Office (OLE) / .XLSX malware analysis — malicious · 3ea2e1259ed1909e

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:40:51 Authoring application: Microsoft Excel

MD5: d03047f37c931684987976f1f34129ab SHA-1: 5ab6fcfc5acc82e9a62cc44cf5aa64d12877d937 SHA-256: 3ea2e1259ed1909ee18fdd85eb0e8f3a724586b160495bc283c2fbce0beb50d0

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates the macro sheet is designed to automatically execute code upon opening. The presence of dangerous formula APIs like RUN further confirms the malicious intent to execute arbitrary commands. While no specific URLs or hashes were extracted, the mechanism itself is a high-risk attack vector.

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` `8228b68333bf941fc90f2c1e614e1f5ec36f6f7edb332a06a10610028cce2431`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6604 bytes

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