Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 8e65f990c1260817…

MALICIOUS

Office (OOXML) / .XLSM

49.4 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-15
MD5: 160771fbacb96ea884b9d6b8490fe9a2 SHA-1: e3de95bc166ddb5beafe04f2f634ac7139764024 SHA-256: 8e65f990c1260817739b4e62d6c9a97a2a1d2a8583ca2383b1e82c62805a9803
250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 PowerShell T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is an XLSM file containing Excel 4.0 macros, identified by critical heuristics for macro sheets, Auto_Open, and dangerous function usage. The macros utilize the FORMULA API to construct and execute commands. Specifically, it appears to download a payload from a list of URLs, including 'https://arealama.com/assets_template/58DBYXQh01ATcsKY/', and save it as 'ujg.dll' in the SysWow64 directory, then execute it via 'regsvr32.exe'. This behavior is consistent with Emotet's known download and execution tactics.

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://arealama.com/assets_template/58DBYXQh01ATcsKY/
    • http://antaoco.com/wp-admin/QpyjXPLrEXf3R9/
    • http://www.automatic-taps.com/Templates/TyJj6dRjzqE/
    • http://arkamani.net/administrator/KIZXGmaRTF6N3qQqH/
    • https://www.artificium.es/blogs/mu8yHJ/
    • https://www.manchesterot.co.uk/about-us/fxVCCMDni/
    • http://www.atara.com.tr/Template/595vJ91nQx/
    • 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.

FilenameKindSourceSize
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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