Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 19b08163e2ecb955…

MALICIOUS

Office (OOXML) / .XLSM

37.2 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 706b703865f4cfebbe895aabc0e174c6 SHA-1: 993933066d665f12e6067baf6dc785f97401e195 SHA-256: 19b08163e2ecb9559eeefced25a9164b45e3718b1707d8a624533da66f1bff14
250 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file is an XLSM document containing Excel 4.0 macros, which is a known distribution method for Emotet. The macros utilize dangerous formula APIs like FORMULA to call Win32 functions, specifically 'URLDownloadToFileW'. This function is used to download a second-stage payload from one of the three provided URLs, such as 'http://www.promocionderecho1983unmsm.com/licenses/YqHdHi4JP6IR/', saving it as 'besta.ocx'. The presence of hidden sheets and the ClamAV signature further support the Emotet family attribution.

Heuristics 6

  • Excel 4.0 macro sheet (8 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: 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.
  • ClamAV: Xls.Downloader.EmotetExcel122100-9913104-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.EmotetExcel122100-9913104-0
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 11 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • 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 http://www.promocionderecho1983unmsm.com/licenses/YqHdHi4JP6IR/
    • http://alittlebrave.com/wp-content/ZelFnTyMYZZFFnBS36fPSl/
    • https://www.cursossemana.com/wp-content/qjIChEom3Dr4I7BJ4Ol/
    • 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
    • http://schemas.microsoft.com/office/spreadsheetml/2014/revision
    • http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision3
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 8

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
2080d6210c68e38acccfb5be0db73a68ff4253f34b9fa123f5684b1445c0d1fc		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3220 bytes
xlm_sheet_01.xml
ceb5adcada0214181e536a8a058cb456fbcfe4a486d29cd185c8117200520be1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1365 bytes
xlm_sheet_02.xml
8a64aa30d99902ea7a99a9b90b1ee1238a58df11dd8419d899ea7dd6d334096d		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1366 bytes
xlm_sheet_03.xml
eb9bfe9bdebda540c828894dc4e9149e1ba7a2691d1ed56b3b04fb6d9a36191e		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1363 bytes
xlm_sheet_04.xml
2758b4ba64fea766c088d247a1498ea08c026fe41c5c21d48ad4f0f8b7be5e57		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet4.xml 1363 bytes
xlm_sheet_05.xml
6451df65cc10e1503db4d453a64f73a9026417657722c57f6ed147c8ec6708ac		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet5.xml 1366 bytes
xlm_sheet_06.xml
baa175c596711727ab65048b590e8e52a70cdec06148a9d046c2a6286ecdf57f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet6.xml 1365 bytes
xlm_sheet_07.xml
e72f152fc995eb1f1ad88257e6ba1c18f0602a7fbede21eb23a670a9c64dfe55		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet7.xml 1365 bytes

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