Note: this report may be incomplete because the AI analysis reached the following limit(s): token. Summary 1. Generic info: The sample `3c47eccd8fc8d9a9ce087c5ff5f9dce08d5dd15123b84a44301ca98b6a4f797d` (#AID=163#) is a 32-bit Windows PE executable. Metadata indicates it was compiled using MSVC 2022 and the Rust programming language, with the debug path set to `wallpaper_manager.pdb`. The file features an appended overlay with high entropy (186) starting with the ASCII magic `CRYPTED_`. 2. Inferred behavior: The executable acts as a loader or a compromised utility application. Its main goals are to establish system persistence and to execute a secondary process or command. It leverages `%LOCALAPPDATA%` paths, invokes `cmd.exe` to run a dynamically built command that registers itself into the Windows startup sequence (`HKCU\...\Run`), and decodes embedded data structures (including Base64 strings and encrypted payload blocks) likely used for configuration or dropping a secondary stage. 3. Sub-files: Analysis of the PE resources found only standard icon files (`ICO/1/unk` to `ICO/9/unk` and `GRPICO/ICON207/unk`), which are standard for a GUI application. No secondary executables, scripts, or archives were detected within the PE sections. 4. IOCs: - **Registry Key**: `HKCU\Software\Microsoft\Windows\CurrentVersion\Run` - **Paths**: `C:\Windows\Temp\WindowsMedia`, `%LOCALAPPDATA%\Microsoft\WindowsMedia` - **Executed Binary**: `cmd.exe` 5. Key detections: - **YARA Rules**: Triggered `AutorunKey` (persistence), `RunShell` (lateral movement/execution), and the Rust compiler signature. - **Anomalies**: `DynamicString` construction, `HugeStringBase64`, `XorInLoop` (decryption routine), `InvalidChecksum`, `StackArrayInitialisationX86` (common in string/decoder implementations), and `UnknownOverlayMediumToHighEntropy`. - **Code**: Decompilation of function `sub_401330` reveals hardcoded strings formatted exactly as command-line arguments (`regaddHKCU...\Run/v/tREG_SZ/d/f`), combined with Base64 decoding logic to obfuscate the executed payload. Evidence The file's behavior pivots around a high-scoring string at offset 0xb19333 containing a concatenated command: `reg add HKCU\Software\Microsoft\Windows\CurrentVersion\Run /v /t REG_SZ /d /f`. This string is heavily cross-referenced by the main execution routine `sub_401330`. Alongside this, the binary features multiple hardcoded Base64 blobs (e.g., `mKioqK/uXl5v7j+...` at offset 0x4133C0) and an encrypted overlay (`CRYPTED_` at offset 0x75B700) typical of droppers that extract payloads at runtime. Counter arguments The automated Kesakode engine yielded very low threat scores (Max 18/100 for DustyHammock), indicating a lack of matches against known malware families. Furthermore, the PDB file `wallpaper_manager.pdb` strongly implies this is a legitimate (albeit possibly pirated, modified, or adware-driven) desktop customization tool. Many legitimate freeware installers or "cracked" software utilities incorrectly flag for persistence because they automatically set themselves to launch at startup to display wallpapers or animations. Verdict **SUSPICIOUS / POTENTIALLY MALICIOUS (Confidence: 60/100)** While the file may legitimately be a wallpaper manager, the presence of dynamic command construction using `cmd.exe`, the `CRYPTED_` executable overlay, and complex XOR/Base64 decoding routines heavily deviate from standard benign software practices. It is highly likely a trojanized utility, a cryptominer, or an installer for Potentially Unwanted Programs (PUP).