Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 d15f48ae6c04d596…

MALICIOUS

Office (OOXML) / .XLSM

36.1 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 4d13de5eb5930accd727d69d64a3fe7f SHA-1: 57041661114527ed2a16f6b30bc42add61722966 SHA-256: d15f48ae6c04d596a056f35837f3ea63b4ad948f87b7a8ef301b8ca2fef8dcb8
250 Risk Score

Malware Insights

Emotet · confidence 90%

MITRE ATT&CK
T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 User Execution: Malicious File T1105 Ingress Tool Transfer T1547.001 Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder T1218.011 System Binary Proxy Execution: Rundll32 T1129 나s a single JSON object only. No prose, no markdown, no code fences. The object must have exactly these keys: { "attack_ T1027 Obfuscation

The sample uses Excel 4.0 macros (XLM) to download a payload from one of several hardcoded URLs, including 'http://new.amazonbroker.com/MsQseVusvE9YRl/DpLceIxuG3t0ALQ/', 'http://new.hsnbroker.com/7/Pggi69PuxiPPLgVd/', and 'http://new.qvcbroker.com/3/OW5E1T2x/'. The script then saves the payload as 'C:\Windows\bestb.ocx' and executes it using 'rundll32.exe' via the 'DllRegisterServer' export. This pattern is highly characteristic of Emotet, which is further supported by a ClamAV detection for Xls.Downloader.Emotet.

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
f51df967c9a79675ef430ab610a20d6a4c94bb90710f2dafb84224b8e8da9eac		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3032 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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