Office (OLE) / .XLSX malware analysis — malicious · 1613db48a8fe8365

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:42:58 Authoring application: Microsoft Excel

MD5: de1259bd4a4db4a927c15ee2a0d37441 SHA-1: 05963b426d412a4f3e66f45bbda5571ce9869321 SHA-256: 1613db48a8fe83658e17fdb2284b38bdaf09b9bca03becdd2e071274ab2bbf4f

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates that the macro will execute automatically when the workbook is opened. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary commands, likely to download and run a second-stage 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` `bcf4b286ba9417d13aebb7dd323a19575a09502743635dc08fcf1fbca457ec49`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6568 bytes

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