Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c84c97a430aad76e…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:45:11 Authoring application: Microsoft Excel First seen: 2021-07-07
MD5: 51920fba518f01b7d7d6b4c54ce7692d SHA-1: a784a94abf67a324d72a733845ba9c2c5f26d6db SHA-256: c84c97a430aad76ef3db77b668dfcff282a410b1f9ae8bad34b34a1fefb59593
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 that contains an Auto_Open macro. This macro is designed to execute dangerous formula APIs, specifically the RUN function, which is commonly used to launch external executables or scripts. The presence of the Auto_Open entry and the use of the RUN function strongly indicate that this macro sheet is intended to download and execute a secondary 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) 6648 bytes
SHA-256: 2fc7fdd04f49c6bdf03578821cf7218bf6863584692ba93448bf1931c9b56c64
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  sypiPsMDH
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H177 
' 0018     21 LABEL : Cell Value, String Constant - BNMUKz len=0 
' 0018     26 LABEL : Cell Value, String Constant - cQMbzNEnnrF len=0 
' 0018     25 LABEL : Cell Value, String Constant - cQMRHlsIei len=0 
' 0018     24 LABEL : Cell Value, String Constant - DAGpNqQpJ len=0 
' 0018     26 LABEL : Cell Value, String Constant - HHrhvwyidlZ len=0 
' 0018     27 LABEL : Cell Value, String Constant - hYNYilgmadvW len=0 
' 0018     21 LABEL : Cell Value, String Constant - jGPpwa len=0 
' 0018     27 LABEL : Cell Value, String Constant - jkOqmSBZwbKr len=0 
' 0018     20 LABEL : Cell Value, String Constant - nhBVZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - nYKUDor len=0 
' 0018     27 LABEL : Cell Value, String Constant - pUicniOObyGp len=0 
' 0018     26 LABEL : Cell Value, String Constant - rWVvxyUyIYy len=0 
' 0018     24 LABEL : Cell Value, String Constant - TPsybXPPM len=0 
' 0018     20 LABEL : Cell Value, String Constant - tRNTU len=0 
' 0018     23 LABEL : Cell Value, String Constant - TUTsCNKZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - UtLWiS len=0 
' 0018     25 LABEL : Cell Value, String Constant - uxfcUlEtvE len=0 
' 0018     22 LABEL : Cell Value, String Constant - vVYlvQe len=0 
' 0018     22 LABEL : Cell Value, String Constant - XyiWaVp len=0 
' 0018     26 LABEL : Cell Value, String Constant - YRJReHCdcGU 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
' 
... (truncated)

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