Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f9f5fcb278c25973…

MALICIOUS

Office (OLE)

37.0 KB Created: 2020-11-25 10:45:10 Authoring application: Microsoft Excel First seen: 2021-09-25
MD5: d709fd97dd5a847cba82a72cc6930e90 SHA-1: b6d7ff009270bd63bb6d511fb9e7094749171138 SHA-256: f9f5fcb278c25973c8f6908913b7362b0d59811c2e1f45b5fead930429973c51
140 Risk Score

Malware Insights

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

The file is an Excel macro-enabled document containing Excel 4.0 (XLM) macros. The presence of an Auto_Open defined name, coupled with the use of dangerous formula APIs like RUN, indicates that the macro is designed to execute arbitrary code upon opening. The specific payload or download mechanism is not detailed in the extracted evidence, but the intent is clearly malicious 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) 6615 bytes
SHA-256: c8c0001f4e2037e6563f69603c83374740a5a7e249c345d4a6ea40769dd5b208
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  aHyzBt
' 0018     25 LABEL : Cell Value, String Constant - AkQuSvIZyM len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A175 
' 0018     27 LABEL : Cell Value, String Constant - DqTSsbbMMFEZ len=0 
' 0018     26 LABEL : Cell Value, String Constant - EHlqzOZcgeM len=0 
' 0018     27 LABEL : Cell Value, String Constant - eKuAJzxtfpFo len=0 
' 0018     20 LABEL : Cell Value, String Constant - eyAjS len=0 
' 0018     23 LABEL : Cell Value, String Constant - fDxYvWXS len=0 
' 0018     27 LABEL : Cell Value, String Constant - HhSorVqpHyaR len=0 
' 0018     27 LABEL : Cell Value, String Constant - HKKaIfIIcvuz len=0 
' 0018     20 LABEL : Cell Value, String Constant - IIQvQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - KEwzprd len=0 
' 0018     25 LABEL : Cell Value, String Constant - KIFvzkZLqI len=0 
' 0018     25 LABEL : Cell Value, String Constant - KYbSuLsFzo len=0 
' 0018     22 LABEL : Cell Value, String Constant - PLZjXcQ len=0 
' 0018     26 LABEL : Cell Value, String Constant - qErEHWEpMMB len=0 
' 0018     24 LABEL : Cell Value, String Constant - QRBsIZpEh len=0 
' 0018     20 LABEL : Cell Value, String Constant - rwmSq len=0 
' 0018     22 LABEL : Cell Value, String Constant - TKIsMNG len=0 
' 0018     22 LABEL : Cell Value, String Constant - uJZTqtn len=0 
' 0018     22 LABEL : Cell Value, String Constant - WqPkgWA len=0 
' 0018     20 LABEL : Cell Value, String Constant - xALnX 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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