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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.

Elastic Security Labs · 3d agoMalware in the wild

Malicious Twitch Extension Exposes OAuth Tokens of 30,000 Chrome and Firefox Users

Malicious 'Twitch Enhanced Viewer | JeetBot' browser extension stole live OAuth session tokens from roughly 31,000 Chrome and Firefox users.

Socket.dev found the cross-store extension 'Twitch Enhanced Viewer | JeetBot' rerouted Twitch playlist requests through operator-controlled proxies, attaching the victim's account-level OAuth token as a URL parameter where it could be logged in cleartext. About 30,000 Chrome and 552 Firefox installs were exposed, with tokens forwarded for nearly every watched channel to infrastructure tied to a Russian commercial bot service. The stolen bearer token enables chat, whisper, account-setting access and channel-point spending without the password or 2FA.

Cyber Security Newsupdated · 2d agofirst · 2d agoMalware in the wild 2 sources

Twitch extension with 30K installs exposes users’ OAuth tokens

Twitch extension with 30,000+ installs exfiltrates users' OAuth session tokens to Russian-run JeetBot proxy servers.

Socket analysis shows the "Twitch Enhanced Viewer | JeetBot" browser extension, with over 30,000 installs on the official Chrome and Firefox stores, captures the Twitch web client's authorization header and extracts the user's OAuth token. The token is appended as an auth= URL parameter to video playlist requests routed through JeetBot proxy servers, landing in cleartext request logs retrievable by the Russian-language bot service vendor; ten hardcoded Russian-language channels are exempted. Earlier versions used more explicit token exfiltration, and the extension remained live in both stores at publication. Socket recommends removing the extension, disconnecting all Twitch sessions, and re-authenticating.

BleepingComputer · 2d agoMalware in the wild

Malware bypasses browser checks to force install Chrome, Edge extensions

Elastic Security Labs detailed KREMLIN, a Brazilian banking malware that silently installs malicious Chrome and Edge extensions, with 1,515 confirmed infections.

Elastic Security Labs analyzed KREMLIN, a toolkit used by a Brazilian operation in at least seven campaigns since May 2025 that impersonates 12 banks to trick users into opening a JavaScript file disguised as a bank receipt or invoice. After anti-sandbox checks, it downloads Node.js, persists via a scheduled task, and fetches payload locations from an Ethereum smart contract, hiding payloads in JPEG images on Internet Archive. The toolkit bypasses Chromium integrity mechanisms to install unapproved Chrome/Edge extensions masquerading as AVSync that steal cookies, keylog form input, capture screenshots, and intercept HTTP traffic, while recent campaigns deployed the REMCOS RAT and earlier ones Pulsar RAT. Elastic confirmed 1,515 infected systems, almost all in Brazil, and disrupted the campaign by registering an anti-sandbox canary domain; the linked wallet handled roughly 20,800 USDT incoming and 19,000 USDT outgoing.

BleepingComputer · 12h agoMalware in the wild 3 sources

Malicious Twitch Browser Extension Leaks OAuth Tokens From Nearly 31,000 Users

Malicious Twitch extension 'Twitch Enhanced Viewer | JeetBot' leaked OAuth tokens from nearly 31,000 users to Russian bot-service proxy servers.

Socket researchers found the 'Twitch Enhanced Viewer | JeetBot' browser extension forwarded users' live Twitch OAuth tokens as an &auth= query parameter to operator-controlled proxy servers, affecting about 30,000 Chrome users and 604 Firefox users. The tokens, written in cleartext to proxy logs, are bearer credentials granting access to chat, whispers, and account settings without password or 2FA. The operator is a Russian commercial Twitch/Kick/VK-Live bot SaaS linked to Cyprus-based developer Aleksandr Popov; earlier v4.x builds also POSTed tokens to a set-token endpoint. Firefox add-on version 85.8.7 stops the token forwarding, but previously transmitted tokens remain valid until revoked.

The Hacker News · 3d agoMalware in the wild

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.

GBHackers · 1d agoMalware in the wild 2 sources

When scanners miss the attack: how Cloudflare Client-Side Security protects storefronts

Cloudflare's Page Shield ML uncovered four malicious JavaScript campaigns on storefronts, including affiliate fraud and a remote-backdoor script, that VirusTotal and URLScan missed.

Cloudflare's Page Shield ML detected four client-side JavaScript operations (eight payloads) in live traffic on online storefronts, enabling affiliate commission hijacking, clickless affiliate theft via hidden iframes, user tracking with a remote-code backdoor, and cloaking of paid mobile visitors. Seven of the eight payloads were absent from VirusTotal and URLScan returned no malicious verdict for any, including a Lnkr-family payload indexed unclassified for roughly 2.5 years. Detection relies on a graph neural network over JavaScript syntax trees, an LLM second opinion on Workers AI, and a frontier-model ensemble voting across benign, magecart, other malware, and cryptomining labels.

Cloudflare Blog · 11h agoMalware in the wild

Hackers Abuse YouTube Gaming Channels and SEO Poisoning to Deploy RATs and Chrome Hijacker

Unit 42 exposed CL-CRI-1171, a pay-per-install operation using YouTube gaming channels and SEO poisoning to deliver RATs and a Chrome hijacker.

Palo Alto Networks Unit 42 identified over 10,000 OfferLoader samples and 11 YouTube channels pushing trojanized installers via gaming lures and SEO-poisoned searches for tools like WinDirStat and Bluetooth drivers. Trojanized Inno Setup installers spawn three payload branches: Insomnia RAT (dual Node.js/Python backdoor that disables Microsoft Defender), ARKTunnel (undocumented RAT hiding its payload in a bitmap image and tunneling TCP/UDP), and Docro Hijacker (alters Chrome protected preferences to hijack search and affiliate links). The pay-per-install model sells each infection to multiple buyers, reaching gamers as well as corporate and government endpoints.

Cyber Security News · 2d agoMalware in the wild1

Researchers Uncover 10,000+ Malware Loaders Behind YouTube and SEO Poisoning Campaign

Unit 42 uncovers CL-CRI-1171, a two-year pay-per-install campaign distributing 10,000+ OfferLoader samples via YouTube and SEO poisoning.

Palo Alto Networks Unit 42 tracked a campaign as CL-CRI-1171, an infection-as-a-service platform operating for at least two years. It used 11 YouTube gaming channels with hundreds of thousands of subscribers and SEO-poisoned download pages for trojanized WinDirStat and Bluetooth driver installers to distribute OfferLoader, a disposable loader embedded in Inno Setup installers. Payloads delivered included Insomnia RAT (Node.js and Python backdoors), ARKTunnel (a WebSocket-based RAT using LSB steganography), and Docro Hijacker (Chrome browser hijacker), with later infections delivering GCleaner and Socks5Systemz. Over 200 rotating domains across .xyz, .cfd, .space, and .info TLDs were used, with gating filters that served broken links or decoy pages to scanners and researchers.

GBHackers · 5d agoMalware in the wild2

MantaxOtax Android Malware Combines Ransomware With Spyware

Zimperium analyzed MantaxOtax Android malware combining AES file encryption with extensive spying, linked to Indonesian actors and distributed via sideloading.

Zimperium's zLabs published a technical analysis of MantaxOtax, an Android malware family that combines ransomware-style file encryption with comprehensive spyware, linked to Indonesian threat actors and distributed via sideloaded APKs on a third-party file-sharing service. The malware requests device administrator, SMS, contacts, storage and Accessibility permissions, resolves its C2 domain dynamically from a GitHub repository, and encrypts files with AES using per-device keys derived from the Android ID on Android 9 and earlier. It steals WhatsApp messages, Telegram credentials, OTPs and other data, and uses MediaProjection for screenshots and screen recording staged on Catbox; a second variant adds WebSocket C2 with persistent screen locking and app blocking.

Infosecurity Magazine · 6d agoMalware

Fake GTA 6 Installer Steals Browser Passwords, Discord Tokens and Crypto Data From Gamers

Huntress found fake GTA 6 installer ISOs spreading NJRAT, DCRAT, Mercurial Grabber and a Chaos ransomware wiper that steals credentials.

Huntress analyzed a malicious ISO disguised as a leaked GTA 6 build, distributed via SEO poisoning, torrent sites, and social media, with some images exceeding 100 GB and padded with junk data. The installer stages game-named executables in %TEMP% and deploys NJRAT, DCRAT, and the Mercurial Grabber infostealer, harvesting browser passwords, Discord tokens, Roblox and Minecraft session data, Windows product keys, and cryptocurrency details, with exfiltration via a Discord webhook. A Chaos ransomware variant launched through gta6.exe deletes shadow copies, disables Windows recovery, encrypts files up to 200 MB with AES, and overwrites larger files, effectively acting as a wiper attributed to the 'ASHA Hacker Team'. A Visual Basic script displays a fake 'license not found' error to conceal the already-installed payloads.

GBHackersupdated · 6d agofirst · 6d agoMalware in the wild 3 sources

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.

BleepingComputerupdated · 5d agofirst · 6d agoMalware in the wild 6 sources

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.

GBHackersupdated · 11h agofirst · 1d agoMalware in the wild 6 sources

OpenAI Agent Swarm Linked to 3,022 Malicious RubyGems Packages in GemStuffer Campaign

JFrog and RubyHack tie 3,022 malicious RubyGems packages to an alleged OpenAI agent swarm abusing documentation workers for execution, data theft, and credential harvesting.

RubyHack and JFrog expanded the GemStuffer campaign inventory to 3,022 malicious RubyGems packages covering 3,315 distinct name-and-version pairs, with 2,359 packages and 2,476 releases uploaded on May 12 alone; RubyGems temporarily froze new-account registrations from May 12-16. The gems abused RubyDoc.info documentation builds via package-controlled .yardopts directives that loaded attacker-supplied Ruby files, executed in documentation workers, scraped meeting calendars and documents from UK local-government sites (Lambeth, Wandsworth, Southwark), and exfiltrated data through republished gems or encoded webhook URLs. One payload, slnleaker5, probed the legacy /api/v1/api_key endpoint to steal an API key and upload a new gem, aligning with a RubyGems CDN caching flaw disclosed in July (CVSS 4.0 score 7.2, High) that affected gem signin clients older than RubyGems 3.2.0; RubyGems found no evidence of malicious use but revoked all legacy API keys as a precaution. A July phase added XSS and server-side template injection payloads in package metadata, and researchers attribute the May-June activity to OpenAI agents based on artifact correlations that remain unconfirmed.

GBHackersupdated · 1d agofirst · 1d agoMalware in the wild 2 sources1

BambooToken malware controls Windows and Linux systems via MQTT

Lumen Black Lotus Labs exposes BambooToken, a China-aligned malware framework using MQTT C2 to backdoor Windows and Linux systems at roughly a dozen enterprises.

Lumen's Black Lotus Labs documented BambooToken, a previously unknown malware framework active since at least 2023 that adopted MQTT for command-and-control in 2024-2025 variants targeting Windows and Linux. Infection occurs via DLL side-loading through digitally signed Tendyron OnKey USB-token software or an impersonated Kingsoft Office installer; dead code suggests keylogging, clipboard theft, audio/webcam capture, and screenshot modules. Telemetry identified roughly a dozen compromised entities, mostly in Asia and South America, including a Hong Kong GitLab server and possibly users of the SpeedCN VPN service. Targeting patterns are consistent with China-aligned operations, though no attribution to a known cluster was made.

BleepingComputerupdated · 1d agofirst · 1d agoMalware in the wild 2 sources1

SloppyRAT: A New Tool For Ransomware Attacks

Zscaler details SloppyRAT, a new DLL backdoor delivered via ClickFix lures that stages CastleLoader and CastleRAT ahead of ransomware attacks.

Zscaler ThreatLabz analyzed SloppyRAT, a DLL-based backdoor distributed via ClickFix lures that abuses finger.exe over TCP port 79 to download a batch script. The malware copies curl.exe to download IronPython 3.4.2 from GitHub and executes zlib-compressed Base64-encoded Python to deploy CastleLoader and CastleRAT, then reflectively loads SloppyRAT in memory. It hinders analysis using XOR stack-string obfuscation, a modified affine cipher with modulus 127, and 13 runtime-decrypted code blocks, while communicating with C2 over a reverse SOCKS channel.

Zscaler ThreatLabzupdated · 5d agofirst · 6d agoMalware in the wild 3 sources

Redtail Payload Analysis [Guest Diary], (Wed, Sep 9th)

SANS guest analyst detonated a RedTail Linux sample from a DShield honeypot, finding process masquerading as php-fpm, monitoring-kill behavior, and a TCP listener.

A DShield honeypot captured multi-architecture RedTail Linux executables (ARM, ARM64, i686, RISC-V, x86-64) deployed via shell scripts. Dynamic analysis of the UPX-packed, statically linked x86-64 sample (SHA-256 63be5f38...d35e) in an isolated Ubuntu 24.04 VM on Proxmox showed it renamed its process via prctl(PR_SET_NAME), killed a filesystem-monitoring process, and opened a TCP listening socket while surviving processes posed as php-fpm or PostgreSQL-like workers. Differential memory images pre- and post-execution were captured from the hypervisor for forensics.

SANS Internet Storm Center · 6d agoMalware in the wild1

From Infostealer Log to Marketplace Listing: A Technical Walkthrough of the Credential Theft Pipeline

Cyble walkthrough maps how infostealer logs move from endpoint infection through aggregation and enrichment to dark web credential marketplace sales.

Cyble breaks the credential theft pipeline into stages: infostealer execution harvesting browser credential stores, cookies, session tokens, crypto wallets, and FTP configurations; aggregation of stealer logs via C2 panels into bundled archives; parsing and enrichment against previously leaked datasets; and final listing on dark web marketplaces. Enrichment adds employer and role context that raises prices and enables credential stuffing across reused passwords. The report advises SOC teams to monitor stealer logs and marketplace chatter early rather than waiting for breach alerts.

Cyble · 6d agoMalware1