Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 d1df92c14e44c682…

MALICIOUS

Office (OLE) / .XLSX

41.0 KB Created: 2020-11-13 16:17:23 Authoring application: Microsoft Excel
MD5: c3d706e261bc1d117d995eb4e5abb2e4 SHA-1: 43e00b6a0c4e15c1cd47af2285aec096e8e79908 SHA-256: d1df92c14e44c6823e8f30e6991b202506c2bad55ca3c3001ee822686fba49d4
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. The presence of dangerous formula APIs, including the 'RUN' function, indicates the macro is designed to execute arbitrary commands. This is a common technique for initial payload delivery in macro-based attacks.

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.

FilenameKindSourceSize
xlm_macros.txt
451d6f0a92c4570dba03584679d157ef5950df0b95e97d4ed7d6c432baa09a5d		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9594 bytes

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