Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ef39ad640943ff72…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:40:34 Authoring application: Microsoft Excel First seen: 2021-10-14
MD5: 007c20517afab72e5c9ed96b468288d0 SHA-1: 11dbcb86b6739805dc9203564ea0e293fa0a7223 SHA-256: ef39ad640943ff72b43a7e342d6759346a8b448f59b0099b54a5a9bcad837fd0
140 Risk Score

Malware Insights

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

The file contains critical heuristic firings indicating the presence of Excel 4.0 macros with an Auto_Open function. This function is designed to automatically execute when the workbook is opened, serving as a mechanism for initial execution of malicious code. The specific dangerous formula API 'RUN' was identified, suggesting the macro attempts to run an external process or command.

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) 6536 bytes
SHA-256: 64b4e486b9410e584524b7882787cde575e04e77bba27a4a9b783c3ea48b42ed
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  KYM
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F184 
' 0018     25 LABEL : Cell Value, String Constant - BUMacCoXya len=0 
' 0018     22 LABEL : Cell Value, String Constant - BXBAUjw len=0 
' 0018     24 LABEL : Cell Value, String Constant - dLUSQBwyr len=0 
' 0018     27 LABEL : Cell Value, String Constant - dutSVRMOZLCE len=0 
' 0018     20 LABEL : Cell Value, String Constant - FEcro len=0 
' 0018     21 LABEL : Cell Value, String Constant - GnYBmM len=0 
' 0018     27 LABEL : Cell Value, String Constant - HorncBefkMfi len=0 
' 0018     25 LABEL : Cell Value, String Constant - jzKpPjpdiN len=0 
' 0018     20 LABEL : Cell Value, String Constant - kaxTd len=0 
' 0018     20 LABEL : Cell Value, String Constant - MGBfG len=0 
' 0018     26 LABEL : Cell Value, String Constant - oALVKnqgWfu len=0 
' 0018     22 LABEL : Cell Value, String Constant - OHEGziD len=0 
' 0018     25 LABEL : Cell Value, String Constant - qXbMSywRLz len=0 
' 0018     22 LABEL : Cell Value, String Constant - rDvhQNU len=0 
' 0018     21 LABEL : Cell Value, String Constant - rnWyuK len=0 
' 0018     25 LABEL : Cell Value, String Constant - SANesAJmxL len=0 
' 0018     26 LABEL : Cell Value, String Constant - sdfpJnMSiBh len=0 
' 0018     21 LABEL : Cell Value, String Constant - ugVSRL len=0 
' 0018     24 LABEL : Cell Value, String Constant - xOngAGjmF len=0 
' 0018     25 LABEL : Cell Value, String Constant - XowtwNtLBl 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     10 L
... (truncated)

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