Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4539ded5f34784c1…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:41:42 Authoring application: Microsoft Excel
MD5: bf1e5583f1ee029a914e0f79a85ad806 SHA-1: f454911f4a2765f047eb7ea0a1ff4160bcb4e422 SHA-256: 4539ded5f34784c1200339a14d049f255154721fe6766317d1962a34fb27d52e
140 Risk Score

Malware Insights

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

The file is an Excel workbook containing Excel 4.0 macros, specifically an Auto_Open defined name. Heuristics indicate the use of dangerous formula APIs within the Auto_Open macro, suggesting an intent to execute arbitrary code. The presence of an Auto_Open macro is a common technique for initial execution of malicious payloads in older Excel versions.

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
0bcdf78d56534d0ea356ccd916be33596aa370d83391c50e093cace9796347c1		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6394 bytes

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