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 4.0 macro-enabled workbook. Static analysis revealed an Auto_Open defined name, which is a common technique for automatic execution upon opening. The critical heuristic firings indicate the use of dangerous formula APIs, specifically the RUN function, which is used to execute arbitrary commands. The script attempts to construct a string using CHAR functions and then executes it via the RUN function, indicating it's likely a downloader for a second-stage payload.
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.txt17446cc3b799fe5d5bfcdd94846daf25c2bec159441e88df056f2e7e825fb9af |
xlm-macro | oletools.olevba.extract_all_macros (XLM macro listing) | 128366 bytes |
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