Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 17c3ae22fdfe895e…

MALICIOUS

Office (OOXML) / .XLSM

37.4 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-08
MD5: 96894b089f86f09e533792b8753cc984 SHA-1: 4b936fd1501fd43051cfc7238e5344b900efa9d2 SHA-256: 17c3ae22fdfe895e3468e26f55539d4758a93e7564f2588de4fdbe0c5b3a480c
290 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1218.010 System Binary Proxy Execution: Regsvr32

This Excel 4.0 macro-enabled document (XLSM) contains critical heuristics indicating the use of dangerous XLM formula APIs like FORMULA, which are known to be used for downloading and executing payloads. The document body and heuristics explicitly mention `regsvr32.exe` and multiple suspicious URLs, suggesting a pattern of downloading and executing a second-stage payload. The ClamAV detection further supports the identification as Emotet.

Heuristics 7

  • Excel 4.0 macro sheet (3 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.Emotet03220-9940859-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03220-9940859-0
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 5 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://sorathlions.com/tmp/bfJrKD4g0bJL73qw/
    • http://narsanatanaokulu.com/wp-includes/reZNtZ53IH/
    • http://support.techopesolutions.com/gq2z3/yt7TquOtSLXXeade/
    • http://www.invest-moon.com/wp-admin/2PbOcXXyFr4oFoogAA/
    • https://ramijabali.com/licenses/WQu8ZS0qQNGp/
    • http://blog.centerking.top/wp-includes/YvwIBPBq/
    • http://sorathlions.com/t
    • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
f04a70b64ec63683784ca39bae294e6b2c7841eff011398f4b35767fb86e93c1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3899 bytes
xlm_sheet_01.xml
ca7fa26ed4d58d3fd46ef9dc8387e336f3ef9d70dc5dd78639bf3c2c5e458528		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1277 bytes
xlm_sheet_02.xml
0b61b2dde0ca331ea31d988c051388a2c4d7c70e05fe1946e85ab2c205e9d956		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1221 bytes

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