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

Static analysis result for SHA-256 149cca92ffc565e4…

MALICIOUS

Office (OLE) / .XLSX

132.0 KB Created: 2020-11-20 17:59:00 Authoring application: Microsoft Excel
MD5: 7feae78f818876db3f23147e18ede3bf SHA-1: efb689ce29193aa45daffd1f83ab26206b8c94ca SHA-256: 149cca92ffc565e46abbc10fd652af3ecf811d92486a3341836bd792f4f34842
148 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample contains Excel 4.0 macros, specifically an Auto_Open macro that executes a PowerShell command. This command constructs a URL to download a file named 'gy.exe' and then executes it. The VBA project itself contains no executable statements, indicating the primary malicious functionality resides within the XLM macros.

Heuristics 4

  • 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.
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
f97452a2a8f934575f044798b4f1b5e0f6e694779389797df8c7fea3bfe995fe		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1889 bytes
macros.bas
fed365d3401536fb63e11d0a36cc7c35338c0a8c74a96fb254c46366ad6287cd		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 642 bytes

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