Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a59739b786801bb7…

MALICIOUS

Office (OLE)

231.5 KB Created: 2020-05-15 06:56:49 Authoring application: Microsoft Excel First seen: 2020-09-07
MD5: 3b2f4871e2665261ef90082f24c18ccb SHA-1: 439ff57248460bb7371ecf5bc999a1aae5a79434 SHA-256: a59739b786801bb714876be720787b6fc0754b35c26386e62472cc5af7171947
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The critical heuristics indicate the presence of an obfuscated Excel 4.0 Auto_Open macro. This macro is designed to execute arbitrary commands, as evidenced by the RUN and SET.VALUE functions found within the macro code. The specific commands suggest an attempt to download and execute a secondary payload or perform other malicious actions.

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) 128083 bytes
SHA-256: 9badd581559f008a5305616944ebdb2bca4e4de311aed15ef513974c1a338758
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!FU48385 
' 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,BX37,"",-0.59821428571428569843
'  Sheet,IC37,"",0.40983606557377050272
'  Sheet,CN63,"",-1.46268656716417910779
'  Sheet,K121,"",-5.50000000000000000000
'  Sheet,IN181,"",5.62962962962962976121
'  Sheet,ET216,"",0.22252747252747251405
'  Sheet,X243,"",36.75000000000000000000
'  Sheet,CJ267,"",99.00000000000000000000
'  Sheet,HY279,"",-4.01960784313725483230
'  Sheet,G288,"",-199.00000000000000000000
'  Sheet,GV333,"",28.40001953124999900524
'  Sheet,IS344,"",249.00000000000000000000
'  Sheet,CL376,"",0.11750599520383693541
'  Sheet,FI404,"",5.54545454545454585826
'  Sheet,DY424,"",199.00000000000000000000
'  Sheet,BE462,"",1399.00000000000000000000
'  Sheet,F475,"",-0.17454545454545455918
'  Sheet,DW503,"",385.00000000000000000000
'  Sheet,JJ504,"",0.68985507246376809309
'  Sheet,JI511,"",-58.75000000000000000000
'  Sheet,IQ513,"",-1396.00000000000000000000
'  Sheet,JC520,"",2025.50000000000000000000
'  Sheet,BK529,"",-1.31081081081081074480
'  Sheet,CB590,"",-0.24878048780487804770
'  Sheet,DQ694,"",129.00000000000000000000
'  Sheet,I699,"",-30.50000000000000000000
'  Sheet,JN724,"",-11.06250000000000000000
'  Sheet,HH772,"",-13.69387755102040848953
'  Sheet,IR868,"SET.VALUE(ED7830,-56.00000000000000000000-GET.CELL(17,Q63109))",""
'  Sheet,IR869,RUN(EO37822),""
'  Sheet,HS936,"",-1.55223880597014929350
'  Sheet,R969,"",0.58048680487804882322
'  Sheet,JQ999,"",-355.00000000000000000000
'  Sheet,CN1000,"",-130.00000000000000000000
'  Sheet,FM1023,"",5.54545454545454585826
'  Sheet,HY1028,"",436.00000000000000000000
'  Sheet,IY1067,"",411.00000000000000000000
'  Sheet,DC1068,"",0.38121546961325969427
'  Sheet,HN1076,"",0.97142857142857141906
'  Sheet,GO1095,"",316.00000000000000000000
'  Sheet,GF1110,"",-762.00000000000000000000
'  Sheet,IW1116,"",-424.00000000000000000000
'  Sheet,GE1261,"",-958.00000000000000000000
'  Sheet,U1271,"",0.13934426229508195538
'  Sheet,F1292,"",-335.00000000000000000000
'  Sheet,P1297,"",-125.00000000000000000000
'  Sheet,CB1310,"",324.00000000000000000000
'  Sheet,BU1316,"",-147.00000000000000000000
'  Sheet,CH1428,"",-140.00000000000000000000
'  Sheet,IA1439,"",-296.00000000000000000000
'  Sheet,EI1458,"",2.70967741935483852345
'  Sheet,CX1459,"",2073.50000000000000000000
'  Sheet,JQ1500,"",13.75000000000000000000
'  Sheet,EO1561,"",-465.00000000000000000000
'  Sheet,CK1663,"",-1.45454545454545458583
'  Sheet,HD1685,"",199.00000000000000000000
'  Sheet,DY1721,"",2.70149253731343286233
'  Sheet,JB1728,"",-1.23750061035156244671
'  Sheet,BE1729,"",-1.60000000000000142109
'  Sheet,IT1738,"",2.36134453781512609893
'  Sheet,IS1758,"",108.00000000000000000000
'  Sheet,BD1767,"",-203.00000000000000000000
'  Sheet,IB1818,"",0.60220994475138123203
'  Sheet,HQ1841,"",2010.50000000000000000000
'  Sheet,BZ1889,"",-0.02234069560802234150
'  Sheet,EL1910,"",0.06506506506506506970
'  Sheet,H1929,"",8.26470588235294201240
'  Sheet,HN1938,"",-12.09009009009009005808
'  Sheet,DL1954,"",373.00000000000000000000
'  Sheet,II1959,"",-309.00000000000000000000
'  Sheet,G1983,"",0.86545454545454547635
'  Sheet,CG1985,"",3.34246575342465757075
'  Sheet,EV2001,"",5.54545454545454585826
'  Sheet,A2041,"",-0.40363636363636362647
'  Sheet,HS2059,"",699.00000000000000000000
'  Sheet,IA2120,"",-1.73134428358208936061
'  Sheet,F2126,"",2.10084033613445386734
'  Sheet,EO2173,"",140.00000000000000000000
'  Sheet,JN2175,"",1.82773109243697473580
'  Sheet,BY2234,"",-0.75257731958762885682
'  Sheet,IE2298,"",199.00000000000000000000
'  Sheet,IH2300,"",-268.00000000000000000000
'  Sheet,BE2447,"",-139.00000000000000000000
'  Sheet,CE2469,
... (truncated)