Office (OLE) / .XLSX malware analysis — malicious · 010dcbd7cb1f528d

MALICIOUS

Office (OLE) / .XLSX

35.5 KB Created: 2020-11-25 10:43:54 Authoring application: Microsoft Excel

MD5: ac982aad1a84bfdef5a995a77f4a26fb SHA-1: d8f46de1b10f575b1999885950b11ff87a39d2f2 SHA-256: 010dcbd7cb1f528d90281415a268cb0c6fb87cd65348edb31246a31d71fc9276

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1566.001 Spearphishing Attachment

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, specifically utilizing dangerous formula APIs like RUN. This strongly suggests the macro is designed to execute arbitrary code upon opening the spreadsheet. While no specific URLs or commands were directly extracted, the presence of the Auto_Open function points to a downloader or initial execution stage for a malicious payload.

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` `fbf6cef1b8cc79eee27622e76ae2250dab3fa5780d5ab11cb28e97ea4401f2f5`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6288 bytes

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