Dridex — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 c190db17fb46c7a8…

MALICIOUS

Office (OOXML) / .XLSM

210.2 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000
MD5: f1ed106609467e1a52d1ce49382cce4a SHA-1: fad596e0a7f25e024b6f6e63c8f6b6baff667ce5 SHA-256: c190db17fb46c7a896f008e0afdeecf1e214fcd16d66a3a35d5a3566dd68e34c
250 Risk Score

Malware Insights

Dridex · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1059.003 Windows Command Shell

The file is an XLSM document containing Excel 4.0 macros. The macros utilize dangerous functions like EXEC, FOPEN, and HALT. Specifically, the EXEC function is used to execute a script located at 'C:\ProgramData\RQYHFjEuPR.sct'. This indicates a downloader pattern, consistent with the Dridex family. The use of Excel 4.0 macros to directly call Win32 APIs for execution is a critical indicator.

Heuristics 6

  • Excel 4.0 macro sheet (1 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: EXEC, HALT, FOPEN, FWRITE, FCLOSE 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.DridexCyan08210-9887648-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.DridexCyan08210-9887648-0
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
0f923ffd34ae7cd27d0b0c0206221bea13b5ae71122150c868d25a2294ab51cc		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 120901 bytes

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