Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 3a4e3f4223ff37eb…

MALICIOUS

Office (OOXML) / .XLSM

33.0 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-16
MD5: 4a24d7f4c7fd5cdaf40488c900984da1 SHA-1: cdb786618da8aece78efef73161094b5c7962db3 SHA-256: 3a4e3f4223ff37eb849d07be929412533699a870e50defa04496a0d342d61e3b
290 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1218.010 System Binary Proxy Execution: Regsvr32 T1059.001 PowerShell

This Excel 4.0 macro-enabled document (XLSM) utilizes dangerous formula APIs to construct and execute commands. Specifically, it leverages regsvr32.exe to download and run a second-stage payload from one of the provided URLs, such as https://www.aulavirtualapecc.com/server/qramDt1UIotz/. The presence of Excel 4.0 macros and the download-and-execute behavior are characteristic of the Emotet family.

Heuristics 7

  • Excel 4.0 macro sheet (1 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.Emotet03222-9941788-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03222-9941788-0
  • 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 https://www.aulavirtualapecc.com/server/qramDt1UIotz/
    • http://calzadoyuyin.com/cgj-bin/uzOOL/
    • http://www.arkidecture.com/vendor/5Ibj6pmUm/
    • https://www.berekethaber.com/dosyalar/2z6RZL/
    • https://ingelse.net/Overview/slWIUhVtK/
    • https://wimmergroup.com/home_tours/Pvnw2/
    • http://bizztream.com/images/NS85wHTdIY9N5Ay/
    • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
db0a59e4a9d5995912532cf04297a579397bf9cc37c53dfcf4ddd0de285133c8		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 4122 bytes

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