Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 3abf08d0ab7e261e…

MALICIOUS

Office (OOXML) / .XLSM

37.1 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: d7a6cf7b59e3e57e2d67efec413b7841 SHA-1: 088a2e1c986933f87698d154c5aa691512e83f96 SHA-256: 3abf08d0ab7e261ef78e74827d43424fce41bbf98ffef48994c6d17c86f172cc
250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer

The file is an XLSM document containing Excel 4.0 macros, as indicated by multiple critical heuristic firings including OOXML_XLM_MACROSHEET and OOXML_XLM_DANGEROUS_FN. The macros utilize dangerous XLM formula APIs like FORMULA to download and execute payloads from the reconstructed URLs: "https://duocphamct.com/wp-content/JYT0KrYcoJrAj/", "https://ordereasy.hk/error/8BZswf/", and "https://test.ohmyhome.com/licenses/W/". The macros also attempt to save a file named "..\bestb.ocx" and execute it using rundll32.exe or regsvr32.exe. This behavior is consistent with Emotet's known delivery methods.

Heuristics 6

  • Excel 4.0 macro sheet (7 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.EmotetExcel122100-9913103-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.EmotetExcel122100-9913103-0
  • 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://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 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
bb44205236f15184b0ac9b4a66871ce7b09cc6f06bfbce8f204e360695863e43		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3052 bytes
xlm_sheet_01.xml
1d840e58b613d5aaf0c1584ddad983c459013d0020172bf8c42753a3ca5c10ce		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1367 bytes
xlm_sheet_02.xml
9530473eeb7ce4531ba6f2fb74f3f8b15d5970a3f986b2de8204ee4e69d17bcb		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1367 bytes
xlm_sheet_03.xml
5298b05c0f3d1a953d0ede7427cc089251a7652227e518fae265a133c04b11f5		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1364 bytes
xlm_sheet_04.xml
5f53215a8438bb7fe5a809106144bae36a7af9a316481ee676680c60ac4893c6		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet4.xml 1364 bytes
xlm_sheet_05.xml
466ccb4b7c309940a771659ee00d4db755bdde38abf836c5ee99a946f296d356		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet5.xml 1367 bytes
xlm_sheet_06.xml
85d88333fb0430df1cb4b286e0f1d952b0e36ae77f3e113b23aadd6e029134fc		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet6.xml 1366 bytes

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