Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7e9bd6795ec43a3d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:33:29 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: deae44a8bf7c5a12eecb587d11d2232c SHA-1: f228f4ddfc235f1329aa412c4ad1b6535e32f5cf SHA-256: 7e9bd6795ec43a3d6de0cf63950e6b28bce82050882fb3a904cceeb2225c1d16
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, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code, likely to download and run a second-stage payload. No specific family could be identified, but the technique is common 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) 6629 bytes
SHA-256: 66bc4100d2d45dfc78fc9b310092a025bf3160fc14b0157c2be6a10e091b36b6
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  BwHqRtDjfYZ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C145 
' 0018     26 LABEL : Cell Value, String Constant - BeLVXEHSrNF len=0 
' 0018     23 LABEL : Cell Value, String Constant - BIxlxDYP len=0 
' 0018     22 LABEL : Cell Value, String Constant - dLkBCrV len=0 
' 0018     27 LABEL : Cell Value, String Constant - GKtGzmfNNtXa len=0 
' 0018     26 LABEL : Cell Value, String Constant - gzKojHvrOGY len=0 
' 0018     21 LABEL : Cell Value, String Constant - hpYIxS len=0 
' 0018     23 LABEL : Cell Value, String Constant - LYsGBLrZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - msAucHJL len=0 
' 0018     25 LABEL : Cell Value, String Constant - NwtbElrYXI len=0 
' 0018     23 LABEL : Cell Value, String Constant - qMxQVwgp len=0 
' 0018     22 LABEL : Cell Value, String Constant - QXFuBUy len=0 
' 0018     23 LABEL : Cell Value, String Constant - ScHzsbyj len=0 
' 0018     22 LABEL : Cell Value, String Constant - sKUJZnm len=0 
' 0018     20 LABEL : Cell Value, String Constant - SnbgM len=0 
' 0018     20 LABEL : Cell Value, String Constant - tfBaM len=0 
' 0018     20 LABEL : Cell Value, String Constant - VVjoE len=0 
' 0018     27 LABEL : Cell Value, String Constant - yNyLLgxxaVfd len=0 
' 0018     27 LABEL : Cell Value, String Constant - YzrNjZpSfOzT len=0 
' 0018     20 LABEL : Cell Value, String Constant - ZDnAb len=0 
' 0018     25 LABEL : Cell Value, String Constant - zhRbLGYZus 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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