Emotet Office (OOXML) / .XLSM malware analysis — malicious · b893e475fee41eb3

MALICIOUS

Office (OOXML) / .XLSM

95.3 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-02-26

MD5: 6b0bd115c2c4c054616ec596dd62b384 SHA-1: 1125e2d626ba533e2e86fda5831fec1071dbe7f4 SHA-256: b893e475fee41eb39579f5b96037aa692359843e50a3e046bf498d13ecdd40ec

250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK

T1059.005 Service Execution: Visual Basic T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 Malicious Link: Malicious File T1105 Ingress Tool Transfer

The file is an XLSM document containing Excel 4.0 macros, as indicated by multiple critical heuristic firings including OOXML_XLM_MACROSHEET and OOXML_XLM_DANGEROUS_FN. The macros utilize the FORMULA API to construct and execute commands. Specifically, the macros appear to download a payload from one of the provided URLs, such as 'https://distribucionespariente.com/wp-includes/YHQ1W1R2iSznft2vO/', and execute it using 'regsvr32.exe'. This behavior is consistent with Emotet's known delivery methods.

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.Emotet02220-9940466-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.Emotet02220-9940466-0
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 https://distribucionespariente.com/wp-includes/YHQ1W1R2iSznft2vO/
- https://makspeedtech.com/cgi-bin/6BuOTbA/
- https://newmainghantabazar.com/wp-includes/tyiPqbUMvMq79yMyM8E/
- https://mbahauddin.com/v/2horjuyP/
- https://cafedeltren.t1.curious.tech/v/oa9AwvFnbCZ59xoyBB/
- 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.

Filename	Kind	Source	Size
`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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