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

Static analysis result for SHA-256 242b4194830be626…

MALICIOUS

Office (OLE) / .XLSX

42.0 KB Created: 2020-09-28 00:53:43 Authoring application: Microsoft Excel
MD5: 5d170bb3659d3a93037271432411c3f1 SHA-1: 752824fb0ac8ce6ebca7ea03843b259813e9364c SHA-256: 242b4194830be62620b2460afd024d0fba2333c14c9b43573a5ceb7468f93aef
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell T1204.002 Malicious File

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. The macros utilize dangerous formula APIs, including the RUN function, indicating an attempt to execute arbitrary code. This is a common technique for delivering secondary payloads.

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
a6a5cc93c57cd0031140d8318dd377471b5c5415af73c7221775a8196a1b6e2a		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7936 bytes

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