MALICIOUS
140
Risk Score
Malware Insights
MITRE ATT&CK
T1059.005 Visual Basic
T1059.001 PowerShell
T1059.003 Windows Command Shell
The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open defined name. This indicates the workbook is configured to automatically execute a macro when opened. The critical heuristic 'OLE_XLM_DANGEROUS_FN' with 'risky-formula=3; RUN=0' confirms the use of the RUN function, which is highly suspicious as it can be used to execute arbitrary commands. The macro sheet itself contains obfuscated data, suggesting an attempt to hide malicious activity. The primary IOC is the use of the RUN function within the Auto_Open macro.
Heuristics 3
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Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAMEoletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
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XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FNExcel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
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Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPENWorkbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
Extracted artifacts 1
Files carved from inside the sample during analysis.
| Filename | Kind | Source | Size |
|---|---|---|---|
xlm_macros.txt46f1e477db6db30a42fda36e23b7b9956b574fff81cb258e8b8e11568eb3b496 |
xlm-macro | oletools.olevba.extract_all_macros (XLM macro listing) | 6635 bytes |
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