Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 e77671a91cf8bdd6…

MALICIOUS

Office (OOXML) / .XLSM

21.2 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-17
MD5: 951c153a14813bc2d8599526157289fb SHA-1: 49fb4e5e3f60e99a336f3f7f2b46b49bd840df43 SHA-256: e77671a91cf8bdd6ca35d8d93b228add6d7470855b7b2f4b0bc1ff67cac4dbdb
250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1105 Ingress Tool Transfer

This Excel 4.0 macro sheet utilizes dangerous functions like FORMULA to construct and execute commands. The macros are designed to download a second-stage payload from one of the provided URLs, specifically targeting 'http://beetle-j.jp/wp-admin/ErM4mW05tdj/'. The ClamAV detection as 'Xls.Downloader.Emotet03220-9941789-0' strongly suggests an Emotet family infection. The reconstructed string 'regsver32.exe' indicates a potential executable name for the downloaded payload.

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 http://beetle-j.jp/wp-admin/ErM4mW05tdj/
    • http://e3technology.in/2checkout_integration_php/rDcr1Wl90WWA9M/
    • http://bjornbol.dk/wp-includes/ve4cnkjsUMWXC5Cb2bJ/
    • http://bebesel.com.tr/cgi-bin/1wy3oHO/
    • https://brutobrasil.com.br/pdf/toO18cIP3/
    • http://biesenbeek.nl/familie/b6KKlrfH75GD3dHojB/
    • http://bcelectronics.co.za/wp-content/grKnz1V/
    • 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
f9ef0dd03a642623a126a648a3e3b498d8403d13558799b8b55ca81a239f78e5		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3968 bytes

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