Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 51fcccedc24aa82d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:38:22 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: 03d9e3a027330b60fd6031b1fc953a7f SHA-1: daa8f83013bcf88add2685d1a5e85e4dd15ede51 SHA-256: 51fcccedc24aa82da75f648c8d8c2e64a8bf00da140936dc461698a344b77b82
140 Risk Score

Malware Insights

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

Static analysis revealed the presence of Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. The macro sheet contains formulas that are flagged as dangerous, suggesting it's designed to execute arbitrary code. The primary function of these macros is likely to download and execute a secondary payload, a common technique for initial execution.

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) 6708 bytes
SHA-256: 9789388ffd433963c72dab8782b360618bc2a1f020bdcdfa95f57774abe238fb
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  qhzyCFK
' 0018     25 LABEL : Cell Value, String Constant - AfYwtsMKwA len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G147 
' 0018     22 LABEL : Cell Value, String Constant - bmuJtBR len=0 
' 0018     22 LABEL : Cell Value, String Constant - CraCZnt len=0 
' 0018     23 LABEL : Cell Value, String Constant - fiSkzTfN len=0 
' 0018     27 LABEL : Cell Value, String Constant - gANwHXIrvxJa len=0 
' 0018     27 LABEL : Cell Value, String Constant - gVoBTQLjueuB len=0 
' 0018     26 LABEL : Cell Value, String Constant - hvhMxSDXWqz len=0 
' 0018     23 LABEL : Cell Value, String Constant - HxwNbrqg len=0 
' 0018     22 LABEL : Cell Value, String Constant - hzdVIZd len=0 
' 0018     21 LABEL : Cell Value, String Constant - lJGxlL len=0 
' 0018     23 LABEL : Cell Value, String Constant - lmulhyli len=0 
' 0018     24 LABEL : Cell Value, String Constant - QNuEOaTkQ len=0 
' 0018     23 LABEL : Cell Value, String Constant - SKdqkyqG len=0 
' 0018     27 LABEL : Cell Value, String Constant - soNUeGpfNUXO len=0 
' 0018     23 LABEL : Cell Value, String Constant - wgeUXQdj len=0 
' 0018     24 LABEL : Cell Value, String Constant - wKDWxoGRX len=0 
' 0018     23 LABEL : Cell Value, String Constant - XyiTcgxg len=0 
' 0018     20 LABEL : Cell Value, String Constant - YOXSu len=0 
' 0018     20 LABEL : Cell Value, String Constant - ZBWqX len=0 
' 0018     25 LABEL : Cell Value, String Constant - zzHSVzvFOl 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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