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

Static analysis result for SHA-256 54016c342dd2cd52…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:40:32 Authoring application: Microsoft Excel
MD5: 03ada097447e617decfd37df2577e610 SHA-1: d949f8765e03008b36d2857c16dc707f4ba8d5a4 SHA-256: 54016c342dd2cd525fcfd361e1131f0104376d357c8fcb78cf57e12cfdb80598
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code upon opening the workbook. The critical heuristics indicate the presence of dangerous formula APIs within the XLM macro, suggesting it's designed to run commands. No specific family could be identified, but the technique is common for initial execution.

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
1bf088c9291ddff0630f81ace369392abec22db97da4f7836e8bf996fc545a8f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6837 bytes

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