Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 6c9fd3fc054d8dad…

MALICIOUS

Office (OOXML) / .XLSM

38.8 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-18
MD5: 76b9b0fcbadf74328f94ce2eb012a340 SHA-1: 1fe1de0d964f195e07e953aac93ec4da6aba407c SHA-256: 6c9fd3fc054d8dad8a7523003c24766aa5f7769b41ab68607e589b8aefd48c9e
250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an XLSM file containing Excel 4.0 macros, which are known to be used by Emotet for downloading malicious payloads. The macros utilize dangerous functions like FORMULA to construct URLs and execute commands. Specifically, the macros appear to construct the URL "http://pianistprodigy.com/demolms/Ax6ZgvEJJ8HEKfXrp/" and then execute "regsvr32.exe" from the SysWow64 directory, indicating a clear intent to download and run a second-stage payload.

Heuristics 6

  • Excel 4.0 macro sheet (2 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.Emotet03221-9941790-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03221-9941790-0
  • 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://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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
a0c0f3e40bb0bcb71f69feab4a546d6971a6ad22d842de019237e043f0081a43		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1772 bytes
xlm_sheet_01.xml
2f8447d752b9aa82298eff83e8f17bd62a63f1ba62e6405681193f1dc7729f67		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 4474 bytes

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