Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b376187b735d05b9…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:47:09 Authoring application: Microsoft Excel First seen: 2021-07-13
MD5: 91fb305cde2f7c7bb62fdace36ea6ad5 SHA-1: 143d62b1f9edc6b1e5fa65dcc53900ca7a2bf6c6 SHA-256: b376187b735d05b97f395602e8d7947c413c936f6148a7386f624e336a213f1c
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook. Static analysis detected an Auto_Open defined name, indicating that a macro will execute automatically when the workbook is opened. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary commands, likely to download and run a second-stage payload.

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) 6652 bytes
SHA-256: e896ba6a9a2f0bf7fd59bb40b4a25339ab274424956ed0844aa0252b652a597e
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 -  CpBv
' 0018     22 LABEL : Cell Value, String Constant - AdfdNfh len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F190 
' 0018     27 LABEL : Cell Value, String Constant - bljyVlyhEYmM len=0 
' 0018     22 LABEL : Cell Value, String Constant - DabIIeT len=0 
' 0018     24 LABEL : Cell Value, String Constant - eLQpssBVs len=0 
' 0018     23 LABEL : Cell Value, String Constant - ExSOTVUG len=0 
' 0018     20 LABEL : Cell Value, String Constant - fFyHk len=0 
' 0018     21 LABEL : Cell Value, String Constant - FHbedA len=0 
' 0018     21 LABEL : Cell Value, String Constant - KYVjyZ len=0 
' 0018     26 LABEL : Cell Value, String Constant - LzqUYRkFVsg len=0 
' 0018     20 LABEL : Cell Value, String Constant - mUPhx len=0 
' 0018     26 LABEL : Cell Value, String Constant - NnwRfsQMNOn len=0 
' 0018     20 LABEL : Cell Value, String Constant - PKoYZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - QQTtosHAiD len=0 
' 0018     27 LABEL : Cell Value, String Constant - RFHQGqTaldKy len=0 
' 0018     27 LABEL : Cell Value, String Constant - smzLLdhBoawZ len=0 
' 0018     26 LABEL : Cell Value, String Constant - STcVmUplwBL len=0 
' 0018     26 LABEL : Cell Value, String Constant - ttjZHEUYjUO len=0 
' 0018     21 LABEL : Cell Value, String Constant - uOGqkn len=0 
' 0018     20 LABEL : Cell Value, String Constant - YmIqE len=0 
' 0018     25 LABEL : Cell Value, String Constant - YrTbkxWALb 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
... (truncated)

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