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

Static analysis result for SHA-256 9d929c67a113b593…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:25:35 Authoring application: Microsoft Excel
MD5: b20124561a77ba73f3d53f334df55b5d SHA-1: 337627d84ed65398301d100d9c1f1fc9b8e276ad SHA-256: 9d929c67a113b59340cf2c92bb734e5a90b90dbdd7e197504f853041ce9a233a
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates the workbook is designed to automatically execute macro code upon opening. The presence of dangerous formula APIs like RUN further confirms the intent to execute arbitrary commands. No specific malware 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
a673bad74ecb739e9931cf028afebb2c38346922f2b548538b4c05d961ee7499		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6593 bytes

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