Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7eb49ce58bc55a88…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:25:28 Authoring application: Microsoft Excel First seen: 2021-07-07
MD5: f665cd2ad8fb74320cffc357bd68b85e SHA-1: bf6817df3ce9c88c6be1321775c011651fc68f51 SHA-256: 7eb49ce58bc55a882ffde52b1bd2d7a11660ac43bcf44d419c4525bd187abcb6
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code upon opening the document. The critical heuristic firings indicate the presence of dangerous formula APIs within the XLM macro, suggesting it's designed to run arbitrary commands. The macro sheet itself is named 'PcKUSxhvBX', and the Auto_Open entry is explicitly identified.

Heuristics 3

  • 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.
  • 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 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6632 bytes
SHA-256: 2f8d5e297ef7a2fe23dbfae5e58100bc8cb01bc5055df319d6601391a2d40166
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  PcKUSxhvB
' 0018     20 LABEL : Cell Value, String Constant - AAFmK len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B141 
' 0018     24 LABEL : Cell Value, String Constant - brTAOAbxa len=0 
' 0018     27 LABEL : Cell Value, String Constant - CJDFnMJPGDwr len=0 
' 0018     24 LABEL : Cell Value, String Constant - cLSjlRqoL len=0 
' 0018     20 LABEL : Cell Value, String Constant - dHnPj len=0 
' 0018     24 LABEL : Cell Value, String Constant - eKmoRMPws len=0 
' 0018     26 LABEL : Cell Value, String Constant - fcDJPlrjOkX len=0 
' 0018     22 LABEL : Cell Value, String Constant - FzRkEvx len=0 
' 0018     23 LABEL : Cell Value, String Constant - GaWKnrUz len=0 
' 0018     22 LABEL : Cell Value, String Constant - goWhkvo len=0 
' 0018     24 LABEL : Cell Value, String Constant - KkHxeFIoQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - lfrPI len=0 
' 0018     22 LABEL : Cell Value, String Constant - mMIxzXJ len=0 
' 0018     25 LABEL : Cell Value, String Constant - MqNvbMpHZY len=0 
' 0018     27 LABEL : Cell Value, String Constant - PvMQNhpMaTXn len=0 
' 0018     27 LABEL : Cell Value, String Constant - QSLmwFpwCTsr len=0 
' 0018     27 LABEL : Cell Value, String Constant - SwQwRCXkbsRi len=0 
' 0018     20 LABEL : Cell Value, String Constant - vjfLW len=0 
' 0018     26 LABEL : Cell Value, String Constant - WMllxCfjZfh len=0 
' 0018     26 LABEL : Cell Value, String Constant - xcKxHvPmGZX len=0 
' 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
' 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
'
... (truncated)

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