A MacSync Stealer campaign abuses Anthropic's Claude shared chat platform to host ClickFix-style malicious instructions, using Google malvertising to lure macOS users searching for Claude. Victims are tricked into running a Base64-obfuscated curl command that pipes a zsh script to execution, which in turn downloads and pipes a second stage to osascript. The stealer collects keychain data, browser credentials, cryptocurrency wallets, cloud keys, and user files, exfiltrating them in 10MB chunks via HTTP PUT before deleting all traces.
Malvertising
18 posts
ClaudeFix: Shared Claude Chats Meet ClickFix | Zscaler US Threat Landscape Alert: 30 Active Malware Families Ranked by Real Sandbox Data ANY.RUN's Malware Trends Tracker data shows that phishing-as-a-service kits now dominate the US threat landscape, with five of the top ten threats being AiTM or device-code phishing platforms that defeat MFA by stealing session cookies or OAuth tokens. Commodity RATs and info stealers remain in constant high-volume circulation, while legacy threats like Emotet and WannaCry persist on unpatched systems. Several top-ranked threats (Cobalt Strike, Qbot, Emotet, DonutLoader, Smoke Loader) function as ransomware precursors, meaning their detection should trigger urgent escalation rather than routine handling.
Vidar Stealer Unmasked: Code Signing Abuse, Go Loaders and File Inflation A financially motivated campaign active in April 2026 delivers Vidar stealer and XMRig cryptocurrency miner to victims worldwide via malvertising for fake software cracks. The campaign uses the Factory-v3 Go loader framework with per-build unique binaries, fabricated Authenticode certificates impersonating legitimate brands, file-size inflation up to 491 MB to evade sandbox analysis, and an in-memory AMSI bypass. Vidar exfiltrates browser credentials, cookies, and crypto wallets to C2 servers, while XMRig mines Monero using the pool.supportxmr.com mining pool. The operator receives Telegram notifications for each new infection.
Lost in relocation: analysis of a new loader distributing CASTLESTEALER A newly discovered Windows loader, OXLOADER, is being distributed via malicious Google Ads impersonating Node.js to deliver the CASTLESTEALER infostealer. The loader utilizes advanced evasion techniques, including control-flow flattening, anti-sandbox checks, and staging shellcode within the .reloc section of a copied system DLL, to maintain low detection rates across static engines.
Threat Actors Abuse claude.ai Shared Chat for ClickFix Malvertising Campaign A sophisticated malvertising campaign abused Google Ads to deliver ClickFix social engineering attacks disguised as popular AI developer tools and Mac utilities. The threat actors initially leveraged GitLab Pages before pivoting to weaponize claude.ai's shared chat feature, tricking macOS users into executing terminal commands that deploy the MacSync infostealer.
Unveiling ErrTraffic: inside a growing ClickFix malware distribution framework ErrTraffic is a Malware-as-a-Service framework that compromises WordPress sites and uses malvertising to deliver ClickFix social engineering lures. It leverages EtherHiding via Polygon smart contracts to dynamically resolve C2 infrastructure and distribute infostealers, RATs, and loaders.
AI brands as bait: How threat actors are using the AI hype in social engineering Threat actors are increasingly leveraging the hype around AI platforms like ChatGPT, Claude, and DeepSeek to conduct social engineering attacks. These campaigns utilize phishing, malvertising, and SEO poisoning to distribute infostealers such as Vidar or facilitate credential theft via adversary-in-the-middle (AiTM) infrastructure.
Operation FlutterBridge: macOS Malvertising Campaign Spreads New FlutterShell Backdoor Operation FlutterBridge is a widespread macOS malvertising campaign operated by the CL-CRI-1089 threat cluster, delivering a novel Flutter-based backdoor dubbed FlutterShell. The malware utilizes a dynamic WebView-based JavaScript-to-native bridge to execute arbitrary commands, hijack Google Chrome for adware revenue, and exfiltrate data, all while masquerading as legitimate, Apple-notarized applications.
Tracking TamperedChef Clusters via Certificate and Code Reuse TamperedChef (also known as EvilAI) is a widespread threat campaign distributing trojanized productivity applications via malvertising. The threat actors heavily abuse legitimate code-signing certificates and employ delayed execution techniques to evade detection, ultimately deploying information stealers, RATs, or adware onto victim endpoints after a dormancy period.
Exposing Fox Tempest: A malware-signing service operation Fox Tempest is a financially motivated threat actor providing malware-signing-as-a-service (MSaaS) to the cybercrime ecosystem. By abusing Microsoft Artifact Signing via stolen identities, they generate short-lived, fraudulent code-signing certificates that allow threat actors like Vanilla Tempest to bypass security controls and deploy payloads such as the Oyster backdoor and Rhysida ransomware.
Donuts and Beagles: Fake Claude site spreads backdoor A malvertising campaign is leveraging a fake Claude AI website to distribute a malicious MSI installer. The infection chain employs DLL sideloading via a legitimate G DATA executable to execute DonutLoader, which ultimately deploys a novel backdoor dubbed 'Beagle' for remote command execution and file manipulation.
InstallFix and Claude Code: How Fake Install Pages Lead to Real Compromise The InstallFix campaign leverages malvertising to distribute fake Claude AI installation pages, tricking users into executing malicious MSHTA commands. This initiates a multi-stage, fileless infection chain utilizing a ZIP/HTA polyglot, COM object abuse, and AMSI/SSL bypasses to deliver a payload associated with RedLine Stealer. The campaign demonstrates advanced evasion tactics, including the use of victim-unique C2 subdomains derived from machine fingerprints.
Tools Change. Habits Don’t. We Saw It Up Close. A Huntress engineer encountered a malvertising campaign via a Google sponsored search result for 'Claude Code'. The malicious link delivered a multi-stage macOS malware utilizing base64 encoding, gzip compression, and obfuscated AppleScript to bypass Gatekeeper and attempt extraction of Claude Code credentials from the macOS keychain.
Investigating Storm-2755: “Payroll pirate” attacks targeting Canadian employees Storm-2755 is a financially motivated threat actor targeting Canadian organizations with 'payroll pirate' attacks. By leveraging SEO poisoning and Adversary-in-the-Middle (AiTM) techniques, the actor steals session tokens to bypass legacy MFA, maintains persistence using the Axios HTTP client, and alters direct deposit information to steal employee salaries.
Patterns, Pirates, and Provider Action: What We Learned Working with Keitaro Cybercriminals are widely abusing the Keitaro ad tracking software as a Traffic Distribution System (TDS) to route victims to malware, crypto drainers, and scams. By utilizing cracked licenses, advanced traffic filtering, and third-party cloaking integrations, threat actors effectively evade detection while precisely targeting users based on device and geolocation.
No Reach, No Risk: The Keitaro Abuse in Modern Cybercrime Distribution Cybercriminals are increasingly abusing the Keitaro adtech platform to optimize the distribution of malware, phishing, and scams. By leveraging Keitaro's built-in tracking, cloaking, and traffic distribution capabilities, actors can efficiently target victims, evade detection, and scale operations across multiple threat types including wallet drainers and infostealers.
Inside Keitaro Abuse: A Persistent Stream of AI-Driven Investment Scams Threat actors are extensively abusing the legitimate Keitaro Tracker platform to conduct domain cloaking, facilitating large-scale, AI-driven investment and tech support scams. By combining traffic distribution systems with AI-generated deepfakes and localized lures, attackers effectively evade automated security scanners while maximizing victim engagement and conversion rates.
Banners, Bots and Butchers: An Automated Long Con Targeting Japan, Asia, and Beyond A hybrid investment scam campaign is targeting users in Asia and globally by combining malvertising with pig butchering tactics. Threat actors use RDGA-generated domains and AI chatbots on popular messaging apps to automate social engineering, impersonate financial experts, and extract funds from victims.
