Trickbot — Office (OOXML) malware analysis

Static analysis result for SHA-256 b5f97ae3a3a1e8b6…

MALICIOUS

Office (OOXML)

118.3 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 16.0300
MD5: c18060b8641d70ef7464d8f01238871e SHA-1: 7eb8ba75037dab3e606e7abcfd0b63d25381479a SHA-256: b5f97ae3a3a1e8b67463ff509f91167ee7a624e616664901c32d9aef3cd4c051
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 Excel 4.0 macro sheets with Auto_Open defined names and dangerous API calls like FORMULA and CALL. These macros are designed to execute commands, specifically to download a DLL payload from the URL http://162.248.225.95/d.php and save it as ..\fsdfjhghkj.dll. The ClamAV detection also identifies 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
0663285629b46f633ca14b7eacfe84f9a5c571dbf830207c837e8153c4d1eeae		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 1559 bytes
xlm_sheet_02.xml
febb675c687f398915561000cb0ce5d88a8b1757db7b14528ba7e9d85e8a088d		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml 1841 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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