Office (OLE) / .XLSX malware analysis — malicious · 949e74b03484fc11

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-25 10:46:24 Authoring application: Microsoft Excel

MD5: f9f434fde2dda66b73a2851ad03c6ba1 SHA-1: a906a40ab47232a094fa7486e680862d2077de7e SHA-256: 949e74b03484fc11f9e3a4db226d48994524d7fb262a857862644b2f880bd190

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications 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 indicator of malicious intent. The presence of the 'RUN' function within the macro sheet suggests an attempt to execute arbitrary commands. While the exact payload is not discernible from the provided evidence, the mechanism points to a macro-based execution of 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` `d1696c0a475c3c8793223e11c750f41a91e320c07b6ca05e2ef9529384ee30ca`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6419 bytes

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