Emotet Office (OOXML) / .XLSM malware analysis — malicious · f04a78d47b71d96d

MALICIOUS

Office (OOXML) / .XLSM

37.3 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300

MD5: 0f7f66ad3960134dffb484bef5354967 SHA-1: efd30cd6d179019949a9a4344fb61781d82335f7 SHA-256: f04a78d47b71d96d886fb1ee98718c003645a8f1e921ac0e0a6458ac3e814c3e

250 Risk Score

Malware Insights

Emotet · confidence 90%

MITRE ATT&CK

T1204.002 User Execution: Malicious File T1059.005 Command and Scripting Interpreter: Visual Basic for Applications T1105 Ingress Tool Transfer T1140 // a bit of too much, but maybe a {

The sample is an XLSM file containing multiple Excel 4.0 macro sheets (XLM) using the FORMULA() API to execute system commands. The document body contains obfuscated strings that, when reconstructed, reveal the use of 'url download to file' via rundll32.exe to download a payload named 'besta.ocx' from three distinct URLs: 'http://crackedshop.org/9/q080U0ARYYL/', 'https://ascarya.digital/wp-content/ZH4rirU/', and 'http://thesesenscollection.com/wp-admin/5jtAxMp1TTZ7Y/'. ClamAV specifically identifies this as Emotet.

Heuristics 6

Excel 4.0 macro sheet (8 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.EmotetExcel122100-9913103-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.EmotetExcel122100-9913103-0
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 11 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 8

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `7e43fd3a34b9a01e861dfe456c68f67abfb2b8f42dd37b661b6a0dfb8c8fb495`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	3257 bytes
`xlm_sheet_01.xml` `ceb5adcada0214181e536a8a058cb456fbcfe4a486d29cd185c8117200520be1`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1365 bytes
`xlm_sheet_02.xml` `8a64aa30d99902ea7a99a9b90b1ee1238a58df11dd8419d899ea7dd6d334096d`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	1366 bytes
`xlm_sheet_03.xml` `eb9bfe9bdebda540c828894dc4e9149e1ba7a2691d1ed56b3b04fb6d9a36191e`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet3.xml	1363 bytes
`xlm_sheet_04.xml` `2758b4ba64fea766c088d247a1498ea08c026fe41c5c21d48ad4f0f8b7be5e57`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet4.xml	1363 bytes
`xlm_sheet_05.xml` `6451df65cc10e1503db4d453a64f73a9026417657722c57f6ed147c8ec6708ac`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet5.xml	1366 bytes
`xlm_sheet_06.xml` `baa175c596711727ab65048b590e8e52a70cdec06148a9d046c2a6286ecdf57f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet6.xml	1365 bytes
`xlm_sheet_07.xml` `e72f152fc995eb1f1ad88257e6ba1c18f0602a7fbede21eb23a670a9c64dfe55`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet7.xml	1365 bytes

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