Emotet Office (OOXML) / .XLSM malware analysis — malicious · 599f6f21b36e1114

MALICIOUS

Office (OOXML) / .XLSM

173.5 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-02-28

MD5: 16b0a46874078ef5b0e0b17518011c5c SHA-1: 2bf4dcc341aeb083bd595e08ba082d4e127f4b61 SHA-256: 599f6f21b36e111424dc10abf458d7fe769d06fe6e71d5b6c81c2c7d269ffae1

250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK

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

The sample is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. Critical heuristics indicate the use of dangerous XLM formula APIs like FORMULA, which are used to download and execute payloads. The DOC BODY and SCRIPTS sections reveal reconstructed URLs and commands that indicate the macro attempts to download a second-stage payload from one of the listed URLs and execute it using 'regsvr32.exe'. The ClamAV detection name 'Xls.Downloader.Emotet' strongly suggests the Emotet family.

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.Emotet-a5251d3d2d6d3722-9951020-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.Emotet-a5251d3d2d6d3722-9951020-0
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://carretilha.net/whats/RSL50BlRP0a6hj/
- https://shrinandrajoverseas.com/old/wQXty0wnVDY/
- https://zionimoveis.com.br/wp-content/Bn00gaw/
- https://kontacsgo.pl/m/uwZYNUjGeWW/
- http://vps36153.publiccloud.com.br/wp-admin/RfAZZ776uMNhSpOT/
- 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` `90e37e1ee0ab1fa1161bc9308b04f0f335c97d1feb756097ceb983695c1599e5`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	3554 bytes
`xlm_sheet_01.xml` `966e861f35410708893ffb1f97241504111fc93333012aa9c7613d379c3c60bb`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1204 bytes
`xlm_sheet_02.xml` `60579741b1b65a4181fd818a651bece32da461189f50a30098e233a7c5fed525`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	1227 bytes

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