Emotet Office (OOXML) / .XLSM malware analysis — malicious · 2556a5f5964e1806

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: 03bfd0b270ff280659ae60155bac73f6 SHA-1: 5d4ab882ba83a769ff61da4fd44cb04e8cffa884 SHA-256: 2556a5f5964e1806bbaf9337378a53fdbc20363cffca2da8e78889464b37bca4

250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is an XLSM file containing Excel 4.0 macros, 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://realitevirtuelleguadeloupe.com/warp-visa/xogkV/', and save it as '\Windows\SysWow64\regsvr32.exe' for execution. This behavior is consistent with Emotet's typical download and execution chain.

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://realitevirtuelleguadeloupe.com/warp-visa/xogkV/
- https://nuugebeya.com/wp-content/LqCYYSBQ/
- https://larassatistore.com/mail.tie-collection.my.id/SZZ0/
- https://bimbeladzkia.com/1600-arrow/njvK9lEVwMfxQyw/
- https://vendedoramigo.com.br/wp-admin/tfQwLyk4/
- 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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