FortiGuard Labs observed a multi-stage Windows intrusion that used AI-themed lures, hidden files inside archives, and staged scripts to deploy AutoHotkey loaders, .NET payloads, AsynRAT, and a modular RAT. The campaign used disguised Realtek and Microsoft Windows artifacts, persistence via scheduled tasks and VBS, and command-and-control infrastructure including 107[.]172[.]10[.]190 and the domains shampobiskworld[.]nl, shampoolagtto[.]com, and shamppocosmaticso[.]com. #AsynRAT #AutoHotkey #RealtekAudioService64 #CheckRealtekAudioVersion #ResetRealtekAudioSettings64 #10717210190
Keypoints
- The attack began with malicious archives and LNK shortcuts disguised as AI-related technical documents.
- Hidden files inside the archive were used as multi-stage payload containers, with scripts extracting specific line ranges to reveal the next stage.
- PowerShell was heavily obfuscated, used hidden execution, and decrypted embedded content into scripts and staged components.
- The malware established persistence through scheduled tasks and later added VBS-mediated task chains and environmental repairs for script execution.
- AutoHotkey was abused as an execution engine, while recovered components led to process hollowing and in-memory .NET payload loading.
- The final payload was a modular RAT capable of remote desktop, screenshot capture, mouse input simulation, self-update, self-delete, and encrypted C2 communication.
- Indicators and infrastructure included the IP 107[.]172[.]10[.]190, multiple Shampoo domains, and malware components associated with AsynRAT and a clay_Client RAT.
MITRE Techniques
- [T1204.002 ] User Execution: Malicious File â The victim had to open a shortcut inside a disguised archive to start the infection chain (âOnce the victim opens the LNK file, the shortcut executes an obfuscated command sequenceâ).
- [T1059.003 ] Command and Scripting Interpreter: Windows Command Shell â The LNK used cmd.exe and related native commands to extract and run staged content (ânative Windows components such as cmd.exe, more, type, and findstrâ).
- [T1059.001 ] Command and Scripting Interpreter: PowerShell â Multiple stages used PowerShell to decode, decrypt, drop, and execute payloads (âThe PowerShell stage is invoked with â-windowstyle hiddenâ⌠and â-ExecutionPolicy Bypassââ).
- [T1027 ] Obfuscated Files or Information â Payloads and commands were concealed through hidden attributes, Base64, hex, runtime decoding, and variable reconstruction (âhidden filesâ, âBase64-encoded stringsâ, âreconstructed at runtime from character arraysâ).
- [T1140 ] Deobfuscate/Decode Files or Information â The malware decoded Base64, hex, and GZip-compressed data into runnable scripts and executables (âdecodes it from Base64â, âconverts the result back into bytesâ, âopens the previously dropped Subtitles file as a GZip-compressed streamâ).
- [T1027.013 ] Binary Padding / File Masquerading â Files were disguised as PDFs, assets, manifests, and Realtek components to hide malicious content (â3th.pdfâ, âRealtekAudioService64.ps1â, âRtkLoggingManifest.manâ).
- [T1564.001 ] Hide Artifacts: Hidden Files and Directories â The archive contained hidden files intended to evade casual inspection (âtwo other files named 3th.pdf and 4th.pdf with a Hidden attributeâ).
- [T1053.005 ] Scheduled Task/Job: Scheduled Task â Persistence was established with multiple scheduled tasks and triggers (âregistering a scheduled task named CheckRealtekAudioVersionâ, âregisters two scheduled tasksâ).
- [T1546.003 ] Event Triggered Execution: Windows Management Instrumentation Event Subscription â Not mentioned.
- [T1112 ] Modify Registry â The 32-bit script re-enabled Windows Script Host and restored file associations by editing the registry (âchecks whether Windows Script Host has been disabled in the registry, re-enables it if necessaryâ).
- [T1562.001 ] Impair Defenses: Disable or Modify Tools â Defender exclusions were added to weaken host defenses (âadding C: to Microsoft Defenderâs exclusion pathsâ).
- [T1105 ] Ingress Tool Transfer â Additional payloads were retrieved and written to disk from embedded containers and later stages (âextracting ⌠dataâ, âdrops a newly received payload binary into the %TEMP% directoryâ).
- [T1055 ] Process Injection â The .NET loader performed process hollowing into legitimate .NET processes (âcreates a legitimate .NET process in a suspended stateâ, âallocates memory within the remote processâ).
- [T1047 ] Windows Management Instrumentation â The final RAT queried system information such as win32_processor and Win32_Processor.deviceid (âextracts basic information from victimsâ).
- [T1218.007 ] System Binary Proxy Execution: Mshta â Not mentioned.
- [T1021.001 ] Remote Services: Remote Desktop Protocol â The RAT included remote desktop capabilities (âRemoteDesktopOpenâ, âRemoteDesktopSendScreenâ).
- [T1106 ] Native API â The injection chain relied on Windows APIs such as CreateProcess, GetThreadContext, WriteProcessMemory, VirtualAllocEx, ZwUnmapViewOfSection, SetThreadContext, and ResumeThread (âThe underlying API calls follow a classic injection sequenceâ).
- [T1027.005 ] Protocol Obfuscation â The malware encrypted serialized traffic using RijndaelManaged and custom length headers (âencrypting them using RijndaelManaged in ECB modeâ).
Indicators of Compromise
- [IP address ] C2 infrastructure used by the final RAT â 107[.]172[.]10[.]190
- [Domains ] C2 domains used after deobfuscation â shampobiskworld[.]nl, shampoolagtto[.]com, and other 1 item
- [File names ] Staged files and disguised payload containers â Agentic Coding with Claude Code, 3th.pdf, and other 4 items
- [File names ] Dropped scripts and loaders in the Realtek-themed chain â RealtekAudioService64.ps1, RealtekAudioService64.bat, and other 6 items
- [File hashes ] Fortinet-reported malware component hashes â LNK61b7fa5a7186cbf73dbc1f03e6e6f6819f5eb1e630a001059d381114bda2f974, POWERSHELL7d6ee3c6ff8f70b1817aaec82aff1d2babe0b62cafef3975262644743afc0cb8, and other 1 item
- [Scheduled task names ] Persistence artifacts created on victim systems â CheckRealtekAudioVersion, RealtekAudioEnhancements64, and other 1 item
- [Mutex ] Anti-duplicate execution marker used by final RAT â IDG5FUAM3PSONBSInGIGSWSD