Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 1550569adcf8cd47…

MALICIOUS

Office (OOXML) / .XLSM

37.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-18
MD5: 07c55c4400e092f87deb62a1c68b17e3 SHA-1: 1afb6c783da7e2f253fd125d71a06ffc4485cc56 SHA-256: 1550569adcf8cd47ec90663741e39f1ea86291c97f06773e6e7fd5feb0ef0012
250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an XLSM document containing Excel 4.0 macros, identified by ClamAV as Emotet. The macros utilize dangerous formula APIs like FORMULA to download and execute payloads from multiple URLs. Specifically, the script attempts to download from 'webstream.jp/died-wing/oOzfVc/' and save it as 'dfeb.ses' in the Windows directory, likely using 'regsvr32.exe' for execution.

Heuristics 6

  • Excel 4.0 macro sheet (2 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.Emotet03221-9941790-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03221-9941790-0
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 5 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
193a597cf9347ebbb9d332eb02b3e4aa560f5f6938f1d13ef5649cb957b20db4		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1507 bytes
xlm_sheet_01.xml
8cf9d5b82b850f313d6893a5c0508b35482ae584949aaa5244e60fb5b25b6ef4		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 4239 bytes

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