Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f777e3721ef3effa…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:45:40 Authoring application: Microsoft Excel First seen: 2021-09-15
MD5: 34296bf7ed15bd3d2f137e207dd0892e SHA-1: 176340fe7d8f4064461c837c8cef4652f420137e SHA-256: f777e3721ef3effa5740caa88256b1b6d147fd04fe80e7e63b8d829c55d0551b
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 known technique for executing malicious code upon opening the workbook. The heuristics indicate the use of dangerous formula APIs, specifically the RUN function, suggesting the macro is designed to execute an external command. This points to a macro-based downloader or dropper.

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) 6529 bytes
SHA-256: 960166d032ff902ceeea326f59df2c3595282f30442096547749902405ccbfba
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  WZLVzYO
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C165 
' 0018     23 LABEL : Cell Value, String Constant - DLxBXDwQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - DtqOV len=0 
' 0018     25 LABEL : Cell Value, String Constant - EgTzcMEGIS len=0 
' 0018     21 LABEL : Cell Value, String Constant - fLKTyv len=0 
' 0018     23 LABEL : Cell Value, String Constant - gcYWzhls len=0 
' 0018     23 LABEL : Cell Value, String Constant - kiqyExdj len=0 
' 0018     27 LABEL : Cell Value, String Constant - mKqPoWpeVCKN len=0 
' 0018     24 LABEL : Cell Value, String Constant - MniqydGdf len=0 
' 0018     25 LABEL : Cell Value, String Constant - NFBCepnkyY len=0 
' 0018     20 LABEL : Cell Value, String Constant - NVAsk len=0 
' 0018     23 LABEL : Cell Value, String Constant - OAIElBNV len=0 
' 0018     24 LABEL : Cell Value, String Constant - OYXkCKdDT len=0 
' 0018     20 LABEL : Cell Value, String Constant - rAfsG len=0 
' 0018     26 LABEL : Cell Value, String Constant - RFOxkqgpQoi len=0 
' 0018     27 LABEL : Cell Value, String Constant - RKUjgpzQwluG len=0 
' 0018     25 LABEL : Cell Value, String Constant - UaIAvidKeg len=0 
' 0018     26 LABEL : Cell Value, String Constant - vjFLygebvdl len=0 
' 0018     22 LABEL : Cell Value, String Constant - WMqGTtl len=0 
' 0018     25 LABEL : Cell Value, String Constant - WSjUhqMPxL len=0 
' 0018     27 LABEL : Cell Value, String Constant - wWWKXLpLFQjk 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
' 0
... (truncated)

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