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

Static analysis result for SHA-256 5116a11899832178…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:43:00 Authoring application: Microsoft Excel
MD5: 5f91c9f214d169024ae39da1ee546520 SHA-1: 5483ad5cce083474379c0bcdfb86055f55bda687 SHA-256: 5116a1189983217881d1d34ba415c0fd47862926e07be9bdae00065fad1571e0
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell

The sample contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. The presence of the 'RUN' function within these macros indicates an attempt to execute arbitrary code. This is a common technique for initial execution of malicious 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
3b7969c6ccaae52906767310049692e788fd0d5f87311950e4911d376e9bc0a1		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6403 bytes

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