Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 fddd055657e1f668…

MALICIOUS

Office (OOXML) / .XLSM

69.8 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-02-26
MD5: 8e7e1158ff64bcba7d6fed28581eebe2 SHA-1: 90e3741f6295b9348cb11fb7629f976e80d8c954 SHA-256: fddd055657e1f668a14fc07f75f773b4678c95ed2ac5cdc0c8f13bbe8d6eab45
270 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 PowerShell T1059.001 PowerShell T1204.002 Malicious File T1059 Command and Scripting Interpreter

This XLSM file contains Excel 4.0 macros, a known technique for delivering Emotet. The macros utilize dangerous functions like FORMULA to call Win32 APIs, enabling the download of a second-stage payload from one of the provided URLs. Specifically, the script attempts to download a file to \Windows\regsvr32.exe and also references an ocx file. The ClamAV detection of 'Xls.Downloader.Emotet03221-9940728-0' further supports this classification.

Heuristics 7

  • Excel 4.0 macro sheet (3 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.Emotet03221-9940728-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03221-9940728-0
  • External relationship medium OOXML_EXTERNAL_REL
    External target in xl/externalLinks/_rels/externalLink1.xml.rels: /Users/Admin/Desktop/File/13j/ZV/ZV.xlsm
  • 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 https://vasilestudio.com/wp-admin/pZ1vbd5Z/
    • https://estesgroup.net/New-site-25062021/UkQPppHG9pLNE/
    • https://robointeligentedecomentarios.com/wp-includes/YBS9a02Y68auiEdP/
    • https://triclicks.net/wp-admin/bv/
    • https://thecanadianarab.com/wp-content/VJ/
    • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
6dd9356952cdd6b95caf156e3e1c1471d7e098b9395e326c2a5a80643c35f018		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3546 bytes
xlm_sheet_01.xml
966e861f35410708893ffb1f97241504111fc93333012aa9c7613d379c3c60bb		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1204 bytes
xlm_sheet_02.xml
67d74ce6825b900ebce4400789acf68e409bb1eeffe279bee966d138d9d814c1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1227 bytes

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