Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 75de78f56cf15f63…

MALICIOUS

Office (OOXML) / .XLSM

45.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-02
MD5: 0684e0f1848b9344dadb8921186ef872 SHA-1: 9217672bcf6824f450c029badb0d7a8bd5c78ae3 SHA-256: 75de78f56cf15f63276eed7bd3b02402fddf8bfc385e246c9255ea4d30140bc4
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 sample is an XLSM file containing Excel 4.0 macros, as indicated by multiple critical heuristic firings including the use of dangerous formula APIs like FORMULA. These macros are designed to download and execute a second-stage payload from one of the embedded URLs. The ClamAV detection name 'Xls.Downloader.Emotet03220-9940726-0' strongly suggests the Emotet family. The script attempts to download a file using regsvr32.exe.

Heuristics 6

  • 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
  • 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://api.zmotpro.com/totalenvironment/logs/8wdgNaq0x/
    • https://mustknew.com/lovecalculator/osDBhPqx0tB1Vtp/
    • http://aetoaluminium.com/wp-admin/gkqyKlzXoc/
    • http://kiski023.com/wp-includes/Requests/Cookie/C/
    • http://24studypoint.com/wp-admin/3uEUtb/
    • https://baicc-ct.org/wp-admin/IwhcfC2sdxoToa/
    • 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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