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

Static analysis result for SHA-256 671b853a19abc751…

MALICIOUS

Office (OLE) / .XLSX

37.0 KB Created: 2020-11-27 11:43:18 Authoring application: Microsoft Excel
MD5: 94683d35640f949603cbc466379807b0 SHA-1: beac4d49cc76f1aa5ac4b428c20f8b3afd4d7c92 SHA-256: 671b853a19abc7516c70d8d45b99c26db9bd9fb6ea87c6138ea70dd87a090a72
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. The presence of dangerous formula APIs further supports this. The macro sheet is configured to automatically execute upon opening, likely to download and run 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.

FilenameKindSourceSize
xlm_macros.txt
0eca734a6b83e477794e1719a87df6f403a93fba457f89025a21f17498254ddb		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6883 bytes

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