MALICIOUS
140
Risk Score
Malware Insights
MITRE ATT&CK
T1059.005 Visual Basic for Applications
T1566.001 Spearphishing Attachment
The critical heuristics indicate the presence of obfuscated Excel 4.0 macros with an Auto_Open execution chain. The macro code uses a series of `FORMULA(CHAR(...))` calls, which are heavily obfuscated and likely intended to construct and execute a command to download and run a second-stage payload. The specific formulas are too complex and truncated to reconstruct the exact command or URL, but the overall pattern suggests a downloader or initial access mechanism.
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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Obfuscated XLM Auto_Open execution chain critical OLE_XLM_OBFUSCATED_AUTOEXEC_CHAINExcel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and an obfuscated formula execution chain. The macro builds strings through FORMULA(CHAR(...)), primes state with SET.VALUE / GET.CELL / GOTO, and transfers control through RUN(). This is a high-confidence XLM malware pattern.
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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.txt04611b9093c8f3c3aaf744dff9c5f91966aefccee40560e874604a4ace66e8fc |
xlm-macro | oletools.olevba.extract_all_macros (XLM macro listing) | 129419 bytes |
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