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

Static analysis result for SHA-256 01bd7813317bd291…

MALICIOUS

Office (OLE) / .XLS

2.02 MB Created: 2008-04-16 07:00:56 Authoring application: Microsoft Excel
MD5: 4913113e67a1d229eb7a3e3bfc73cc06 SHA-1: c8afe87699199240cf608b5825e90e54784686f1 SHA-256: 01bd7813317bd291a4602facb5f2a2d006e13e55fd5e55ed1763cdea1614466d
200 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 (XLM) macros, indicated by multiple critical heuristic firings including OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN. The presence of the 'RUN' function within these macros strongly suggests the execution of arbitrary commands, likely to download and execute a second-stage payload. The document body contains what appears to be a list of names and dates, possibly a lure, but the primary malicious functionality stems from 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.
  • Legacy Excel formula macro virus marker critical OLE_XLS_FORMULA_MACRO_VIRUS
    Workbook stream contains self-identifying legacy Excel formula macro virus markers. This indicates the document carries formula macro virus content even when no VBA project or modern XLM macro-sheet structure is present.
  • 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
3387c8734b066328373b186c7cdde272733dab226418d1fa9dcba9213676be6c		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1566874 bytes

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