Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 065881bc75b256fa…

MALICIOUS

Office (OOXML) / .XLSM

20.9 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-18
MD5: 1deb20db3ff4c8a74f81e78d2591ac1c SHA-1: bc1374c09a914a6979fb68a109a87fd9f9c68fb7 SHA-256: 065881bc75b256fac028e2f011b933cbbbef031b5e08fc66301fbeb9ef9851b9
250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The file is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros, which is a strong indicator of malicious intent. The macros utilize dangerous functions like FORMULA to construct URLs and filenames, ultimately downloading and executing a second-stage payload. The ClamAV detection explicitly names this as Emotet, a known downloader family. The reconstructed URL 'http://bramynapilota.com.pl/wp-admin/NHk/' and the execution of 'regsvr32.exe' are key indicators of the payload delivery mechanism.

Heuristics 6

  • 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.Emotet03220-9941789-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03220-9941789-0
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 4 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.manchesterslt.co.uk/a-to-z-of-slt/9wq2ESVcG/
    • http://bramynapilota.com.pl/wp-admin/NHk/
    • http://buildershyper.co.za/s6Oe/
    • https://eephysiotherapy.co.uk/blog/mn1d1JScv1CIg4aTy/
    • http://festival.artdialog.ch/contact/RGhcwH4DRBM/
    • http://brwconsultoria.com.br/img/Vl0i9o/
    • http://business-tailor.nl/ww12/Kz7GjU/
    • 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
bd1141b96e73c592d43d300feb4a2bed92034dffba7d5e49bf95a81f1348fbbc		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 4144 bytes

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