Trickbot — Office (OOXML) malware analysis

Static analysis result for SHA-256 82305c5f4ea27c78…

MALICIOUS

Office (OOXML)

118.9 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 16.0300
MD5: 553366c55b08c5d02d779b693dcb45ce SHA-1: 291cc5cc3957df3dcfbddb77ddd1e16208580705 SHA-256: 82305c5f4ea27c78f7c0459f0a3d9dd8a83333e0d6c75d31e16ba22a6f4e7555
250 Risk Score

Malware Insights

Trickbot · confidence 95%

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

The file contains critical Excel 4.0 macro sheet heuristics, including the use of dangerous functions like FORMULA and HALT, and an Auto_Open defined name. The extracted DOC BODY reveals the macro's intent to download a DLL named 'totpre.dll' from the URL 'http://162.248.225.95/d.php' using 'regsvr32' for execution. ClamAV also identified the file as a Trickbot downloader.

Heuristics 6

  • Excel 4.0 macro sheet (5 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, HALT 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.Trickbot07210-9880007-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Trickbot07210-9880007-0
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 1 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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
ead8cdcc18ca09a9f1328ae9399750e4baa9e7c6fb8ca17b0bd770971aea3f01		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 229062 bytes
xlm_sheet_01.xml
2d3c928d0d7ee7e605de7622c7daeaaddc10bb6a90253ac3d4dc0d493ae1f3ff		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 1688 bytes
xlm_sheet_02.xml
613b2b73b0caaed4a0b1cadca1ad142425adc75b20c60ac08ab3fa4bc1a3dbd9		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml 1773 bytes
xlm_sheet_03.xml
57537cc8466ada117081e749fe7167446f3f5d029fd4fb1612ea0261027bc6c1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml 1778 bytes
xlm_sheet_04.xml
9cf98f4732ae983fd46d8cf179488facaeec3ec6d78e683880682236b3dbdb0e		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml 1879 bytes

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