Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 f8df82e32c99d37c…

MALICIOUS

Office (OOXML) / .XLSM

48.4 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-07
MD5: 8d0e5d035fa64088ac69eee48546ed30 SHA-1: 1eed467413274c7d54b5da87063aeb9206a41b40 SHA-256: f8df82e32c99d37c96565ef09644c78575b7408b6c4dae2c3fde26877090d388
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, identified by the OOXML_XLM_MACROSHEET and OOXML_XLM_AUTOOPEN_DEFINEDNAME heuristics. The macros utilize dangerous XLM formula APIs like FORMULA to download payloads from multiple URLs, including http://henrysfreshroast.com/OevI7Yy0i6YShxFl/. The extracted DOC BODY content explicitly shows the use of regsvr32.exe with the downloaded payload '..\si.ocx' to execute the second-stage malware. This behavior is consistent with Emotet's known delivery methods.

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.Emotet03221-9940858-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03221-9940858-0
  • 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://henrysfreshroast.com/OevI7Yy0i6YShxFl/
    • http://aopda.org/wp-content/uploads/5oTAVJyjDFOllX2uE/
    • http://1000paginas.com/tienda/vWtT/
    • http://www.ajaxmatters.com/c7g8t/nnzJJ1rKFD2P/
    • https://winnieswondersaviary.com/wp-content/mxPfty43IionmElgK3h/
    • http://crm.techopesolutions.com/b48om9p6/vquxKuTvTj/
    • http://henrysfreshroast
    • 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
f04a70b64ec63683784ca39bae294e6b2c7841eff011398f4b35767fb86e93c1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3899 bytes
xlm_sheet_01.xml
ca7fa26ed4d58d3fd46ef9dc8387e336f3ef9d70dc5dd78639bf3c2c5e458528		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1277 bytes
xlm_sheet_02.xml
0b61b2dde0ca331ea31d988c051388a2c4d7c70e05fe1946e85ab2c205e9d956		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1221 bytes

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