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

Static analysis result for SHA-256 8a49debc4cc8008a…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:46:12 Authoring application: Microsoft Excel
MD5: 7dfb9db57b875bb1758f846c2aac2fde SHA-1: b6c4462df5b4b6ce7d8c483c635a04685e1b8c3b SHA-256: 8a49debc4cc8008a169c10c3c7f18b7e6021a5fceb6247fb8455c0e67d9384e8
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample contains Excel 4.0 macro sheets with an Auto_Open defined name, indicating it's designed to execute code automatically upon opening. The critical heuristic firings confirm the presence of dangerous formula APIs like RUN, suggesting the macro is intended to download and execute a second-stage payload. No specific family could be identified from the available evidence.

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
2a64cdaaaa9ebb06b9d77940ff7ad5aae7a01e4db5242dfcf5c055af2a268595		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6879 bytes

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