Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 8983ba37d17ac0b8…

MALICIOUS

Office (OOXML) / .XLSM

50.5 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-14
MD5: 09174499976fb3c50f9624b69ec7aee9 SHA-1: 8d3e079e665a96841d267dd3686e9602078c4084 SHA-256: 8983ba37d17ac0b809f4e6f26e67679f76c9d88587b82ba10f395fab7a0bf85a
290 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1218.010 System Binary Proxy Execution: Regsvr32 T1059.005 Command and Scripting Interpreter: Visual Basic T1105 Ingress Tool Transfer

This XLSM file contains Excel 4.0 macros that leverage dangerous API functions like FORMULA to download payloads from multiple URLs. The macros also construct and execute a command using regsvr32.exe to load a DLL from one of the provided URLs, indicating a downloader functionality. The ClamAV detection as 'Xls.Downloader.Emotet03220-9941298-0' strongly suggests the Emotet family.

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.Emotet03220-9941298-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03220-9941298-0
  • 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 6 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://actividades.laforetlanguages.com/wp-admin/WQNAwrWi77MV8a05fia/
    • http://aopda.org/wp-content/uploads/KXc3Agu18w/
    • http://advogadogoiania.com.br/wp-includes/VTz0V6D/
    • https://www.agenciaigual.com.br/Novo2017/yTZMu9FxcyHYFUkb/
    • http://consejosdeorlando.com/wp-includes/mMaIlj99Y1C1sYN/
    • http://agenciaml.com.br/wp-content/lMGfW5Wk09k/
    • http://101.53.142.76/ApcCache/FiXQvn/
    • 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
b99514d31bf111baca7178f1c3b7e161c3a1df476cfbefb5ab0d85aee00a0f99		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 4031 bytes
xlm_sheet_01.xml
57ec544c624f64a940b22b418ecc97356699a87d8f5405ae8ca128da00e7393a		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1277 bytes
xlm_sheet_02.xml
1a2bbba2a276f955ce94cee47252cbd0a00ecbdfcf526f95f8e33343bc612848		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1152 bytes

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