Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 9573f30a3736e5a5…

MALICIOUS

Office (OOXML) / .XLSM

75.1 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-14
MD5: 0527190e179a3edc760cc2283a2fcec3 SHA-1: e321d1e2f896b5bc60d07531777667b58142d33c SHA-256: 9573f30a3736e5a5faa293b35204a571a3729d05854e2526bb321b32946f4651
250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1071.001 Web Protocols

This XLSM file contains Excel 4.0 macros, including an Auto_Open macro, which is a critical indicator of malicious intent. The macros utilize dangerous API calls like FORMULA to download and execute payloads. The reconstructed URLs indicate the file attempts to download a second-stage payload, likely a component of the Emotet banking trojan, from multiple remote servers. The presence of 'regsvr32.exe' and '.ocx' file paths suggests an attempt to register a malicious component.

Heuristics 6

  • 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.Emotet03220-9941786-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03220-9941786-0
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
26edf9bacfee50b5986426c79eb3159c595a38f59b61b257c6666d6dbea79cdc		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3854 bytes
xlm_sheet_01.xml
16728df0c83af9edbca13e7bf934528980971291f8afa9e213237ad5e9c550aa		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1275 bytes
xlm_sheet_02.xml
eb62ea8fd79da591769622356698b97ab3294ef8032cb3ffcd8f29cb5968841e		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1213 bytes

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