Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 30aec2c78e4ad36a…

MALICIOUS

Office (OOXML) / .XLSM

48.4 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-08
MD5: 0fd3a2e547acbbf48c780ca105b457fc SHA-1: fb0447a8b7fbfaf2f98f69c0781b5e1bb0acdb02 SHA-256: 30aec2c78e4ad36aec44c6f3be6c1971753d02e9215a78dba33ff8179d7f34f6
290 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1218.010 System Binary Proxy Execution: Regsvr32 T1059.001 Command and Scripting Interpreter: PowerShell T1105 Ingress Tool Transfer

This XLSM file contains Excel 4.0 macros, specifically utilizing the dangerous FORMULA API to call external Win32 functions. The macros are designed to download and execute a payload using regsvr32.exe with the argument "..\ax.ocx" and a URL. The ClamAV detection as 'Xls.Downloader.Emotet' strongly suggests the Emotet family. The embedded URLs are indicative of a downloader mechanism.

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.Emotet03221-9940858-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03221-9940858-0
  • 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://suleyera.com/components/CNGhltc5v2K6/
    • http://moveit.savvyint.com/config/DsfssbO7BYG/
    • http://sociallysavvyseo.com/PinnacleDynamicServices/pRlYMzvfuu5B/
    • https://schwizer.net/styled/D0MG/
    • http://suleyera.com/comp
    • http://shabeerpv.atwebpages.com/css/ww6if1YAsMpjpuGz/
    • http://shimal.atwebpages.com/wp-content/xkaRkHr/
    • 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
f04a70b64ec63683784ca39bae294e6b2c7841eff011398f4b35767fb86e93c1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3899 bytes
xlm_sheet_01.xml
ca7fa26ed4d58d3fd46ef9dc8387e336f3ef9d70dc5dd78639bf3c2c5e458528		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1277 bytes
xlm_sheet_02.xml
0b61b2dde0ca331ea31d988c051388a2c4d7c70e05fe1946e85ab2c205e9d956		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1221 bytes

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