endpoint security | Breaking Cybersecurity News | The Hacker News

A zero-day proof-of-concept tool that stops Microsoft Defender from installing platform and signature updates by filling all available disk space was  published on GitHub  on September 19. The tool, called BigDiskBuster , has no patch, no CVE, and no Microsoft advisory. Its author, Abdelhamid Naceri, is a former Microsoft security researcher whose earlier Defender exploits were used in attacks. When updates are blocked, Defender keeps running, but its detection content grows stale. The researcher's screenshot shows Defender returning a generic Windows error when trying to update, but whether the failure raises an automatic alert is not clear from the proof-of-concept alone. Naceri said he was dismissed from Microsoft's Security Response Center in 2024 and has been releasing exploits without coordinating with the company since April. His first three Defender tools — BlueHammer, RedSun, and UnDefend — were all  exploited in live intrusions  before Microsoft...

Malware already running on a Mac can quietly take over Meta's Muse assistant and use the broad access its owner granted the app, security researcher Patrick Wardle has shown in a  proof-of-concept  released on September 21. It works by changing a hidden setting so that when the user taps the microphone and dictates a prompt, the words go to the attacker instead of Meta. The flaw is in the Mac version of Muse, and it only works if an attacker can already run code as the logged-in user. It cannot break into a Mac on its own. But Wardle told The Hacker News that a remote attacker could hijack Muse and steal its token through a ClickFix trick, which fools the user into running a single command with nothing to download or install. Muse is the personal AI agent Meta  launched this month  in the United States. Once a user turns it on, it can work across their files, email, messages, calendar, shopping and smart-home apps, using whatever access the person chooses to g...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Monday added a now-patched security flaw impacting Zyxel GS1900 series switches to its Known Exploited Vulnerabilities ( KEV ) catalog, citing evidence of active exploitation. The vulnerability, tracked as CVE-2026-7273 (CVSS score: 8.8), is a stack-based buffer overflow vulnerability that could result in arbitrary operating system (OS) command execution. "A stack-based buffer overflow vulnerability in the CGI program of the Zyxel GS1900 series switch firmware could allow a LAN-based, unauthenticated attacker to exploit the flaw and potentially execute OS commands via a crafted HTTP request," Zyxel said in an advisory released in June 2026.  The issue has been addressed in the following versions -

A fake LastPass Authenticator installer offered on GitHub installs a Windows kernel driver that shuts off antivirus and other security software before a password stealer runs if a victim downloads and runs it, researchers at LastPass and Delphos Labs said on September 17. Microsoft's own hardware-compatibility program signs the driver, scored zero detections on VirusTotal when researchers checked it in August, and was not on Microsoft's list of blocked drivers. LastPass says none of its own systems, services, or customer vaults were touched, and that the attackers only borrowed its name. The lure is a fake GitHub page (github.com/LastPass-Authenticator) that ranks in search results for terms like "LastPass Authenticator download" and looks like a real LastPass product page. Clicking the download button sends the visitor through several GitHub pages to an attacker server, which serves a large ZIP file. The real LastPass Authenticator comes from lastpass.com and ...

Cybersecurity researchers have disclosed details of a new campaign dubbed TASK#STOMP that delivers a PowerShell backdoor designed to harvest sensitive data from compromised hosts. The backdoor "automatically harvests and exfiltrates business documents, watches the filesystem for new files in real time, steals Wi-Fi passwords and clipboard contents, takes screenshots, and accepts arbitrary remote commands through two redundant, token-authenticated C2 servers," Securonix researchers Akshay Gaikwad and Aaron Beardslee said in a report shared with The Hacker News. The starting point of the infection chain is the use of "wscript.exe" to execute an encoded Visual Basic Script (VBScript) file staged on the victim's desktop ("95c9050t66.vbs"). The exact initial access pathway used to deliver the payload is unclear, although it's possible that it may have been via email-based phishing or social engineering. By giving it a completely random file nam...

Parallels Desktop for Mac has a flaw that lets an ordinary local account run code as root, the highest level of access on a Mac, software company JFrog said this week. The attack needs code already running on the machine as a normal user, so it does not work over the network. JFrog says the fix is in Parallels Desktop 27, a version that Intel Macs cannot install. Yuval Moravchick, who leads JFrog's vulnerability research team,  published the finding  on Tuesday and calls it ParaShells. The flaw is tracked as  CVE-2026-90894 , an identifier JFrog assigned itself, and JFrog rates it 7.8 out of 10. Parallels Desktop runs Windows and Linux inside virtual machines on a Mac. It installs a background service called prl_disp_service that runs as root, because its work includes setting up host networking and unpacking virtual machine packages. The flaw is on the Mac side of the product, so the machine at risk is the Mac itself rather than the virtual machines on...

Over the past year, we watched a new class of alert appear in enterprise security operations centers and grow faster than anything else in the stream: alerts that were triggered by AI tools and agents. Not attacks against AI, but the ordinary, everyday footprint of an organization using it, from developers running coding agents and non-technical staff signing consumer AI tools into corporate accounts. We reviewed AI-related activity across numerous enterprise environments. Two numbers frame everything that follows. AI-related alerts still account for only 0.43% of all SOC alerts. And that share is climbing every single month, up 685% between February and June 2026. AI is a small slice of the alert stream today and the fastest-growing slice at the same time. What makes those alerts worth a security team’s attention is not their volume but their composition. We sort everything an AI agent triggers in a SOC into three buckets: real attacks, risks, and noise, with the split being 94....

The security researcher known as Chaotic Eclipse has dropped a proof-of-concept (PoC) for yet another zero-day in Microsoft Defender. The vulnerability, codenamed ShieldCrash , is assessed to be a patch bypass for CVE-2026-69414 (CVSS score: 7.8), also called ShieldBreak , which the researcher reported last month. "Microsoft has failed to properly patch ShieldBreak CVE-2026-69414," Chaotic Eclipse said. "Under specific conditions it is still possible to trigger the exact same problem that was caused by ShieldBreak. While Microsoft fixed several things to prevent re-exploiting the issue, they missed a spot where ShieldBreak can still be exploited." The PoC demonstrates an arbitrary file read as SYSTEM with the latest version of Windows installed. All supported versions of the desktop operating system are said to be impacted. The development comes days after Redmond shipped an update to the Microsoft Malware Protection Engine to plug CVE-2026-69414. The issue...

Cybersecurity researchers have disclosed details of a complex Chromium-based post-exploitation toolkit called PEEP that masquerades as a bookmarks extension for the web browser. "Requiring prior administrative or code execution access, its installer injects the extension directly into Chrome/Edge profiles, bypassing Web Store checks and user prompts by forging Chromium's own Secure Preferences integrity values," SOCRadar said . "A native-messaging tool then extends it beyond browser telemetry to host-level command execution and file management." Once installed, the PEEP "extension" agent polls its command-and-control (C2) server ("206.237.30[.]232" or " xfjcc[.]fun ") every 30 seconds over plaintext HTTP for new commands, while exfiltrating browsing history, active-tab metadata, and session cookies. It also functions as a remote access and browser monitoring toolkit that runs host commands, steals credentials, hijacks sessions...

The security researcher known as Chaotic Eclipse (aka INFINITE NIGHTMARE, MSNightmare, and Nightmare-Eclipse) has dropped a new zero-day dubbed FalconFlank , a proof-of-concept (PoC) for a privilege escalation flaw impacting Crowdstrike Falcon. "FalconFlank is a 0-day privilege escalation that abuses the office malicious macros remediation in CrowdStrike Falcon Sensor," the researcher said in a GitHub README file, adding the cybersecurity company may already have detections for the flaw by now. "So if you want to test, you either have to add it to the exclusions or obfuscate the PoC and change the DLL load technique." The PoC, the researcher added, works in a fully updated Windows 11 25H2 machine or Windows Server 2025 with CrowdStrike Falcon. In a statement shared with The Hacker News, a CrowdStrike spokesperson said they are currently investigating the report. "We are actively investigating these claims and advise customers to disable the Microsof...

The most common way into a company last year was to ask. A web page tells the visitor to prove they are not a robot. While they read the instructions, it quietly places a command on their clipboard. Then it talks them through opening a terminal and pasting it in. The technique is called ClickFix, and it was the most common initial access method Microsoft’s team observed last year , accounting for 47% of the attacks in their notifications. Nothing arrives as an attachment, so there is nothing to scan. No vulnerability is used, so there is nothing to patch. What happens next is just as ordinary. When Bitdefender analyzed 700,000 security incidents , 84% of the high-severity ones involved binaries that were already on the machine - the same administrative tools your IT team uses every day. Nothing malicious was installed, because nothing malicious was needed. Neither technique is clever, but both are winning. And the reason is not that attackers have run out of ideas. It is that th...

The threat actor known as Silver Fox has been observed distributing the ValleyRAT backdoor disguised as a signed Chinese adware application, running the malware under a trusted process to slip past users who add such software to their antivirus exclusions. Russian cybersecurity vendor Kaspersky said the attackers built the disguise around QN Wallpaper , a genuine Chinese desktop-wallpaper tool that in its unmodified form is adware, bundling partner apps and displaying ad banners. Once installed, ValleyRAT (also tracked as Winos 4.0) hands the operator full control of the compromised machine. Kaspersky said the attack's geography and payload point to Silver Fox as the likely group behind it, and urged users to avoid software of questionable reputation and to keep it away from security-tool exclusions. "This case is a clear example of how adware and affiliate networks can turn out to be far more dangerous than they appear. ValleyRAT is a sophisticated backdoor capable of...

Claude Code reads files, runs shell commands, invokes MCP tools, and acts through the credentials available on a developer’s machine. Anthropic’s new Compliance API endpoints give security teams their clearest view yet into that activity. They also expose a larger problem: activity logs alone cannot tell you whether an agent’s access is legitimate. AI has moved from the browser tab to the endpoint with harnesses like Claude Code. They run on developers' machines, execute bash commands locally, and connect to third parties via MCP servers, skills, and plugins. All this so the user can outsource labor to the machine and focus on designing, thinking, and creating. Local agents are not a niche category. They account for 68.6% of the AI agents Token Security discovers in customer environments, and they often inherit the employee's credentials, network position, and permissions. The shift to the endpoint has major implications for security. With Claude Code, there is no ce...

An independent malware researcher has documented a previously unreported Windows backdoor, dubbed SLEEPWALKER , that stays inert in memory until a specifically crafted network packet reaches the machine and then runs commands written in a 23-instruction language of its own design. The sample is an unsigned 64-bit Windows dynamic-link library (DLL) of 59,904 bytes, built to be side-loaded into ERAAgent.exe, the Windows executable for ESET Management Agent. It impersonates Microsoft's dpapi.dll, exporting the same seven data protection functions as the genuine system library, and carries a version resource copied from ESET Management Agent. There are no domains, IP addresses or URLs built into the file, and it makes no outbound connection of its own, so an infected host can look clean to tooling that watches for connections to known-bad infrastructure. Commands arrive as bytecode rather than readable text, so recovering the encryption key yields opcodes in a format that...

Oasis Security has disclosed a weakness in NVIDIA NemoClaw that could let an attacker-controlled webpage take unauthenticated control of the local Ollama instance serving an AI agent and plant hidden instructions inside the model itself. The findings were shared with The Hacker News ahead of publication, and the report says Oasis Security reported them to NVIDIA's Product Security Incident Response Team (PSIRT) beforehand. The research carries no CVE identifier. No exploitation has been reported as of August 25, 2026. Oasis Security's head of research, Elad Luz, told The Hacker News that NemoClaw v0.0.35 fixed the issue on macOS and Linux. There is no fix on the Windows and WSL path, according to Luz, where v0.0.34 added a Windows installation that carries a warning instead. NemoClaw is NVIDIA's open source reference stack for running agents such as OpenClaw inside its OpenShell sandboxes, and Ollama is one of its supported local inference backends. The report des...

Cybersecurity researchers are calling attention to a new campaign that employs FTP banners as dead drop resolvers ( DDRs ) to deliver two previously unreported remote access trojans (RATs) tracked as E4del and PINHOLE . While threat actors are known to abuse legitimate services to point to additional command-and-control (C2) infrastructure and blend in with regular network traffic, the development marks the first time this unusual technique has been spotted in the wild. An FTP banner is a welcome message or text string that an FTP server sends to a client immediately upon connection. The mechanism allows "malware stagers to fetch commands directly from the protocol's initial response," SOCRadar said in a technical report. The modus operandi was first highlighted by the MalwareHunterTeam early last month.  However, it's worth noting that the method is a lot less stealthy than traditional web-based DDRs, as security controls are likely to flag FTP connections ...

Cybersecurity researchers have found that several websites are still actively distributing a malware family known as Weedhack to gamers by masquerading as Minecraft clients. McAfee Labs said it detected and blocked more than 6,300 attempts to access malicious sites, adding that it found lookalike gaming websites designed to mimic legitimate projects, including branding, feature lists, FAQs, installation guides, developer credits, and links to genuine GitHub repositories. Notably, one of the sites has been built using Lovable , an artificial intelligence (AI)-powered website builder, highlighting how readily available tools can further lower the barrier and make it easier to launch convincing new malicious sites. Weedhack was first documented by the cybersecurity company back in June 2026, detailing its use of SEO poisoning and YouTube to redirect traffic to the bogus domains. The attack triggers a multi-stage sequence that culminates in the deployment of JAR payloads that can ...

Cybersecurity researchers have flagged two new malware families called WordlistLoader and SynkLoader that's used to deliver next-stage payloads and likely sell access to ransomware groups. According to findings from Gen Digital, WordlistLoader is being used to deliver Amatera Stealer (aka ACR Stealer or AcridRain Stealer) via ClearFake campaigns, which employ the ClickFix (aka FakeCaptcha) technique to dupe victims into running malicious commands under the pretext of completing CAPTCHA verification checks. "Once the visitor clicks on the 'I'm not a robot' checkbox, they're walked through the well-known ClickFix flow, where a malicious command is copied into their clipboard and the victim is instructed to paste it into the Windows Run dialog and execute it, leading to the download of WordlistLoader that ultimately results in the execution of Amatera," security researcher Vojtěch Krejsa said . The ClickFix prompts are displayed on real websites th...

Cybersecurity researchers have flagged a cyber espionage campaign targeting Myanmar that uses graduation ceremony invitation lures to deliver a Go backdoor called QUICAgent. The campaign, codenamed Operation QUICSILVER , has been found to target government and information technology sectors, per Seqrite Labs. The activity is assessed to be the work of a China-nexus threat actor with moderate confidence. It was first observed in April 2026, when the attack was observed delivering a file named "HolidayNotice.pdf.exe" along with a lure that was a fabricated Belgian–Myanmar public holiday calendar. Two subsequent artifacts, each detected in June and July 2026, make use of a Virtual Hard Disk (VHD) file that activates the infection chain. Present within the VHD file is a Windows Shortcut (LNK) that mimics a PDF document. Opening the document displays a decoy PDF to the victim, an official graduation ceremony invitation that's written in Burmese and purports to be from t...

Cybersecurity researchers have disclosed details of a Chinese-speaking cybercrime group dubbed UAT-10147 that's targeting Windows and Linux web servers globally across the education, media, technology, and gaming sectors. The vast majority of the targets are located in Brazil, Bolivia, China, Canada, and Vietnam. Details of the threat activity came to light following the discovery of an open directory hosted at "139.180.197[.]150," which was observed communicating with one of the compromised machines. "The actor leveraged publicly disclosed vulnerabilities to gain initial access at scale," Cisco Talos said in a two-part report published last week. The actor employed a mixture of open-source offensive frameworks, including Metasploit , ysoserial , PentestGPT , DeepAudit, and multiple privilege escalation exploits to automate intrusion operations and establish persistence." UAT-10147 has been described as a threat actor that conducts search engine op...