Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 090c4d74eeec5818…

MALICIOUS

Office (OLE) / .XLS

269.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-19
MD5: b9df0979054234d185de7d78370c67a5 SHA-1: ce0236deb133f295ba4c8ea08e652c2b069c8825 SHA-256: 090c4d74eeec5818496f0ee02a51ccb1d523dc036bc486a55f1aeae3b4a344e3
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro that uses dangerous functions like RUN. This indicates the file is designed to execute arbitrary code upon opening. The ClamAV detection and the presence of URLs suggest it functions as a downloader for a second-stage payload, consistent with Emotet's typical behavior.

Heuristics 4

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • ClamAV: Xls.Downloader.Emotet-MSOLE2-af43432fbcb8603c-9980047-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-MSOLE2-af43432fbcb8603c-9980047-0
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
4ce2eca84e77657cf47cd88188d1109ed7a2a5940734c07a9d94627fa54370cf		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7149 bytes

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