Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 649d4346cd9ce734…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:43:36 Authoring application: Microsoft Excel First seen: 2021-06-04
MD5: 7972622e7516c23303d81e96f777f01e SHA-1: e3701d73ee351e58ed2e75f20889c1c84827cf09 SHA-256: 649d4346cd9ce73403d789a5b0b01baeb5f6477575c9f9739179a747afe7a270
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 method for executing malicious code upon opening the workbook. The critical heuristics indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it is designed to run arbitrary commands. No specific family could be identified, but the technique is common for initial execution.

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) 6453 bytes
SHA-256: dbf1300972864509868bc543ac01e0fbe81af9fa8d96e2f8c9ea309958afc1b9
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  QHSdZ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D166 
' 0018     25 LABEL : Cell Value, String Constant - BALCqJimOC len=0 
' 0018     26 LABEL : Cell Value, String Constant - BMLcfDSWQuL len=0 
' 0018     21 LABEL : Cell Value, String Constant - cWbZEV len=0 
' 0018     24 LABEL : Cell Value, String Constant - CzRQucMMj len=0 
' 0018     25 LABEL : Cell Value, String Constant - dplLzYaPue len=0 
' 0018     25 LABEL : Cell Value, String Constant - dwqgnUGeYV len=0 
' 0018     22 LABEL : Cell Value, String Constant - DXAGMrD len=0 
' 0018     25 LABEL : Cell Value, String Constant - EthUYIEuYQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - FlIYz len=0 
' 0018     20 LABEL : Cell Value, String Constant - gBJfy len=0 
' 0018     24 LABEL : Cell Value, String Constant - hFuDaDDrB len=0 
' 0018     26 LABEL : Cell Value, String Constant - KTWvarLcvfd len=0 
' 0018     23 LABEL : Cell Value, String Constant - MyCYOdNF len=0 
' 0018     23 LABEL : Cell Value, String Constant - opveDGTZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - OwcZjBXdZY len=0 
' 0018     25 LABEL : Cell Value, String Constant - swXaWYENam len=0 
' 0018     25 LABEL : Cell Value, String Constant - UAyxUiafnE len=0 
' 0018     25 LABEL : Cell Value, String Constant - uygNrUJwcA len=0 
' 0018     20 LABEL : Cell Value, String Constant - vyxcV len=0 
' 0018     24 LABEL : Cell Value, String Constant - zNrmkzAjk 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
' 00fd  
... (truncated)

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