Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 31a25037593785c6…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:45:20 Authoring application: Microsoft Excel First seen: 2021-09-23
MD5: 95207701fdf19c936358d0cf1ed3a9ce SHA-1: f131c814d2a8c0779db560bdc138460bbcc93bf8 SHA-256: 31a25037593785c6a13c42b3aa05afd0298f7635b145ca3b35aae5e0111b505f
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name and dangerous formula APIs, specifically the RUN function. This strongly suggests the macro is designed to execute arbitrary code upon opening the document. While no specific URLs or payloads were extracted, the pattern is typical for macro-based malware that downloads and executes 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) 6435 bytes
SHA-256: 4b9f33bb6f08b4444555f79798cf852093cfa7607025b668aa5f10f4d4005f83
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  zZr
' 0018     21 LABEL : Cell Value, String Constant - asGSQp len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E145 
' 0018     23 LABEL : Cell Value, String Constant - BafqQZAk len=0 
' 0018     23 LABEL : Cell Value, String Constant - cElfdfgw len=0 
' 0018     25 LABEL : Cell Value, String Constant - CfIRGpYGnF len=0 
' 0018     22 LABEL : Cell Value, String Constant - CpZKfsQ len=0 
' 0018     27 LABEL : Cell Value, String Constant - eLERBKOiUJUo len=0 
' 0018     26 LABEL : Cell Value, String Constant - FesioMaxKck len=0 
' 0018     23 LABEL : Cell Value, String Constant - GTJIIJKk len=0 
' 0018     22 LABEL : Cell Value, String Constant - HgmkrcM len=0 
' 0018     26 LABEL : Cell Value, String Constant - hhbjRAXWzkI len=0 
' 0018     27 LABEL : Cell Value, String Constant - HhMStBGcEAFD len=0 
' 0018     23 LABEL : Cell Value, String Constant - irXiMrLw len=0 
' 0018     23 LABEL : Cell Value, String Constant - jTGNXSYA len=0 
' 0018     27 LABEL : Cell Value, String Constant - NZALRZGcBsdk len=0 
' 0018     21 LABEL : Cell Value, String Constant - omwJUK len=0 
' 0018     25 LABEL : Cell Value, String Constant - oOfGvsBbWl len=0 
' 0018     25 LABEL : Cell Value, String Constant - SKkzRHyWxJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - TVTKsY len=0 
' 0018     24 LABEL : Cell Value, String Constant - UslxqJNKA len=0 
' 0018     20 LABEL : Cell Value, String Constant - WiTuB 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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