Emotet Office (OOXML) / .XLSM malware analysis — malicious · 6bf15f5975800cb9

MALICIOUS

Office (OOXML) / .XLSM

49.3 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-15

MD5: 7b30a51eeaf1dc531dd36a07e810e9dc SHA-1: 49faed9d01470483ea04e477b77a777127c872ac SHA-256: 6bf15f5975800cb9e28a898724342b9151c1b1a051a7a3ac27d55b4cb4242094

250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The file is an XLSM document containing Excel 4.0 macros, which is a known technique for delivering malware. The macros utilize dangerous functions like FORMULA to download a payload from one of the provided URLs, specifically reconstructing the executable name as 'regsvr32.exe'. The ClamAV detection also identifies it as an Emotet downloader. The embedded URLs are highly suspicious and likely serve as the initial stage for payload delivery.

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.Emotet03221-9941792-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.Emotet03221-9941792-0
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 6 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://alinatourbg.com/mail/TBCGVNzLeENXb/
- http://www.alsancaklimanemlak.com/system/T8nE1jfQ7W/
- http://alsanjari.co.uk/alsanjari.com/CynW/
- http://amasides.my.id/cgi-bin/uFqdwCqAP7mro/
- http://alinac.ca/images/Lp6yKpIpRf6/
- http://amakpost.com/assets/c8AT1uoCVLSxez/
- http://alicehui.com/pics/fETgjDyPfUBQp/
- 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` `561bd2ad03d5ff349d3a0a4fbda71b956dd8d97a0dbce4e25549bf8a7721c5df`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	4049 bytes
`xlm_sheet_01.xml` `4f892349a6f0ce9450df5d764f02eea0a737d43225bc39e0b3e39eaafe266901`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1276 bytes
`xlm_sheet_02.xml` `f8dcec9dac216a8c4fc7140768d73598afe199c381abfb2f58ad13ed8f5733f6`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	1152 bytes

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