Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ff2b3b70778185f5…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:43:56 Authoring application: Microsoft Excel First seen: 2021-06-04
MD5: a6d96c26bc2cc7e88659002959930364 SHA-1: b03e5d4c5399abdad7b35cbbb54a1c2660ddc0e8 SHA-256: ff2b3b70778185f5b227c768f55f3b7be379465cd816859f67eab9dfda449fbd
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 sheet containing an Auto_Open function, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_AUTOOPEN_DEFINEDNAME heuristics. The OLE_XLM_DANGEROUS_FN heuristic specifically flags the use of dangerous formula APIs like RUN, suggesting the macro is designed to execute arbitrary code. The exact nature of the payload is not discernible from the provided evidence, but the presence of an Auto_Open macro with dangerous functions strongly implies 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) 6520 bytes
SHA-256: 12d561ef99fd7fb65847c25a18e971cfb742989c4441507f907b367e51e5ad7c
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 -  xqrrK
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G201 
' 0018     27 LABEL : Cell Value, String Constant - bvtxopdHTcrk len=0 
' 0018     21 LABEL : Cell Value, String Constant - DFXuXL len=0 
' 0018     25 LABEL : Cell Value, String Constant - EORAurcAyO len=0 
' 0018     25 LABEL : Cell Value, String Constant - exhcYMSvuM len=0 
' 0018     22 LABEL : Cell Value, String Constant - fRdhFQd len=0 
' 0018     22 LABEL : Cell Value, String Constant - gitdwhu len=0 
' 0018     26 LABEL : Cell Value, String Constant - JziSQZLShZn len=0 
' 0018     27 LABEL : Cell Value, String Constant - LAVUFSlzLIHH len=0 
' 0018     22 LABEL : Cell Value, String Constant - Nzqbbef len=0 
' 0018     26 LABEL : Cell Value, String Constant - PuTPyijlUoW len=0 
' 0018     24 LABEL : Cell Value, String Constant - QFmzMWiZs len=0 
' 0018     21 LABEL : Cell Value, String Constant - rbWKGx len=0 
' 0018     21 LABEL : Cell Value, String Constant - sQyCrc len=0 
' 0018     23 LABEL : Cell Value, String Constant - upyRCWcv len=0 
' 0018     22 LABEL : Cell Value, String Constant - VHFinFx len=0 
' 0018     27 LABEL : Cell Value, String Constant - VwaRGRkjUDdw len=0 
' 0018     20 LABEL : Cell Value, String Constant - wCnBc len=0 
' 0018     20 LABEL : Cell Value, String Constant - yqMEx len=0 
' 0018     26 LABEL : Cell Value, String Constant - YryVrzeOwqe len=0 
' 0018     27 LABEL : Cell Value, String Constant - ZaqwrkOZijiv 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 
... (truncated)

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