Emotet — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 0fbb989a9655d26a…

MALICIOUS

Office (OOXML) / .XLSX

102.8 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 33198743d7766396ecfed94ea73c96fc SHA-1: 3dad6f8a5e20f9d5070e0105c315a58a4d3d0274 SHA-256: 0fbb989a9655d26a65e7ba0d0365ec737dbd5a2321402d16f6f96fcabe1e856f
250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The file contains Excel 4.0 macros, indicated by multiple critical heuristic firings including 'OOXML_XLM_MACROSHEET' and 'OOXML_XLM_DANGEROUS_FN'. These macros are designed to download and execute a second-stage payload. Specifically, the macros construct URLs such as 'http://deckoface.in/_errorpages/2l/', 'http://luoicauthang.com/css/m6RaglUnYVXJ7mw2W/', and 'http://www.nouvelleesthetique.it/wp-includes/lM1Gp51/', and use functions like 'URLDownloadToFileA' and 'rundll32.exe' to download and run a file named 'bestb.ocx'. The ClamAV detection also explicitly names this as an Emotet variant.

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.