MALICIOUS
120
Risk Score
Malware Insights
MITRE ATT&CK
T1059.005 Visual Basic
T1204.002 Malicious File
T1105 Ingress Tool Transfer
The sample is an Excel 4.0 macro sheet that contains WinAPI strings indicative of downloading and executing a payload. Specifically, it uses URLDownloadToFileA to download a file to C:\Users\Public\biwa\wd.exe and then ShellExecuteA to run it. The macro sheet also calls CreateDirectoryA, suggesting it may create the target directory first. The confidence is high due to the clear WinAPI calls and reconstructed paths.
Heuristics 2
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Excel 4.0 macro sheet (1 sheet(s)) critical OOXML_XLM_MACROSHEETSpreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.
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Binary XLM macro sheet with WinAPI/download strings critical OOXML_XLM_BINARY_WINAPI_STRINGSExcel 4.0 macro sheet is stored as BIFF12/XLSB binary data and contains Win32 download or process-execution API strings such as URLDownloadToFileA, ShellExecuteA, or CreateDirectoryA. These strings are high-signal in XLM macro sheets and catch payload-download macros that XML-formula scanners cannot parse.
Extracted artifacts 1
Files carved from inside the sample during analysis.
| Filename | Kind | Source | Size |
|---|---|---|---|
xlm_sheet_00.bin48b4a21f59f559c68e5891e71760d266cc3eba7f907103c4042d5d9b3b02c484 |
xlm-macrosheet | OOXML XLM macro sheet: xl/macrosheets/sheet1.bin | 5255 bytes |
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