Trickbot — Office (OOXML) malware analysis

Static analysis result for SHA-256 df135ad578e0dc73…

MALICIOUS

Office (OOXML)

118.9 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 16.0300
MD5: 1b53a6b7a34f1147239394dbe8e32dd0 SHA-1: 653b5169d95699f1faf9e01f173d74908abf5480 SHA-256: df135ad578e0dc731e04f791fe645159cce61670bedc2cc0775aa83f68833cb7
250 Risk Score

Malware Insights

Trickbot · confidence 95%

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

This Excel file contains Excel 4.0 macros, identified by multiple critical heuristics. The macros utilize dangerous functions like FORMULA and EXEC to download a DLL payload from the URL http://162.248.225.95/d.php and execute it using regsvr32. The ClamAV detection further confirms its malicious nature, specifically identifying it 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

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