Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8b2d912eef01d9b6…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:25:46 Authoring application: Microsoft Excel First seen: 2021-09-27
MD5: 389f92467b08f27528f570a4e3f42c96 SHA-1: 48d8445d81ebff2463f0ddbe6bfd964b6c331b59 SHA-256: 8b2d912eef01d9b613530ee14065947de05ec5f4e63556b6cd586a458d5162a6
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 that contains an Auto_Open defined name, indicating it will execute automatically upon opening. Heuristics indicate the use of dangerous formula APIs, specifically the RUN function, which is commonly used to execute arbitrary code. This suggests the macro is designed 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) 6490 bytes
SHA-256: 2759d218ce7fc011c425dfa5df6073c1d848bd1683caf61a7864d28d7096b9c2
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 -  gHy
' 0018     20 LABEL : Cell Value, String Constant - AMoja len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H150 
' 0018     25 LABEL : Cell Value, String Constant - BtfoYwfEnv len=0 
' 0018     27 LABEL : Cell Value, String Constant - gKBXhIYAVNAa len=0 
' 0018     21 LABEL : Cell Value, String Constant - NFNOnL len=0 
' 0018     26 LABEL : Cell Value, String Constant - OeCbgHzKnwz len=0 
' 0018     21 LABEL : Cell Value, String Constant - OUFBnH len=0 
' 0018     27 LABEL : Cell Value, String Constant - piJnmjaNkfok len=0 
' 0018     23 LABEL : Cell Value, String Constant - pKQvgvGU len=0 
' 0018     26 LABEL : Cell Value, String Constant - PmtOCORqkal len=0 
' 0018     21 LABEL : Cell Value, String Constant - PSnajB len=0 
' 0018     24 LABEL : Cell Value, String Constant - qcZXrVtNH len=0 
' 0018     25 LABEL : Cell Value, String Constant - snBuXtFqHc len=0 
' 0018     26 LABEL : Cell Value, String Constant - spZmEyNipUL len=0 
' 0018     23 LABEL : Cell Value, String Constant - uwCUPqDV len=0 
' 0018     26 LABEL : Cell Value, String Constant - VcAqrHHPXfj len=0 
' 0018     24 LABEL : Cell Value, String Constant - vqsjuenGR len=0 
' 0018     23 LABEL : Cell Value, String Constant - vuhZzZpe len=0 
' 0018     23 LABEL : Cell Value, String Constant - XoebQKBO len=0 
' 0018     21 LABEL : Cell Value, String Constant - XXfhJn len=0 
' 0018     23 LABEL : Cell Value, String Constant - YsbfEWDO 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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