Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fb96e630c4a7d260…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:43:54 Authoring application: Microsoft Excel First seen: 2020-12-25
MD5: 5e3ce471bc0e02c492b55ba3b7a8d91d SHA-1: ef6cda2733bf44a466138254e9d38cf6aa2422c0 SHA-256: fb96e630c4a7d260395294fb00e6f45e88c9a764ccbf86d2f068c0263155cfbb
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 macros, specifically an Auto_Open function. This function is known to be used for executing malicious code upon opening the document. The presence of dangerous formula APIs in the Auto_Open macro indicates an intent to run arbitrary commands, likely for downloading and executing a secondary 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) 6655 bytes
SHA-256: 50a16dd3a4f16dec3a8f637e0ee7a9e4fd7c27e5ebaa30b9555409d515edb7f4
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 -  bcRXZeEFCpp
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D148 
' 0018     20 LABEL : Cell Value, String Constant - bdHIH len=0 
' 0018     27 LABEL : Cell Value, String Constant - BGvuYDSAWzXX len=0 
' 0018     27 LABEL : Cell Value, String Constant - buTyaSrjONPK len=0 
' 0018     24 LABEL : Cell Value, String Constant - BVzEuyYCu len=0 
' 0018     21 LABEL : Cell Value, String Constant - DFCFPu len=0 
' 0018     20 LABEL : Cell Value, String Constant - ewVVP len=0 
' 0018     25 LABEL : Cell Value, String Constant - GhCMTGznHh len=0 
' 0018     26 LABEL : Cell Value, String Constant - gVIrDPtNosm len=0 
' 0018     25 LABEL : Cell Value, String Constant - jawoHkCxMn len=0 
' 0018     21 LABEL : Cell Value, String Constant - lAmRWa len=0 
' 0018     24 LABEL : Cell Value, String Constant - mBcEqcWLz len=0 
' 0018     20 LABEL : Cell Value, String Constant - pLMbK len=0 
' 0018     27 LABEL : Cell Value, String Constant - qfjHwtEuwbpA len=0 
' 0018     25 LABEL : Cell Value, String Constant - RQLuQOdwRN len=0 
' 0018     27 LABEL : Cell Value, String Constant - vBZBjZcDbheL len=0 
' 0018     22 LABEL : Cell Value, String Constant - vwKsScZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - WLTYDt len=0 
' 0018     27 LABEL : Cell Value, String Constant - wYamTHpdJiCd len=0 
' 0018     20 LABEL : Cell Value, String Constant - XxVHV len=0 
' 0018     24 LABEL : Cell Value, String Constant - YUwBgzktt 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
' 
... (truncated)

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