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

Static analysis result for SHA-256 c704efd5f63bdfde…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:44:20 Authoring application: Microsoft Excel
MD5: 48a05693a7a96c86a7fdd270747f6deb SHA-1: d96f59017a9d31c8f77714102bc56f3e604f840b SHA-256: c704efd5f63bdfde0af5bf3a216c1fcc3cf1b7e542b209878354de724ae712dd
140 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macro sheets with an Auto_Open defined name, indicating automatic execution upon opening. The critical heuristic 'OLE_XLM_DANGEROUS_FN' specifically flags the use of dangerous formula APIs like RUN within the Auto_Open macro. This suggests the macro is designed to execute arbitrary commands, likely to download and run a second-stage payload.

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
9e41bf492ad5ba8998ac4d120adc66e2f59adecfcd058bdca48f3da6abfa639d		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6524 bytes

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