Emotet — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 8d98679c7e482ac9…

MALICIOUS

Office (OOXML) / .XLSX

102.8 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 54911e2ba91792e2d1d265ebe52d3ec0 SHA-1: bbf2a09c231eabed85da4e7a1b474f36ff462a30 SHA-256: 8d98679c7e482ac92e8bfa579781caac2be2740868a2e9d9cefa3e95d9a07a23
250 Risk Score

Malware Insights

Emotet · confidence 95%

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

This malicious Excel file utilizes Excel 4.0 macros, specifically leveraging dangerous functions like FORMULA, CALL, and EXEC to download and execute a second-stage payload. The macros construct URLs by concatenating strings, such as 'http://deckoface.in/_errorpages/2l/', 'http://luoicauthang.com/css/m6RaglUnYVXJ7mw2W/', and 'http://www.nouvelleesthetique.it/wp-includes/lM1Gp51/', which are then used to fetch and run additional malware. The ClamAV detection name 'Xls.Downloader.EmotetExcel01222-9935624-0' strongly suggests an Emotet family infection.

Heuristics 6

  • Excel 4.0 macro sheet (7 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.EmotetExcel01222-9935624-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.EmotetExcel01222-9935624-0
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 9 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 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
cc3c760d021dc0f92f6b8a31258dbda1f4fe62686d9454e8aea5f91fd5d5a51e		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3001 bytes
xlm_sheet_01.xml
59fb56fc58fd232563a22867c20a884d6289f09f0c79869664f200eb18083ed9		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1276 bytes
xlm_sheet_02.xml
936d303af08b53433e824bd515ff133310f5cff0167aacad4837d6a70e0485aa		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1276 bytes
xlm_sheet_03.xml
17855edc6796afbb0c6baab513b4cd688cd5290a5cd33c6df6d22bfd7956a7ee		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1276 bytes
xlm_sheet_04.xml
e435c23f0c54e9a8e2c3c73f8190fa8ab2441a219c1eae2b9a9623cb899f7772		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet4.xml 1273 bytes
xlm_sheet_05.xml
01e0b2a256cecd08e1d22b47d62d2bccf9e83a4249289bf05aa95a32228e2547		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet5.xml 1275 bytes
xlm_sheet_06.xml
17e78319db707e4ee9281b0a633a93c66fe9a2780a5c2e1cecea51dd0c1a692e		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet6.xml 1276 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.