Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 453f11e9e04ede96…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:42:13 Authoring application: Microsoft Excel
MD5: 695cf42b227bbe04a5571a3a9ecb4c9c SHA-1: 3aeac0db4f86f259db6442db76caf1c993c8a08e SHA-256: 453f11e9e04ede963b19839f84f3beadc42a4ca22fb9f7b2ca545b0f69e18775
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 (XLM) macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics. The presence of an Auto_Open defined name suggests that the macro will execute automatically when the workbook is opened. The dangerous formula APIs used, specifically 'RUN=0', strongly imply that the macro is intended to download and execute a second-stage 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
9e9b5412c6287b6c023c42a74c36cfff0086cc410df61daf620b8501c8621255		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6433 bytes

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