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

Static analysis result for SHA-256 710865356a14f4c2…

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-27 11:38:08 Authoring application: Microsoft Excel
MD5: e9e773a89ac799db3c031f70c81b221a SHA-1: 1ffef90d2f4bd76c5854b4ccaa5701ffb6be415b SHA-256: 710865356a14f4c209b0bf79e534990823c01bbda274c97424f033f43aadf8ca
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel spreadsheet containing Excel 4.0 macros, indicated by the presence of an 'Auto_Open' defined name and the use of dangerous formula APIs. This suggests the macro is designed to execute automatically upon opening the file, likely to download and execute a secondary payload. No specific family could be identified.

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
02ddb626792a2e238505c317715742945fa6492f61d6f0f5442a010691ae845e		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6705 bytes

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