Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 48f3ef54ff2ed0b4…

MALICIOUS

Office (OOXML) / .XLSM

46.6 KB Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-31
MD5: 07f30f1fa5420f050ea5929af0f95265 SHA-1: 6310b51fca4003fb36252367f058c2e990ba5734 SHA-256: 48f3ef54ff2ed0b44d5e4836c56a3a8f3214d7214278172ef84166f6d42cc067
250 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample is an XLSM file containing Excel 4.0 macros, specifically utilizing the dangerous FORMULA API. This API is used to construct and execute commands that download payloads from multiple URLs, including 'http://eles-tech.com/css/KzMysMqFMs/'. The ClamAV detection as 'Xls.Downloader.Emotet-b600c9ff3ec1c136-9950239-0' strongly suggests the Emotet family. The macros appear to be designed to download and execute a second-stage payload, likely a DLL or EXE, from the provided URLs.

Heuristics 6

  • 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.Emotet-b600c9ff3ec1c136-9950239-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-b600c9ff3ec1c136-9950239-0
  • 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 http://eles-tech.com/css/KzMysMqFMs/
    • https://txpcrescue.com/cgi-bin/5tSO8/
    • http://haribuilders.com/zoombox-master/4HYGX/
    • http://gonorthhalifax.com/wp-content/yTmYyLbTKZV2czsUO/
    • http://hadramout21.com/jetpack-temp/Py/
    • http://hansen-arnal.com/cp/iiTrAeEtvOwmjjekWgI/
    • 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.

FilenameKindSourceSize
xlm_sheet_00.xml
4153191ccbeaead436d640cd9bad7b4c39fa54474c8ec9a17be8e3e4600146ed		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3602 bytes

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