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

Static analysis result for SHA-256 54b25a2685a879f1…

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-25 10:38:58 Authoring application: Microsoft Excel
MD5: 7880f75ded523eff41ea5a1983c7e064 SHA-1: 1312726022371fb0204b6d3d703d651dce68dec0 SHA-256: 54b25a2685a879f13e9ff6a7e8317fbf37d797658e37a0e602995ec0e72cfe5f
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 the RUN function within the Auto_Open macro indicates an attempt to execute arbitrary commands upon opening the document. This is a common technique for initial execution of malicious payloads.

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
894abf4c21a12c52d3a9af6697acd82804ca1ba5db1b7f0ef43bf0c120f9f3ad		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6698 bytes

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