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

Static analysis result for SHA-256 956c30c5d4ba1254…

MALICIOUS

Office (OLE) / .XLSX

31.0 KB Created: 2021-01-25 16:06:26 Authoring application: Microsoft Excel
MD5: 05ffae37d22d1d245dac002d9e868162 SHA-1: b8211f633bdfa03cc27c0b1f03d3eab7baffaf5b SHA-256: 956c30c5d4ba12545014a409777e2f694328489ce9c9907c58d93dcd3ea53985
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.005 Visual Basic T1059.001 PowerShell

The sample is an Excel file containing Excel 4.0 (XLM) macros, specifically an Auto_Open macro. The document body instructs the user to 'enable Editing and Content mode', a common lure to bypass macro security. The XLM macro sheet contains a dangerous formula API call (RUN=0), indicating it's designed to execute commands. No specific URLs or executable payloads were directly extracted, but the presence of the Auto_Open macro and the user-enablement lure strongly suggests a downloader or initial execution stage.

Heuristics 4

  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
75ff87be6d61587b27aed30e745885824d277eb6020de0ea6bebae3b72095296
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3428 bytes