Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 306aa9d554ff4ef6…

MALICIOUS

Office (OOXML) / .XLSM

43.3 KB Authoring application: 14.0300 First seen: 2022-03-06
MD5: 06c691ddc2b4b9d1f609dc080d38e71f SHA-1: 9d651fcba1c4decaf226f7256c51068e398a7910 SHA-256: 306aa9d554ff4ef6789cd52d8455d15e2456166939d17b64b238cbea00f62fff
230 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1218.010 System Binary Proxy Execution: Regsvr32 T1059.005 Command and Scripting Interpreter: Visual Basic

This XLSM file contains Excel 4.0 macros that leverage dangerous formula APIs to construct and execute a command. The macro attempts to download a payload from several URLs using regsvr32.exe, as indicated by the 'SE_LOLBIN_RUN_COMMAND' heuristic and the reconstructed command line in the DOC BODY. The ClamAV detection and the nature of the execution point towards the Emotet family, which commonly uses this delivery method.

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.
  • 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.Emotet03220-9940726-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03220-9940726-0
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 3 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://nataliapereira.com/wp-admin/pE8xYY3x6p/
    • http://annewelshsalon.com/wp-admin/2c9l2o1/cWWAzTVQ/
    • http://hellocloudgurusgerald.com/wp-content/iXYx/
    • https://ramijabali.com/licenses/0/
    • https://africa-roadworks.com/lilo-bard/vk3GSY7/
    • http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/main
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac
    • http://schemas.microsoft.com/office/excel/2006/main
    • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
55706ee9a0b2ebe16e2ab6bed347353c00948b27eb98bd0ab3fdb5e70b19242c		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 3782 bytes

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