researcher Chaotic Eclipse, who has published zero-day exploits following a breakdown in negotiations.