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Four REVSTEALER-Linked Modules Disable Windows Update and Defender to Run a Crypto Miner
Elastic documents four persistent REVSTEALER-linked tools (ProManager, WinUpdate, SoftManager, LockAppHost); LockAppHost disables Windows Update and Defender to run a crypto miner.
Elastic Security Labs identified four previously unreported executables tied to REVSTEALER, a commercial Windows infostealer sold since at least February 2026: ProManager, WinUpdate, SoftManager, and LockAppHost. LockAppHost abuses CMSTP for elevation, adds Microsoft Defender exclusions, disables five Windows Update services and 13 scheduled tasks, then hides a miner in legitimate Windows processes; other modules steal wallets, clipboard-swap crypto addresses, and turn victims into reverse proxies. The components share REVSTEALER tradecraft including packer, runtime function resolution, and Polygon smart-contract backup configuration (EtherHiding). Elastic's detection rule matched about 4,700 VirusTotal samples over the past year; distribution uses hijacked YouTube channels promoting game cheats and a fake 'Claude Opus 5 Free Desktop' app.
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KREMLIN Banking Malware Hijacks Chrome and Edge to Steal Credentials and Session Tokens
Elastic Security Labs details KREMLIN, Brazilian banking malware using malicious Chrome/Edge extensions and Ethereum smart contracts to steal credentials and session tokens.
Elastic Security Labs documents KREMLIN (tracked as REF9334), a Brazilian banking malware toolkit active since at least May 2025 that impersonates a dozen Brazilian banks. It uses multi-stage JavaScript loaders, a C++ installer that DLL-sideloads via a legitimate SentinelOne binary, and a malicious Chrome/Edge extension named 'AVSync System Inc.' Ethereum smart contracts act as dead-drop resolvers for C2 endpoints, a shift that occurred May 19, 2026, making infrastructure hard to disrupt. The extension harvests cookies, sessionStorage/localStorage, browsing history, screenshots, and full page HTML via WebSocket plus CSS-disguised polling endpoints. The group has run seven distinct campaigns and also distributes Pulsar RAT and Remcos RAT.
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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.
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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.
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KREMLIN Banking Malware Infects Over 1,500 Systems With Malicious Chrome Extension
Elastic tracks KREMLIN banking malware that used fake Brazilian bank JavaScript lures to deploy malicious Chrome and Edge extensions on 1,515 systems.
Elastic researchers tracked the KREMLIN banking malware operation across seven campaigns over 15 months, infecting 1,515 systems, 98.75% of them in Brazil. Portuguese-language lures posing as bank records and invoices deploy a hostile 'AVSync' extension into Chrome and Edge profiles that harvests passwords, session cookies, keystrokes and screenshots. Loaders check for sandboxes, create scheduled tasks and fetch fresh infrastructure from an Ethereum smart contract; a network canary takeover temporarily disrupted infections.
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