Fake Claude Opus 5 app delivers malware and wipes its own tracks
A fake 'Claude Opus 5' GitHub repository impersonating Anthropic distributes RevStealer, a Windows infostealer stealing passwords, crypto wallets and VPN credentials.
Morphisec identified a malicious GitHub repository, Claude-Opus-5-Free-Desktop, impersonating Anthropic to distribute a roughly 101 MB download that launches RevStealer, a Windows information-stealing malware. The malware targets browser credentials, Windows Credential Manager, a dozen password managers, more than fifty cryptocurrency wallets, VPN, messaging, game launcher and streaming accounts, streaming stolen data to its server before deleting itself. It evades analysis with ten sandbox and VM checks, indirect system calls, Windows Defender exclusions, a fake verification window, and a Polygon blockchain smart contract fallback for C2. Only 1 of 66 antivirus engines flagged the sample at check time.
AsyncRAT Malware Abuses AutoIt and PowerShell to Hide Inside Legitimate Windows Process
Point Wild details a five-stage AsyncRAT campaign using AutoIt abuse and process injection to hide a .NET RAT inside Microsoft's signed charmap.exe.
Researchers at Point Wild Threat Intelligence analyzed a campaign starting from a lure batch file ('Right-click to open Invoice Details.bat') that launches hidden PowerShell to reconstruct a Base64/XOR-obfuscated payload. The stage drops a renamed signed AutoIt interpreter and loader script into %LOCALAPPDATA%\Temp and achieves persistence via a batch file in the user's Startup folder (T1547.001). The loader decrypts the payload in memory with single-byte XOR key 0x36 and injects it into SysWOW64\charmap.exe using OpenProcess/VirtualAllocEx/WriteProcessMemory/CreateRemoteThread, with PE-sieve confirming an in-memory implanted PE and patched AMSI modules. The final AsyncRAT payload performs screen capture and data theft, with observed C2 at 158[.]51[.]122[.]136:4944 over raw TCP.
Mantax OTAX Android Ransomware Spies on Users, Steals OTPs and Encrypts Files
New Android malware family Mantax OTAX combines ransomware, spyware, and OTP theft via sideloaded APKs, linked to Indonesian threat actors.
Researchers at zLabs and Zimperium analyzed Mantax OTAX, an aggressive Android malware strain distributed as sideloaded APKs through phishing and messaging lures on third-party file-sharing services. The malware requests device-administrator and Accessibility permissions to steal lock-screen PINs, intercept SMS one-time passwords, harvest contacts and history, capture screens via MediaProjection, and silently photograph victims, while encrypting files with AES and writing .enc files on Android 9 and older. Its C2 uses HTTPS at apimantax[.]otax[.]fun with the active domain fetched dynamically from a GitHub repository, and a newer version adds WebSocket communication, app blocking, video overlays, and text-to-speech harassment. A Firebase misconfiguration exposed extortion conversations and victim data, and Android 10+ Scoped Storage limits the encryption reach but not the surveillance capabilities.
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.
ValleyRAT: When Legitimate Software Becomes a Malware Delivery Tool
Kaspersky details ValleyRAT delivered via trojanized QN Wallpaper using DLL sideloading, tied to Silver Fox and hitting 1,500+ users in China and India.
Kaspersky found a malicious installer abusing a modified version of the legitimate QN Wallpaper adware application to deliver the ValleyRAT backdoor via DLL sideloading of libcef.dll. The installer masquerades as DingTalk, Chrome or Tencent Meeting software, creates persistence, disables Windows Defender via the DisableAntiSpyware registry key, and loads AES-encrypted payloads. ValleyRAT collects keystrokes, clipboard contents and screenshots plus system details, can download additional modules, and resists removal by injecting into svchost.exe or marking its process critical. The campaign was detected over 100,000 times in 2026, affecting more than 1,500 users mainly in China and India, and is attributed to Silver Fox with both espionage and financial motives.
GoCaracal Malware Uses Ethereum Smart Contract to Fetch Replacement C2 Address
Arctic Wolf links new Go-based GoCaracal malware with Ethereum smart-contract C2 fallback to Dark Caracal, targeting a Venezuelan communications organization.
Arctic Wolf assessed with medium confidence that a June 2026 intrusion at an unnamed Venezuelan communications organization used GoCaracal, a previously undocumented Go-based malware framework linked to Dark Caracal. The lightweight profile provides encrypted C2, interactive shell access, and shellcode injection; the extended profile adds browser data theft, keylogging, WebRTC remote desktop, and SOCKS5 proxying. When the primary C2 server is unreachable, the malware queries an Ethereum smart contract via eth_getStorageAt at public JSON-RPC endpoints to fetch a replacement C2 address. Bandook was deployed in parallel, and Arctic Wolf published a YARA rule and indicators of compromise.