Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 59742a2cc223b820…

MALICIOUS

Office (OOXML) / .XLSM

35.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-23
MD5: 3790bb21970c6b34281684ed4006e5ac SHA-1: 767771c133dfb4e0620b075ae22988b88fcc8edf SHA-256: 59742a2cc223b8202786dbe8769dd89a4c87e0e0d1a4f6f69eae0658b6f57515
250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1105 Ingress Tool Transfer

The file is an Excel 4.0 macro sheet (XLSM) containing dangerous functions like FORMULA, which are used to download and execute payloads. The ClamAV signature 'Xls.Downloader.Emotet03221-9941790-0' strongly suggests the Emotet family. The macros construct URLs and commands, including 'regsvr32.exe' and paths like 'SysWow64\Windows\', indicating a downloader function that fetches and executes a second-stage payload, likely an OCX file, from the listed URLs.

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
56299d8024c4f1ac82a7522c7ead08f39677c0bae82297826862fce76df69744		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1495 bytes
xlm_sheet_01.xml
8e2616826469cdb87cf1c4eb49e8c201b264eceb93468f26315db51abb9ca50d		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 4178 bytes

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