Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 5177e512ef08cef3…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:45:42 Authoring application: Microsoft Excel First seen: 2021-11-02
MD5: 8bdf822d041f24639dff062aec1efa33 SHA-1: 31e8164ac6fc7f3270512a79f2292d6997dff6e1 SHA-256: 5177e512ef08cef32db0d0acf6479d387817f3b4ab0c9f21d976b9f85810ecdf
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-enabled workbook containing an Auto_Open function. This function is designed to execute arbitrary commands, indicated by the presence of dangerous formula APIs like RUN. The macro sheet itself contains obfuscated data, suggesting an attempt to hide malicious code. The primary purpose is likely to download and execute 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) 6691 bytes
SHA-256: 3012985e3ac7c9150579fc156271d6f79649e37411973806897ba5566d6921ad
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 -  dWJjdG
' 0018     27 LABEL : Cell Value, String Constant - AFsxcmztbTiX len=0 
' 0018     24 LABEL : Cell Value, String Constant - ANMApSbMI len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A181 
' 0018     24 LABEL : Cell Value, String Constant - ByrKlOpQJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - cOAzLBg len=0 
' 0018     25 LABEL : Cell Value, String Constant - dOspuLFoIf len=0 
' 0018     20 LABEL : Cell Value, String Constant - DRufv len=0 
' 0018     23 LABEL : Cell Value, String Constant - DtGCocHG len=0 
' 0018     20 LABEL : Cell Value, String Constant - glrmq len=0 
' 0018     24 LABEL : Cell Value, String Constant - hGaRULhpi len=0 
' 0018     24 LABEL : Cell Value, String Constant - hibuKHtkB len=0 
' 0018     23 LABEL : Cell Value, String Constant - jVdodHZW len=0 
' 0018     22 LABEL : Cell Value, String Constant - lKjUbMU len=0 
' 0018     27 LABEL : Cell Value, String Constant - NEuxYBgVMclX len=0 
' 0018     27 LABEL : Cell Value, String Constant - NVRvbcVqMcln len=0 
' 0018     20 LABEL : Cell Value, String Constant - OCodI len=0 
' 0018     25 LABEL : Cell Value, String Constant - QWSNaOPqqA len=0 
' 0018     26 LABEL : Cell Value, String Constant - rmnZmrLyrKd len=0 
' 0018     20 LABEL : Cell Value, String Constant - ujKjF len=0 
' 0018     25 LABEL : Cell Value, String Constant - VtcCrXeXXl len=0 
' 0018     24 LABEL : Cell Value, String Constant - XNIJchXdS 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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