Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 809a8c36346ee4ec…

MALICIOUS

Office (OOXML) / .XLSM

90.2 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-02-23
MD5: 942216790fff84e9ac548ee182710bba SHA-1: e5d0b9d37f797bf63ff8aaf4f89d245f0f777a0d SHA-256: 809a8c36346ee4ec52676f3a82c4e540366165169da7546f55721907a338afa6
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 functions like FORMULA to download and execute payloads. The macros construct URLs and then use regsvr32.exe to fetch and run a second-stage component from these URLs. The ClamAV detection and the use of regsvr32.exe for remote code execution strongly indicate 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.EmotetExcel02220-9940032-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.EmotetExcel02220-9940032-0
  • 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://www.ajaxmatters.com/c7g8t/zbBYgukXYxzAF2hZc/
    • http://www.beholdpublications.com/home/BABxyyWZx8Vu/
    • http://explorationit.com/screwing/AxLm/
    • http://donboscoschoolputhuppally.org/wp-content/UuQ7LBsPoGu9Q/
    • http://myclassroomtime.com/mongery/ZlPsROtQiXIujmJmAA/
    • http://www.ajaxmatters.com/c7g8t/zbBYgukXYxzAF
    • 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
fc9253ffcb683b17b2963a329e0d1078315a68ecc8af492238ff27be69741b1f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3613 bytes
xlm_sheet_01.xml
6922c877af9b5ffe857609a5d410eac153e8905bd35dfd19cf6ef8e3fb0636e6		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1204 bytes
xlm_sheet_02.xml
60579741b1b65a4181fd818a651bece32da461189f50a30098e233a7c5fed525		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1227 bytes

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