Microsoft has resolved a bug that caused Windows Defender to crash after a recent security update, resulting in 0xc0000005 access violation errors on some affected systems. Microsoft Defender is a security software designed to provide real-time protection against malware, viruses, ransomware, and spyware on Windows, macOS, Linux, Android, and iOS devices. According to reports on social media and Microsoft's support site, users began seeing "Threat service has stopped. Restart it now" error messages on Windows 10 and Windows 11 devices starting Tuesday afternoon, prompting some affected customers to reinstall the operating system. "Beginning this morning, quick or full scans are failing, and will occasionally fail to the point where the Defender service needs to be restarted," one Windows system admin said.
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) warned that hackers are exploiting a critical-severity remote code execution (RCE) flaw in the Windows Internet Key Exchange (IKE) Service Extensions component. Also known as MS-IKEE, this is a set of additional capabilities Microsoft added to the IKE Protocol, including authentication via cryptographically generated addresses (CGAs), denial-of-service protection, and easier interoperability with non-Internet Protocol Security (IPsec)–capable peers. Tracked as CVE-2026-33824, this RCE vulnerability impacts all supported Windows 10, Windows 11, and Windows Server releases, and it allows attackers without privileges to gain code execution by sending maliciously crafted packets to unpatched Windows systems through UDP ports 500 or 4500.
Microsoft tracked over 30 MacSync Stealer domains by focusing on behavioral patterns, revealing a campaign targeting passwords, keys, wallets and other data. Domain blocking is a losing game when the thing you’re blocking can register a new domain faster than you can add it to a list. That’s the exact problem Microsoft Defender Experts ran into while tracking MacSync Stealer, a macOS-focused information stealer that RST Cloud first flagged for swapping out its command-and-control infrastructure almost immediately after getting publicly outed. Microsoft detailed how its experts stopped chasing individual domains and started tracking the behaviors that stayed constant underneath them. Instead of tracking individual domains, Microsoft looked at recurring request patterns, HTTP headers and other behaviors. This allowed its researchers to link more than 30 domains to the same campaign and determine that the infrastructure was doing more than just sending commands to infected Macs. It was also being used to collect, stage and exfiltrate stolen data. “MacSync Stealer is a macOS-focused information stealer that relies on changing infrastructure to deliver payloads, communicate with compromised devices, and exfiltrate data. Earlier reporting by RST Cloud identified the threat through a limited set of domains and documented rapid command-and-control (C2) replacement after public disclosure.” reads the report published by Microsoft. “Microsoft Defender Experts expanded that view by correlating recurring endpoints and network behaviors across the activity. This behavior-led approach connected more than 30 domains and showed that the infrastructure supported more than C2 communication, extending into active collection, staging, and exfiltration.” The infection chain starts with a trick rather than an exploit. Victims get social-engineered through a technique known as ClickFix, tricked into pasting or running commands directly in macOS Terminal, and once that shell session fires, curl pulls down attacker-controlled payload content from a path formatted as /curl/[token]. Then, native macOS tools decode and unpack the payload, and an AppleScript-driven layer takes over, blending Unix commands like sh, cp, rm, and killall with osascript calls that make the whole chain look more like ordinary system scripting than malware. Once active, the stealer focuses on valuable data. The malicious code looks for macOS Keychain data, saved browser passwords and cookies, SSH keys, AWS credentials, Kubernetes configurations and files in common user folders. It also searches for Ledger and Trezor wallet data, showing that the malware targets users with valuable credentials and assets rather than simply collecting random browser history. What actually confirms exfiltration, rather than just suspicious traffic, is the upload mechanism itself. Collected data gets staged under temporary paths, compressed into an archive, split into chunks, and pushed out through HTTP PUT requests carrying parameters like upload_id, chunk_index, and total_chunks. “The staged archive was uploaded through rotating infrastructure using curl and HTTP PUT requests. Observed requests included –data-binary, API-key headers, macOS User-Agent string, upload_id values, chunk_index values, and total_chunks parameters.” states Microsoft. “These upload traits confirmed active data exfiltration and provided durable hunting pivots even when domains rotated. “ The researchers pointed out that the exfiltration method stays recognizable even when the destination keeps changing. RST Cloud’s follow-up work backs up how consistent this infrastructure actually is under the surface. Using the same recurring URI patterns, RST Cloud surfaced eleven additional candidate domains and found a static API-key value shared across four confirmed command-and-control domains, even while the build token attached to each deployment kept rotating. A shared static key sitting inside otherwise rotating infrastructure is exactly the kind of detail that makes automated evasion look less impressive up close. The attack wraps up with cleanup, deleting temporary archives, staging folders, and lock files after the upload completes. Microsoft notes this reduces what’s left sitting on disk, but it doesn’t erase the behavioral sequence itself. “After exfiltration, the malware removed temporary archives, staging folders, lock files, and other artifacts. Although this cleanup reduced on-disk evidence, the sequence of archive creation, chunked upload, and deletion can still provide a useful behavioral correlation for defenders.” concludes Microsoft. For anyone defending Mac fleets, the practical takeaway here isn’t a list of domains to block, since that list will be stale within days. It’s building detection around the recurring shape of the attack itself: shell sessions spawning curl with those specific flag patterns, osascript chaining rapidly into network activity, and archives appearing under /tmp/sync* right before outbound PUT traffic starts. Chase the pattern, not the address, because the address was never going to sit still long enough to matter. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, malware)
U.S. Cybersecurity and Infrastructure Security Agency (CISA) adds Apple macOS, Microsoft SharePoint, Broadcom VMware vCenter, and Microsoft IKE flaws to its Known Exploited Vulnerabilities catalog. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added the following vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog: CVE-2026-33824 (CVSS score: 9.8) – Microsoft Internet Key Exchange (IKE) Service Extensions Double Free Vulnerability CVE-2026-55040 (CVSS score: 9.1) Microsoft SharePoint Weak Authentication Vulnerability CVE-2026-59310 (CVSS score: 9.8) Broadcom VMware vCenter Path Traversal Vulnerability CVE-2026-65400 Apple macOS Improper Authentication Vulnerability CVE-2026-33824 is a Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution Vulnerability. This critical flaw in Windows IKE service extensions could allow remote attackers to execute code on affected systems. Systems with IKE enabled are at risk, though blocking UDP ports 500 and 4500 can reduce exposure from external threats. However, internal attackers may still exploit it for lateral movement, so rapid patching is strongly recommended. CVE-2026-55040 is a critical SharePoint authentication bypass. An unauthenticated attacker can exploit weaknesses in JWT validation to forge tokens and impersonate any SharePoint user, including administrators. “A critical authentication bypass vulnerability exists in SharePoint Server Subscription Edition’s JWT token validation pipeline. The root cause is a chain of four distinct weaknesses that, when combined, allow an unauthenticated remote attacker to forge a valid JWT and impersonate any SharePoint site user.” wrote Rapid7. The exploit chain works by sending a JWT with “alg: none” in the outer header so no signature is required, using SharePoint’s own STS certificate thumbprint to resolve a signing key without verification, and then passing a non-empty but never-verified signature like “AAAA.” The result is a fully forged token that SharePoint accepts as legitimate. Defused researchers observed attackers using the Rapid7 POC for CVE-2026-55040 against our SharePoint their honeypots. CVE-2026-59310 flaw is a Path Traversal Vulnerability that allows an attacker with network access to execute arbitrary code. “VMware vCenter contains a directory traversal vulnerability in the Syslog server. Broadcom has evaluated the severity of this issue to be in the Critical severity range with a maximum CVSSv3 base score of 9.8.”states the advisory.”A malicious actor with network access to vCenter may exploit this issue to execute arbitrary code.” CVE-2026-65400 is an Improper Authentication Vulnerability that sits in macOS’s built-in Screen Sharing feature, the remote desktop tool baked into every Mac.On August 15, 2026, the Dutch National Cyber Security Centre confirmed active exploitation of a critical macOS authentication flaw, less than two weeks after Apple shipped the fix. Apple’s fix improved how the system manages authentication state, closing a gap that let attackers on the network authenticate to Screen Sharing without valid credentials at all. Apple patched this issue with the release of macOS Tahoe 26.6.1, macOS Sequoia 15.7.9, and macOS Sonoma 14.8.9, crediting researcher Alfredo Pesoli (@__rev) at Bynario Atlas (bynar.io) for the discovery. “An attacker on the network may be able to authenticate to Screen Sharing without valid credentials” reads the advisory. According to Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities, FCEB agencies have to address the identified vulnerabilities by the due date to protect their networks against attacks exploiting the flaws in the catalog. Experts also recommend that private organizations review the Catalog and address the vulnerabilities in their infrastructure. CISA orders federal agencies to fix the flaws by August 21, 2026 Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, CISA)
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Tuesday added four critical vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, stating they are being exploited in the wild. The shortcomings added to the KEV catalog are listed below - CVE-2026-65400 (CVSS score: 9.8) - An improper authentication vulnerability impacting Apple macOS that could allow an
Microsoft Defender Experts have linked more than 30 web domains to MacSync Stealer, a macOS-focused information stealer, after correlating recurring endpoint and network behaviors across changing infrastructure, tracing the malware from payload retrieval through data collection, staging, and exfiltration. The tech giant said it required multiple endpoint and network behaviors to align before
We provide guidance for preparing for and mitigating large-scale credential attacks, focusing on recent campaigns targeting security vendors' devices. The post Threat Brief: Mitigating Large-Scale Credential Attacks (Updated August 18) appeared first on Unit 42.
Researchers tested 31 million patterns to disrupt surveillance AI, with promising results but significant gaps between simulation and real-world use. The Kansas City-based cybersecurity researcher Bill Swearingen spent the past year doing something that sounds almost too simple to work: printing patterns, watching cameras fail to detect them, and repeating. TechCrunch reports that after roughly 31 million tests, he can now generate patterns on demand that block license plate readers and surveillance cameras from recognizing whatever the pattern covers, whether that’s a person or a vehicle. The project is called noRecognition, and the core idea isn’t stealth in the traditional sense. The camera still records everything just fine. What breaks is the detection layer sitting on top of the footage, the software that flags license plates, tracks faces, or spots “activity of interest” across thousands of hours of video. Swearingen’s patterns don’t hide you from the lens; they make the algorithm looking through that lens shrug and move on. Swearingen, co-founder of the SecKC meetup, said his project started for personal reasons. He became concerned about the growing number of surveillance cameras in his town and the possibility of being tracked while attending a protest. What started as a simple experiment later became a reinforcement learning system. He taught the model to create patterns, learn from failures and keep improving. Over time, it learned how to avoid detection by several camera systems. Every time a pattern failed and got detected, the system adjusted and tried again, eventually learning to defeat multiple detection algorithms simultaneously rather than just one at a time. The research dashboard behind the project, published at sandbox.norecognition.org, goes considerably deeper into the numbers than the headline claim suggests, and it’s refreshingly upfront about what’s proven versus what isn’t. The team states its overall objective plainly as “one pattern that defeats every detector,” and by their own account that goal remains only partially met. Their strongest validated result against a detector extracted directly from a real deployed surveillance camera sits at 61.7% non-detection across held-out test subjects, a solid number, but nowhere near total, and still a digital simulation rather than a real-world fabric test. That distinction matters more than it might seem. Most of the dashboard’s headline figures are explicitly labeled as digital, simulated results, meaning the pattern was tested against a virtual camera and printed ink model rather than an actual garment photographed by an actual camera in the field. The gap between “works in simulation” and “works when Donut Media wraps a real 2009 Toyota Yaris in it,” which is the physical test Swearingen ran live at DEF CON, is exactly the gap this kind of research has to close before anyone should treat it as a reliable, everyday privacy tool. “On Friday at the Def Con cybersecurity conference in Las Vegas, Swearingen ran his first real-world test. With help from Donut Media, the test involved covering a 2009 Toyota Yaris with one of Swearingen’s newest patterns to see if the car would be invisible to detection by a Flock camera.” reports TechCrunch. “We proved it was effective,” said Swearingen, though the wheels were a challenge. The video of the demo will be out in the next few weeks, said Donut Media.” That DEF CON demo is where things got concrete. Swearingen covered a car in one of his newest patterns and tested it against a Flock Safety camera, the kind widely deployed for automated license plate reading across the US. He said the test proved effective, though the vehicle’s wheels turned out to be a persistent weak point, curved surfaces apparently don’t cooperate with flat printed patterns the way a car door does. Source Tech Crunch – A photo of a 2009 Toyota Yaris at the Def Con conference in Las Vegas, covered in a pattern made by Bill Swearingen, as part of a test to see if it can defeat surveillance camera detection. Image Credits:Bill Swearingen / Donut Media Swearingen is not publishing his best patterns because he does not want camera makers to easily find and block them. Instead, he is using crowdfunding to develop and sell printed products such as T-shirts and hoodies, with vehicle wraps possibly coming later. It is still unclear whether the project will become a practical privacy tool for everyday users or remain mainly a DEF CON demonstration. Its real effectiveness will depend on how well the patterns work on real clothing, in different weather and camera conditions. Follow me on Twitter: @securityaffairs and Facebook and Mastodon Pierluigi Paganini (SecurityAffairs – hacking, Surveillance camera)
Security controls can block a familiar attack method while missing quieter ways to achieve the same objective. Picus Security's Blue Report 2026 shows how prevention rates can vary dramatically by technique and why behavioral testing is needed to uncover those gaps.
Microsoft says some users are experiencing issues searching in Microsoft 365 apps, including Outlook on the web, Outlook desktop, SharePoint Online, and OneDrive. According to an incident report seen by BleepingComputer and tracked under MO1456424 in the Microsoft 365 Admin Center, the root cause is what Microsoft describes as a recent deployment that causes resource utilization problems. "Impact is specific to some users served through the affected infrastructure who are attempting to search for content in SharePoint Online, OneDrive, Outlook on the web, or Outlook desktop," Microsoft said. "Our investigation identified that a recent deployment introduced a resource utilization inefficiency issue, leading to impact." Microsoft says it has already developed a fix and deployed it to reduce resource pressure and restore service for all affected Microsoft 365 users.
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