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

Static analysis result for SHA-256 73ff7586ca15d6c1…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:30:25 Authoring application: Microsoft Excel
MD5: c0f84359099732345b95f16675de71a2 SHA-1: 219cab942cbe13a72f49581aab449c2afd72adf7 SHA-256: 73ff7586ca15d6c132f90ed3de1bb16a99997c6f7cf5404e2703dd080d71c6f3
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file is an Excel spreadsheet containing Excel 4.0 macros, indicated by the presence of an Auto_Open defined name. This macro sheet is configured to automatically execute upon opening, which is a common technique for launching malicious payloads. The specific dangerous functions used, such as RUN, suggest an intent to execute arbitrary code or download additional malware.

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
57fb962245dad9f892c20371aa64261f891f0891ee70b906895cb0c26a274a5d		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6609 bytes

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