Infostealers Target Claude, Cursor, Codex and Other AI Agents to Steal Credentials and Sensitive Data
Gen Digital researchers report infostealer families Amatera, Remus and CallbackBeaver now harvest Claude, Cursor and Codex agent data, including tokens and MCP configs.
Gen Digital researchers found commodity infostealers extending their collection rules to local AI coding agent data from Claude, Cursor, Codex, Cline, Continue and OpenCode on Windows and macOS. Amatera targets Cline and Continue, Remus targets Claude, Cursor and OpenCode, and CallbackBeaver added Claude and Cursor with more than 5,000 samples observed in 30 days; Djinn Stealer hits Claude, Codex, Gemini, Cline, OpenCode and Kilo on macOS. Stolen data includes access and refresh tokens, prompt histories, conversation databases and MCP configurations holding API keys, potentially exposing connected source-control, cloud and ticketing systems. Remus is assessed as a Lumma Stealer variant using EtherHiding C2 resolution via Ethereum smart contracts.
Hackers deploy Linux rootkit on F5 BIG-IP APM devices, hiding web shell in memory
Sophos analyzed a Linux rootkit, tracked as PoisonedRefresh, on hacked F5 BIG-IP APM devices hiding an in-memory web shell linked to exploited CVE-2025-53521.
Sophos and ESET analyzed an implant (named PoisonedRefresh by ESET) deployed on compromised F5 BIG-IP APM appliances, which serves enterprise, financial, government, and public sector deployments. The second-stage payload intercepts __libc_start_main, hooks Apache's APR module loader (apr_dso_load), RC4-encodes key strings, and rewrites PHP file reads in memory to embed a web shell inside legitimate scripts like apm_css.php3, full_wt.php3, and webtop_popup_css.php3, leaving on-disk files unchanged. A related installer component infects /usr/sbin/httpd, persists across BIG-IP upgrade images, modifies SELinux configuration, and deploys the payload. The malware also creates a Unix domain socket at /run/bigtlog.pipe that hands authenticated local connections to /bin/bash; F5 links the activity to CVE-2025-53521, an unauthenticated RCE in BIG-IP APM already exploited in the wild.
Week in review: AiTM phishing kit used to hijack AWS accounts, year-long malware campaign targets HR
Rust Supply Chain Attack Puts Build-Time Malware in Crates with 245 Million Downloads
Compromised maintainer account published malicious versions of popular Rust crates with 245M downloads, delivering a build-time payload via typosquatted proc-macro1 dependency.
The Rust Project deleted malicious releases of arrayref 0.3.10, internment 0.8.7, and append-only-vec 0.1.9 from crates.io after a compromised maintainer account added a typosquatted dependency, proc-macro1, whose build script downloaded and executed a remote payload during compilation. Each malicious version was online for 86 to 107 minutes on August 20, 2026, before deletion. The build script disabled TLS validation and deployed OS-specific implants on Unix, macOS, and Windows, with builds alone sufficient to trigger execution. Wiz Research confirmed active exploitation, noting the impacted packages appear in 35% of cloud and code environments and over 75% of Rust-using environments; arrayref alone has 245 million all-time downloads and 403 dependent crates.
KREMLIN Banking Malware Bypasses Chrome Security to Steal Banking Sessions
Elastic Security Labs details KREMLIN, a Brazilian banking malware that implants malicious Chrome and Edge extensions by forging Chromium integrity values to steal banking sessions.
Elastic Security Labs tracks the KREMLIN banking malware operation as REF9334, active since at least May 2025 across seven campaigns primarily targeting 12 Brazilian banks. The malware is installed by a victim-run JavaScript loader, achieves scheduled-task persistence, and side-loads a malicious DLL via SentinelOne's SentinelMemoryScanner.exe. It modifies Chrome and Edge Secure Preferences files, enables developer mode, and regenerates Chromium MAC values to silently install extensions, while extracting browser encryption material including the newer App-Bound OSCrypt key. An Ethereum smart contract serves as a dead-drop resolver for C2 config; Elastic disrupted over 1,500 infections via a canary domain.
Hackers Deploy New SloppyRAT via ClickFix to Enable Ransomware Lateral Movement
Zscaler ThreatLabz reports SloppyRAT, a new Windows RAT delivered via ClickFix lures that supports reconnaissance, reverse SOCKS proxying, and lateral movement for ransomware affiliates.
Zscaler ThreatLabz first observed SloppyRAT in June 2026, delivered through multi-stage ClickFix chains that abuse finger.exe, a renamed curl.exe, and IronPython to load a reflective Python payload. The C++ implant implements 47 PowerShell-like commands via native APIs and direct syscalls, modifies Microsoft Defender settings, and establishes a reverse SOCKS proxy that lets operators pivot into internal networks. It is linked to CastleLoader and CastleRAT components and uses certificate-pinned HTTPS C2 with an EtherHiding fallback via Polygon JSON-RPC. Zscaler assesses it as an intrusion-enablement tool for ransomware operations, though flawed persistence logic suggests the family is still under development.
Hackers Target Claude, Cursor and Codex AI Agents to Steal Tokens and Prompt Histories
Gen Digital found infostealers like Amatera and Remus stealing AI coding agent tokens, prompt histories, and MCP configs from infected Windows and macOS machines.
Gen Digital analysts observed Amatera and Remus detections among tens of thousands of protected Windows users over three months, with Amatera targeting Cline and Continue data and Remus targeting Claude, Cursor, and OpenCode. CallbackBeaver added Cursor and Claude to its collection scope with more than 5,000 samples in 30 days, while macOS-focused Djinn Stealer has been associated with Claude, Codex, Gemini, Cline, OpenCode, and Kilo. The stealers harvest access and refresh tokens, prompt histories, and MCP configuration files that can expose source control, ticketing, databases, cloud resources, and sensitive project context for follow-on fraud. Many stealers add targets via remotely managed rules, meaning this is an adaptation of existing infostealers rather than a new vulnerability in the AI tools themselves.
ToxicPanda 2.0 Gets a Major Upgrade, Expanding Attacks Across 16 Countries
Zimperium documents ToxicPanda 2.0, an Android banking trojan now targeting 349 financial institutions in 16 countries via ADB privilege escalation and overlay credential theft.
Zimperium's zLabs documented ToxicPanda 2.0, an Android banking trojan expanding from 16 targeted apps to 349 financial institutions across 16 countries, with 167 remote commands. It poses as a dropper, abuses VPN permissions to block Google Play Protect while installing a hidden payload, then uses the Accessibility Service for screen monitoring and overlay-based credential theft. It automates enabling Android Wireless Debugging and completes the pairing handshake to gain ADB shell access for privilege escalation, and overlays fake lock screens to steal device PINs. Previously unfinished commands are now operational and samples are served from AWS-hosted storage buckets.
Shai-Hulud's Reach Just Grew to 469 Credential Locations. Here's What That Means
GitGuardian found the Shai-Hulud infostealer worm now scans 469 credential locations, including CI/CD and AI tool configs, expanding supply-chain risk.
GitGuardian researchers found that a recent Shai-Hulud worm variant scans for credentials across 469 locations in developer environments, CI/CD tooling, cloud configurations, and AI tool configs, up from 189 paths in earlier variants. The worm reuses stolen credentials to pivot from developer workstations to source code, cloud infrastructure, and package publishing channels, turning credential theft into forward-propagating supply chain attacks. The analysis urges defenders to prioritize removing long-lived package publishing tokens in favor of short-lived OIDC-based trusted publishing, citing recent Docker and GitHub Actions improvements.
ThreatsDay: 296K IoT Botnet, 100+ Water Systems Targeted, SharePoint RCE Chain + 27 New Stories
Weekly ThreatsDay bulletin details a ShinyHunters-style social engineering hit on ReliaQuest, the 296,000-device Dysphoria IoT botnet, and several new malware families.
ReliaQuest confirmed a social engineering attack on August 22, 2026, in which an attacker used a fake SSO page and MFA push approval to gain brief view-only access to an identity dashboard, with tactics matching ShinyHunters, which has since listed the firm on its leak portal. The Shadowserver Foundation reported the Dysphoria botnet has compromised nearly 296,000 IoT devices for DDoS attacks and recently added residential proxy capability. Cisco Talos documented JWR, an operator-driven phishing-as-a-service framework linked to The Outsider that harvests credentials, identity documents, and 2FA codes over an encrypted WebSocket. New malware coverage includes the Octagon Android fraud bot ($1,400/month), the C2Looper Rust backdoor delivered via ClickFix, and the Aeternum loader that moved C2 to the Polygon blockchain.
Hackers Use ClickFix Lures to Deploy MacSync Stealer and Bypass macOS Security.
ClickFix malvertising campaigns deliver MacSync, a macOS infostealer sold as MaaS that bypasses Gatekeeper via Terminal commands and steals credentials.
Threat actors use ClickFix social-engineering lures, SEO poisoning, and malvertising impersonating brands like Claude, ChatGPT, Zoom, and Docker to trick users into pasting curl-to-zsh commands into Terminal, evading Gatekeeper and notarization checks. The MacSync Stealer (formerly Mac.c, emerged April 2025, linked to developer 'Mentalpositive') is a 64-bit Mach-O stager with single-byte XOR string obfuscation that daemonizes, polls C2 with custom API-key headers, streams AppleScript payloads into osascript, and persists via fake LaunchAgents. It steals browser credentials, Keychain data, SSH keys, session tokens, and crypto wallets, exfiltrating archives in 10MB HTTP PUT chunks. Microsoft documented more than 30 related MacSync domains.
Hackers Disguise CHOSEN BRICK Malware as AI Apps, Antivirus Software and MRI Results
NCSC, FBI, and AIVD warn Iranian state-linked actors deliver CHOSEN BRICK Windows spyware via fake AI apps, antivirus installers, and MRI-result lures.
A joint advisory from the UK NCSC, FBI, and Dutch AIVD details CHOSEN BRICK (FBI tracking name: HEAVYGRAM), Iranian state-linked Windows spyware targeting dissidents, activists, and journalists worldwide since at least 2025. Lures impersonate Pictory, RunwayML, Norton Antivirus, Telegram, Adobe Flash Player, and KeePass, and operators pivot conversations from corporate to personal devices to bypass enterprise controls. The spyware persists via Registry Run keys, adds Microsoft Defender exclusions, uses per-victim Telegram bots for command-and-control, and exfiltrates screenshots, audio, email, and chat data via Telegram and cloud services, with some victim data appearing on pro-Iranian leak sites.
The extension you never installed: KREMLIN forges Chrome's own integrity checks to steal banking sessions
Elastic details KREMLIN, a Brazilian banking malware whose malicious Chrome/Edge extension forges Chromium integrity checks to steal sessions.
Elastic Security Labs tracked operation REF9334 and its KREMLIN toolkit, a Brazilian banking malware campaign impersonating twelve banks across seven campaigns since May 2025. The infection chain uses multi-stage obfuscated JavaScript loaders with sandbox checks (file and process counting), scheduled-task persistence, and an Ethereum smart contract acting as a dead-drop resolver for C2 and payload URLs, abusing Archive.org for hosting. The malicious browser extension bypasses Chromium integrity mechanisms by manipulating Secure Preferences and regenerating required HMACs and App-Bound encrypted hashes. Threat Command disrupted over 1,500 infections by registering the kill-switch canary domain.
ClearFake Deploys Crypto Stealer That Uses Vulnerable Driver to Kill EDR Security Tools
Cisco Talos details ClearFake's fake-CAPTCHA chain deploying ZigCryptoStealer with a BYOVD attack that kills EDR processes, observed at a Ukrainian government organization in April 2026.
ClearFake compromises websites, injects JavaScript via a malicious Cloudflare Worker, retrieves instructions from BNB Smart Chain contracts (EtherHiding), and presents a fake Google CAPTCHA that tricks Windows users into pasting a command that loads a remote library over WebDAV via rundll32. The crypto-stealer branch uses DLL side-loading with a signed Chrome component to launch ZigCryptoStealer, which hijacks clipboard cryptocurrency addresses, alongside a signed but vulnerable Windows driver used in a BYOVD attack to terminate EDR processes. A parallel branch delivers Amatera secondary payloads that install a hidden remote-access client providing operator desktop control, with Cisco Talos tracking the remote-loader activity as UAT-10820. Talos observed unusual remote library execution at a Ukrainian government organization in April 2026 and assesses the attacks are part of a broader theft operation rather than a single targeted campaign.
New Android malware encrypts files, steals data, and harasses victims
Zimperium details Mantax Otax, an Android malware combining ransomware, spyware, and harassment, spread via phishing APKs to Indonesian users.
Zimperium researchers report Mantax Otax is distributed through malicious APKs hosted outside Google Play via phishing and social engineering, then abuses Accessibility permissions for broad device control. It encrypts files with a C2-provided AES key on Android 9 and older, adds '.enc' extensions, and hosts ransom chats on Firebase; researchers exposed attacker chats via a Firebase misconfiguration. The malware steals lock-screen PINs, SMS one-time codes, contacts, WhatsApp and Telegram chats, and captures screens via MediaProjection, while version 2 adds jumpscare overlays and text-to-speech harassment. Google Play Protect already detects and blocks it on up-to-date devices via the App Defense Alliance.
AmnesiaStealer Gives Attackers Live Control of Victims’ macOS Browsers
Jamf Threat Labs analyzed AmnesiaStealer, a Rust-based macOS infostealer spread via fake GitHub pages that also grants live hidden browser control.
AmnesiaStealer is a three-stage Rust infostealer distributed through counterfeit GitHub download pages using the ClickFix technique, a lure shared with Atomic Stealer and MacSync campaigns. It harvests the keychain, 16 Chromium browsers, Apple Notes, Telegram and documents, reusing a password captured via a fake installer dialog. A third-stage stream module clones the victim's browser profile headlessly and lets operators drive the session via Chrome DevTools Protocol, while persistence uses a LaunchDaemon impersonating Apple's com.apple.ReportCrash.agent. On macOS 26 it may replace Chrome's Safe Storage key, a useful detection signal.
HVNC Backdoor Targets LATAM Organizations with Fake Tax and DocuSign Lures
A custom HVNC backdoor is targeting Latin American financial organizations via fake DocuSign and NFe tax-document lures, giving attackers hidden persistent remote access.
ANY.RUN researchers analyzed a multi-stage phishing campaign delivering a custom HVNC backdoor to banking and financial organizations in Latin America. The chain starts with fake DocuSign and NFe tax-document pages that serve per-visitor ZIP archives, followed by an LNK dropper, an NSIS loader, and a 64-bit backdoor masquerading as Windows Update Assistant. The implant provides hidden remote desktop control, keystroke monitoring, Firefox data theft, Startup-folder persistence, and EDR-aware behavior, communicating over TCP/27015.