typeentityconfidencemediumcreated2026-06-22updated2026-06-22dotnetevasionmalware-family

unclassified-dotnet-minesweeper-masquerade

Overview

A .NET Framework 4.0 WinForms executable presenting a fully functional Minesweeper game, distributed under business-document filenames (AWB_411744484099.exe). The binary contains auto-generated TypedDataSet classes, game board bitmap assets, and standard WinForms event handlers. No malicious behavior is observable statically. OpenCTI's remcosrat label for the first observed sample (c59a535b) is a confirmed false positive.

Build Stack

  • Language / runtime: C# targeting .NET Framework 4.0 (CLR v4.0.30319)
  • Compiler: Microsoft C# compiler (csc.exe / MSBuild) with Visual Studio dataset designer
  • Packaging: Plain PE32, 3 sections (.text, .rsrc, .reloc); no packer, no obfuscator
  • Anti-analysis: None (no debugger checks, no VM detection, no sandbox evasion)
  • Embedded resources: PNG game board graphics, RT_VERSION with fabricated Microsoft Corporation. identity, RT_MANIFEST

Deploy / TTPs

  • ATT&CK: None confirmed statically. Capa flags T1620 and B0013.001 are benign .NET runtime artefacts.
  • Persistence: None observed
  • C2 / exfiltration: None observed — no System.Net, Socket, WebClient, or mail APIs
  • Lateral movement: None observed
  • Masquerade technique: Airway-bill filename (AWB_*) + Microsoft Corporation. version-info mismatch against a Minesweeper game

Variants / Aliases

  • Primitive Queue (product name from version info)
  • SpQF.exe (internal name / PDB)
  • OpenCTI false label: remcosrat

Notable Analyses

  • c59a535b — Full static deep-dive with .NET metadata extraction, false-positive family attribution analysis, and YARA rule. No CAPE detonation (no Windows guest). ^[/intel/analyses/c59a535b1a8525c8f5714034085bfa0008e5c4bb55f0c39183c07ac3828a7cdd.html]

Capabilities

  • dotnet-winforms-gui-masquerade
  • microsoft-version-info-forgery
  • airway-bill-filename-social-engineering
  • typeddataset-auto-generated-bloat
  • no-network-api-surface
  • no-persistence-mechanism
  • no-packing-no-obfuscation

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