Office (OLE) / .XLSX malware analysis — malicious · 7c6b0d88df2915cf

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-27 11:47:15 Authoring application: Microsoft Excel

MD5: 23e06bba24fecd79fac09e2535493ad9 SHA-1: 7e50de3f1edaf022bf81a696b07c87eb23d76d49 SHA-256: 7c6b0d88df2915cf7a865840b9ac4f78f69b0ecc19fb343a9e5e07cd504f6cd7

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications T1059.001 PowerShell

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. The presence of dangerous formula APIs like RUN further supports this. While the exact payload is not immediately clear from the truncated script, the Auto_Open function is designed to execute code upon opening the workbook, likely leading to further stages of infection.

Heuristics 3

Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME

oletools 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.
XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN

Excel 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.
Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN

Workbook 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.txt` `f53e330c755352b99b0d8ddaab13cf2ed21d31ae82b8e648765bb63ed793e16e`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6828 bytes

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