Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f0bf4da547b3e77f…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:41:36 Authoring application: Microsoft Excel
MD5: 232f3a3d783f12c2e2ffc440ca971eb9 SHA-1: 1f1a2ddcfc83fce32758f723fa30ed280476b804 SHA-256: f0bf4da547b3e77f7648cce83a819bcf461d8b1122e3f955310ba2dbaa2e07f8
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook. Static analysis detected an Auto_Open defined name and the use of dangerous formula APIs within the XLM macro sheet, indicating an attempt to automatically execute code upon opening. The macro sheet contains obfuscated data and references to potentially dangerous functions, strongly suggesting it's designed to download and execute a secondary 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
c927d28e6f29c8a1608e3cfaeb53d044132862a9bc37454a2812062b84f1f573		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6578 bytes

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