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

Static analysis result for SHA-256 a65f412405a8bee4…

MALICIOUS

Office (OLE) / .XLSX

138.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2022-07-13
MD5: e0ca79a2b92ca860fd56a9138457dabc SHA-1: 6815f744bbbd164f4305425541db7dcada236711 SHA-256: a65f412405a8bee47bcb66feeef5052016f8452567df3faef58b834dd1a387f8
160 Risk Score

Malware Insights

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

The critical OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics indicate the presence of an Excel 4.0 macro sheet with an Auto_Open function that calls dangerous APIs like RUN. The SE_ENABLE_LURE heuristic confirms the document attempts to trick the user into enabling macros. The embedded URL and filename suggest a downloader payload is being fetched and executed.

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
3a08691eed72e5ed205a0b2d682f61d57bf1de10bae67e5c55da30ecdcba1b08		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 4335 bytes

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