Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 37167ec92c621ae4…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:38:56 Authoring application: Microsoft Excel First seen: 2021-10-07
MD5: 86134bee4dbb4a80a7efa88fbc4088bc SHA-1: 77cce6677a6280e3cd329e3cacdf52ef8912af19 SHA-256: 37167ec92c621ae4fffd1d4b557291e06affb7f3e24e166d445e0f050153ab09
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open function, which is a common technique for executing malicious code upon opening the document. The `RUN` function was identified as a dangerous API call within the macro, suggesting it attempts to execute arbitrary commands or load external content. No specific family could be identified, but the technique strongly suggests a downloader or initial execution stage.

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) 6471 bytes
SHA-256: 1e38681c11f0f877fd1806e03fe22ab1d2037b03fcf4732a45a5bd86ab39282d
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 -  WvlGQ
' 0018     27 LABEL : Cell Value, String Constant - AdNGjTJaWOfU len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I165 
' 0018     24 LABEL : Cell Value, String Constant - dtsZIGckJ len=0 
' 0018     20 LABEL : Cell Value, String Constant - eFtGX len=0 
' 0018     27 LABEL : Cell Value, String Constant - euymOSnENUQw len=0 
' 0018     24 LABEL : Cell Value, String Constant - FGRRWfhek len=0 
' 0018     24 LABEL : Cell Value, String Constant - FzUwzybjV len=0 
' 0018     27 LABEL : Cell Value, String Constant - IFnuWVAuuqUE len=0 
' 0018     21 LABEL : Cell Value, String Constant - JwdqzF len=0 
' 0018     21 LABEL : Cell Value, String Constant - KHHLEG len=0 
' 0018     27 LABEL : Cell Value, String Constant - rPatEopNdZpe len=0 
' 0018     25 LABEL : Cell Value, String Constant - tYLgCGwVok len=0 
' 0018     20 LABEL : Cell Value, String Constant - UheNo len=0 
' 0018     26 LABEL : Cell Value, String Constant - vCRmzStyukM len=0 
' 0018     25 LABEL : Cell Value, String Constant - WDNKIfbiMy len=0 
' 0018     24 LABEL : Cell Value, String Constant - WwWrljsWX len=0 
' 0018     22 LABEL : Cell Value, String Constant - WYzDKLr len=0 
' 0018     26 LABEL : Cell Value, String Constant - xOUbcAxArke len=0 
' 0018     26 LABEL : Cell Value, String Constant - XTIyWfBMAgJ len=0 
' 0018     24 LABEL : Cell Value, String Constant - YcgGrvKqE len=0 
' 0018     21 LABEL : Cell Value, String Constant - YwTeDj 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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