Office (OLE) / .XLSX malware analysis — malicious · 8dca64cd407c4a01

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:39:03 Authoring application: Microsoft Excel

MD5: 2374473139a7ffab384f35582ea5fe11 SHA-1: da5486856201adf264d19b8c3ba5dc48966a3272 SHA-256: 8dca64cd407c4a018dc60c6522490349ef8087cd8a4f7dc6bd50c3e4e21a5297

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. The presence of dangerous formula APIs like RUN indicates that the macro is designed to execute arbitrary commands. This is a common technique for initial execution and payload delivery.

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` `d19e33615a2465a34c257a0a57b16d8e5cda79338885a4e53994adae53a39f3f`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6720 bytes

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