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.
JSCeal Hides Crypto Malware in V8 Bytecode
Check Point details JSCeal, a crypto-stealing malware delivered as compiled V8 bytecode, and built a decompiler pipeline to expose its capabilities.
JSCeal, tracked by Check Point Research since early 2025, is a cryptocurrency stealer delivered as heavily obfuscated JavaScript compiled to V8 bytecode (.jsc) and run by a bundled Node.js runtime. Check Point, presenting at Black Hat USA 2026, extended the open-source View8 decompiler into a pipeline that recovered readable code from 23 samples, revealing theft of browser credentials and cookies, Telegram sessions, keystrokes, screenshots, HTTPS traffic interception with attacker-controlled certificates, and automated Google account takeover. Targeted overrides rewrite content for Binance, Bybit, and Ledger users. Later samples added AES-256-CBC encryption with externally supplied keys and expanded targeting to macOS.
FrostyGoop’s Zoom-In: A Closer Look into the Malware Artifacts, Behaviors and Network Communications
Unit 42 dissects FrostyGoop OT malware, which sent Modbus TCP commands to disrupt heating for 600+ apartment buildings in Ukraine.
Palo Alto Unit 42 analyzed new FrostyGoop/BUSTLEBERM samples, the ninth known ICS-centric malware, first used against a Ukrainian municipal energy company by sending Modbus TCP commands to ENCO control devices. The attack caused a two-day heating outage affecting over 600 apartment buildings during sub-zero temperatures. The Go-compiled malware accepts Modbus register operations and timing parameters via command-line arguments or a JSON configuration file, uses an obscure open-source Modbus library, and checks the Windows BeingDebugged flag to evade debuggers. Unit 42 telemetry recorded over 1 million Modbus TCP devices exposed to the internet between September and October 2024.
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.
New SLEEPWALKER Backdoor Waits for One Crafted Packet, Then Runs Its Own Bytecode
A new Windows backdoor dubbed SLEEPWALKER hides as ESET Management Agent's dpapi.dll, waits for a crafted network packet, then executes custom 23-instruction bytecode.
Researcher Dominik Reichel documented SLEEPWALKER, an unsigned 59,904-byte 64-bit Windows DLL that side-loads into ESET Management Agent's ERAAgent.exe while impersonating dpapi.dll. The implant monitors every network interface indefinitely for a specifically crafted trigger packet, then executes commands written in a custom 23-instruction bytecode language over six transports, including TCP, UDP, ICMP, SMB named pipes, raw promiscuous capture, and VMware VMCI. It has no embedded infrastructure, makes no outbound connections of its own, and requires prior local administrator access to install; no victims, attribution, or in-the-wild deployment are confirmed. Reichel assesses the design as consistent with a targeted, well-resourced operation, while ESET calls the scenario's security relevance negligible since it provides no new access path.
Exploring the Latest Mispadu Stealer Variant
Unit 42 found a new Mispadu infostealer variant targeting Mexican users via malicious .url files exploiting the SmartScreen CVE-2023-36025 bypass.
Unit 42 discovered a new variant of Mispadu Stealer, a Delphi-based banking trojan first reported in 2019, found while hunting for the Windows SmartScreen bypass CVE-2023-36025. The campaign uses crafted .url files referencing UNC network-share paths with an HTTP port (@80) that forces payload retrieval over WebDAV via rundll32.exe, avoiding SmartScreen warnings. Analyzed samples (~4 KB, compiled 2023-11-12) predate the CVE publication, and ZIP payloads were likely distributed as email attachments, primarily targeting users in Mexico.