Emotet Office (OOXML) / .XLSM malware analysis — malicious · a34269b9a7885bca

MALICIOUS

Office (OOXML) / .XLSM

45.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-02

MD5: d83d1e345ccad9ff0cef3c0c185c5d4d SHA-1: 1fe1d391951668086c76300ba2079c337a7f7d7a SHA-256: a34269b9a7885bcacdb034c6dd0550dd1a7dc52a65982b6cc64a5d43bdaf0319

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

This XLSM file contains Excel 4.0 macros, specifically utilizing the FORMULA API to download and execute a payload. The macros construct URLs from concatenated strings, pointing to several suspicious domains. The ClamAV detection as 'Xls.Downloader.Emotet03220-9940726-0' strongly suggests an Emotet family infection. The primary intent is to download and execute a second-stage payload from the identified URLs.

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.Emotet03220-9940726-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.Emotet03220-9940726-0
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 http://api.zmotpro.com/totalenvironment/logs/8wdgNaq0x/
- https://mustknew.com/lovecalculator/osDBhPqx0tB1Vtp/
- http://aetoaluminium.com/wp-admin/gkqyKlzXoc/
- http://kiski023.com/wp-includes/Requests/Cookie/C/
- http://24studypoint.com/wp-admin/3uEUtb/
- https://baicc-ct.org/wp-admin/IwhcfC2sdxoToa/
- 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` `c2beed76b90707ab99d3556b095847fbe67565665bab2978d4d40d1b769c68e7`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	4017 bytes
`xlm_sheet_01.xml` `3f1e04bcb932a0d7a0ca09ad6e05d398d7a144c4cda86314010c0ec3e9f94573`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1278 bytes
`xlm_sheet_02.xml` `3877aa64e871d2d6fcc766f5b3af64ba0d301f656023d2e6e43652b8210d827c`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	1152 bytes

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