Office (OLE) / .XLSX malware analysis — malicious · cc4c3f46f23b68a8

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:38:31 Authoring application: Microsoft Excel

MD5: ca9c6a34630c02ab961238de29cfe49b SHA-1: 29794862e6ee179cfc82e836ca7f1dd5784deb39 SHA-256: cc4c3f46f23b68a8289cc44c5f87b623e50556fe4b10a6e3ffb54f3e56fd3b1b

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell

The sample contains critical heuristic firings indicating the presence of Excel 4.0 macros, specifically an Auto_Open defined name that utilizes dangerous formula APIs like RUN. This suggests the macro is designed to execute arbitrary commands upon opening the spreadsheet. No specific URLs or hashes were extracted, but the presence of the Auto_Open macro strongly implies a malicious intent to download and execute a secondary 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` `773a1704f81397093d986ad2b90c3040f59fa78cddf43efdd47efcc9c27bd012`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6855 bytes

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