Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 6b4caa5c5cdb7822…

MALICIOUS

Office (OOXML) / .XLSM

46.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-01
MD5: eccb73a9e13b3f8385fa1291d52025fc SHA-1: 022c1a5b7dbc0bbaeae396c00a48ee2f24a3dbd3 SHA-256: 6b4caa5c5cdb78222bf223e7d71f6191531643cb6adcd4e067bdfded14169fc4
290 Risk Score

Malware Insights

Emotet · confidence 95%

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

This Excel document contains Excel 4.0 macros that utilize dangerous formula APIs to download and execute payloads. The macros construct URLs and command lines to fetch and run a second-stage payload, likely using regsvr32.exe. The ClamAV detection and embedded URLs strongly suggest Emotet family activity.

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.Emotet03220-9940726-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03220-9940726-0
  • 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://aquapark.hotelrestoranaqua.com/wp-includes/a1eCjuFRWXku/
    • http://kopkomerc.rs/wp-includes/css/ErPamucLecQSqd/
    • https://baksen.org/chat/8wYoYwWXH4eidiUOAs/
    • http://restoran.hotelrestoranaqua.com/wp-includes/67I/
    • https://truetvkerala.com/wp-admin/iocOOm7I/
    • https://lavanya-aesthetic.com/cgi-bin/PjtfI2BlnvUtlMV2vTR/
    • http://aquapark.hotelrestoranaqu
    • 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
c2beed76b90707ab99d3556b095847fbe67565665bab2978d4d40d1b769c68e7		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 4017 bytes
xlm_sheet_01.xml
3f1e04bcb932a0d7a0ca09ad6e05d398d7a144c4cda86314010c0ec3e9f94573		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1278 bytes
xlm_sheet_02.xml
3877aa64e871d2d6fcc766f5b3af64ba0d301f656023d2e6e43652b8210d827c		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1152 bytes

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