Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c8f6a071b5c57b99…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:40:27 Authoring application: Microsoft Excel First seen: 2021-10-14
MD5: 71a4b26d05c9077d3b6c37232f5e9586 SHA-1: 179f2fcc0a4af600089c689b9cdb0ff3451bd2c6 SHA-256: c8f6a071b5c57b998c5bac1e885ef1bf04d6415c88556a5f5b5281aba122bbbf
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 macros, specifically an Auto_Open function. This function is designed to execute automatically when the workbook is opened, indicating an attempt to run arbitrary code. The presence of dangerous formula APIs within the macro sheet further supports its malicious intent.

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) 6601 bytes
SHA-256: 479fae2991286e4bd60a39476bd9d8fbb95c43b7e5acf6fda7efc57d423a2201
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  MDpc
' 0018     26 LABEL : Cell Value, String Constant - AAryZeEVVmP len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I171 
' 0018     25 LABEL : Cell Value, String Constant - bVdvZIfsgs len=0 
' 0018     23 LABEL : Cell Value, String Constant - dsQjajxW len=0 
' 0018     22 LABEL : Cell Value, String Constant - Dyrfhct len=0 
' 0018     23 LABEL : Cell Value, String Constant - gMRpsmZP len=0 
' 0018     20 LABEL : Cell Value, String Constant - HdVan len=0 
' 0018     25 LABEL : Cell Value, String Constant - kBmfrXOYmG len=0 
' 0018     21 LABEL : Cell Value, String Constant - msWFCx len=0 
' 0018     23 LABEL : Cell Value, String Constant - oQLEuKZO len=0 
' 0018     24 LABEL : Cell Value, String Constant - PApjjJPDI len=0 
' 0018     23 LABEL : Cell Value, String Constant - PwkzuZYf len=0 
' 0018     20 LABEL : Cell Value, String Constant - rFXxn len=0 
' 0018     26 LABEL : Cell Value, String Constant - RMzRAcHYOjD len=0 
' 0018     20 LABEL : Cell Value, String Constant - TliEp len=0 
' 0018     20 LABEL : Cell Value, String Constant - VtFFt len=0 
' 0018     23 LABEL : Cell Value, String Constant - wcILNczY len=0 
' 0018     23 LABEL : Cell Value, String Constant - yAyitxLQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - yGyFbPv len=0 
' 0018     20 LABEL : Cell Value, String Constant - zcCHb len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZPTPpoK 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 LABELSST : Cell V
... (truncated)

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