Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 f82b408b7fc3dd60…

MALICIOUS

Office (OOXML) / .XLSM

40.0 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-04
MD5: d83ce3f9355a6bcc2b5a7cf51b585252 SHA-1: 7fa6ffe971818656ee761ed3d0cf1e16fff2fa53 SHA-256: f82b408b7fc3dd60a8b396a22f9dd5d33932280d0ca7801f6f41f1985a725018
290 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 T1105 Ingress Tool Transfer

This XLSM file contains Excel 4.0 macros, which are known to be used for malicious purposes. The macros utilize dangerous functions like FORMULA to construct and execute commands. Specifically, it constructs a command to download and execute a payload using regsvr32.exe from a list of embedded URLs. The ClamAV detection as 'Xls.Downloader.Emotet03220-9940731-0' strongly suggests an Emotet family infection.

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.Emotet03220-9940731-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03220-9940731-0
  • 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 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://foroviviendaparaguay.com/wp-admin/hx8U6XMffnkv8HI2Oig/
    • http://ghsjalkherabsr.com/oz03n/6XeYLjFXcFE/
    • http://www.aacitygroup.com/wp-content/EkY9/
    • http://en.pachammer.com/wp-content/vIG/
    • http://ghsmadonabsr.com/wp-includes/Of4kQNCp2WLy0F4B/
    • https://theoutsourcedaccountant.com/images/nFikTQmP/
    • http://foroviviend
    • 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
94965f752a1e7be43d1bf315273deead3f139a3387887345fe87c8486a290891		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3704 bytes
xlm_sheet_01.xml
351feaae7418c65a74e6a0ba66009b604df9b81504ed5e5dbe43c90a37e65a77		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1278 bytes
xlm_sheet_02.xml
e7d03b45d335889b8dde35df06f3ab1a1e873e88cc653bc40b000e1458d4c807		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1152 bytes

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