Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 6b8bec7a27e7d6c2…

MALICIOUS

Office (OOXML) / .XLSM

86.8 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 14.0300
MD5: 5dbab77f96e877a66e6deb3809e967c1 SHA-1: f930cb4b9a6d9e4b8086c8647b5e1aba620afc44 SHA-256: 6b8bec7a27e7d6c2a302cc0b379ef24902fd47e68772d54890abad406c414bfe
182 Risk Score

Malware Insights

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

The sample is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. Heuristics indicate the use of dangerous XLM functions like EXEC and CALL, which are used to download and execute payloads. The macros construct a URL from concatenated strings and attempt to execute it, indicating a downloader functionality. The presence of the Auto_Open defined name further suggests automatic execution upon opening.

Heuristics 4

  • Excel 4.0 macro sheet (2 sheet(s)) critical OOXML_XLM_MACROSHEET
    Spreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks.
  • Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAME
    Workbook defines _xlnm.Auto_Open or _xlnm.Auto_Close while containing an XLM macro sheet. This is the OOXML/XLSB auto-execution shape for Excel 4.0 macros.
  • Dangerous XLM formula APIs: WORKBOOK.HIDE, EXEC, CALL, HALT, FORMULA critical OOXML_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA). These are the primitives used to download payloads, write files, and start processes from an XLM macro without invoking VBA.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://hannahchinedu.com/dQSUQzeUwN/04.html
    • https://abpnco.com/nayWPlQM/04.html
    • http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.microsoft.com/office/excel/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
emf_00.emf
442eb38c1c88060cf62c1fd88f48f9b8961edd687fe9250cf42ff79baf20ccae
ooxml-emf OOXML EMF part: xl/media/image1.emf 296536 bytes
xlm_sheet_00.xml
e2d0c69c580969a640d565ee7f4c9f99c84cac5b5d64c997ece3e584778305c8
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1638 bytes
xlm_sheet_01.xml
bc0107a78ea6ba702702ddf8b745f24672051acbfa84cd527ab65f9785d5a729
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 3777 bytes