Emotet Office (OOXML) / .XLSM malware analysis — malicious · 5b04d034241d6000

MALICIOUS

Office (OOXML) / .XLSM

33.6 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-16

MD5: 812290d5d6a1aacc3b4dae3b2c946165 SHA-1: 37642ce807a560a7a19bc75c14a26faa947cbc68 SHA-256: 5b04d034241d60008ca8009126817a2d4bf30537906863565f988e6e4e9e70ff

290 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK

T1059.005 Visual Basic T1218.010 System Binary Proxy Execution: Regsvr32

The sample is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros, which is a known technique for delivering Emotet. The macros utilize dangerous XLM formula APIs to download a payload from one of the embedded URLs and execute it using regsvr32.exe. The ClamAV detection also confirms the Emotet family.

Heuristics 7

Excel 4.0 macro sheet (1 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.Emotet03222-9941788-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.Emotet03222-9941788-0
LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND

Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
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://www.alejandrovillar.com/MSL/eKDWjpa4OHRxpysOTFe/
- https://alexetaurore.com/wanted/pfFtzaJovICU81kfuUp/
- http://balibuli.hu/cgi-bin/WDDM0VHSK4VcOFmU/
- https://al-brik.com/vb-w/U/
- https://alejandrastamateas.com/web/ZxA3zHwsH3r/
- http://ayursoukhya.org/wp-includes/XI35qPGHvszZ1u/
- https://aldibiki.com/prettyPhoto/gLFRzQV0VunO/
- 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 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `db0a59e4a9d5995912532cf04297a579397bf9cc37c53dfcf4ddd0de285133c8`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	4122 bytes

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