Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d36f8781857b780e…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:44:13 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: 124aa0c9948432e2bbfe5bf90d3ba0ba SHA-1: a324033f94c8c348b5c50802485691ae3fd70e44 SHA-256: d36f8781857b780ea0c8122e6121604bd54d9f3510ea2b1f90b7d1d841aa7830
140 Risk Score

Malware Insights

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

The critical OLE_XLM_AUTOOPEN_DEFINEDNAME and OLE_XLM_DANGEROUS_FN heuristics indicate the presence of an Excel 4.0 macro sheet with an Auto_Open entry. This entry likely executes dangerous formula APIs, enabling arbitrary code execution upon opening the document. No specific family could be identified, and no external IOCs were extracted.

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) 6902 bytes
SHA-256: e66312fbe9e841a4c7ddd7dc524bce692dbbe81903e306ab998bd8495b6fb9c9
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  TdHYPDSLurN
' 0018     24 LABEL : Cell Value, String Constant - AcopZNwpA len=0 
' 0018     27 LABEL : Cell Value, String Constant - AEpMAkbQtqCY len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E171 
' 0018     25 LABEL : Cell Value, String Constant - bHXtirClth len=0 
' 0018     21 LABEL : Cell Value, String Constant - bLApmb len=0 
' 0018     23 LABEL : Cell Value, String Constant - DuFGqOPz len=0 
' 0018     21 LABEL : Cell Value, String Constant - dxaNSW len=0 
' 0018     27 LABEL : Cell Value, String Constant - GcBDxiOQKfUT len=0 
' 0018     24 LABEL : Cell Value, String Constant - iNZFnsIdg len=0 
' 0018     20 LABEL : Cell Value, String Constant - jiymA len=0 
' 0018     26 LABEL : Cell Value, String Constant - MzRGXaGPhdR len=0 
' 0018     25 LABEL : Cell Value, String Constant - nkEWnmDqSK len=0 
' 0018     27 LABEL : Cell Value, String Constant - OBWuKkpDoUnC len=0 
' 0018     27 LABEL : Cell Value, String Constant - PbqJzcPnHoBZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - PkvbJlbWpI len=0 
' 0018     24 LABEL : Cell Value, String Constant - pZVsNUqUS len=0 
' 0018     22 LABEL : Cell Value, String Constant - qNyiWts len=0 
' 0018     24 LABEL : Cell Value, String Constant - RxYQTshbY len=0 
' 0018     25 LABEL : Cell Value, String Constant - UcGOaGKdmr len=0 
' 0018     21 LABEL : Cell Value, String Constant - VWJRhW len=0 
' 0018     23 LABEL : Cell Value, String Constant - zYIVTyrP 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
... (truncated)

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