Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 04caa4a172499203…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:33:01 Authoring application: Microsoft Excel First seen: 2021-10-14
MD5: dc00286d9b966d47cd172602ed1f5916 SHA-1: 29a7f82e2f042f038d459b1ca45d6c609cc6cbb6 SHA-256: 04caa4a172499203c26ccd8ce154aa961f1322b1215cd939b3d1f42ea014cc40
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 function, which is a known technique for executing malicious code upon opening the document. The critical heuristics indicate the presence of dangerous formula APIs within the macro, suggesting an attempt to exploit vulnerabilities or execute arbitrary commands. No specific IOCs like URLs or hashes were extracted, but the technique itself is highly suspicious.

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) 6420 bytes
SHA-256: b6916af94212d8a1a73bb45b1cc18694df57dd622ab0062e64053b1685b80d1b
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 -  kwlp
' 0018     21 LABEL : Cell Value, String Constant - AUkZUd len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G137 
' 0018     25 LABEL : Cell Value, String Constant - DkJkuOLFkz len=0 
' 0018     27 LABEL : Cell Value, String Constant - EsnkfuhkfaUN len=0 
' 0018     25 LABEL : Cell Value, String Constant - GbxpGUZQua len=0 
' 0018     20 LABEL : Cell Value, String Constant - gGUiT len=0 
' 0018     27 LABEL : Cell Value, String Constant - iEcFoHiUEnEy len=0 
' 0018     21 LABEL : Cell Value, String Constant - JeZgpO len=0 
' 0018     25 LABEL : Cell Value, String Constant - JKhccnUeao len=0 
' 0018     27 LABEL : Cell Value, String Constant - KKreXloTXikr len=0 
' 0018     20 LABEL : Cell Value, String Constant - mpdpS len=0 
' 0018     23 LABEL : Cell Value, String Constant - OWKciQqt len=0 
' 0018     26 LABEL : Cell Value, String Constant - QrZtaxpeTqO len=0 
' 0018     23 LABEL : Cell Value, String Constant - TauNArkM len=0 
' 0018     26 LABEL : Cell Value, String Constant - tuiveEceGQX len=0 
' 0018     21 LABEL : Cell Value, String Constant - twoGud len=0 
' 0018     20 LABEL : Cell Value, String Constant - TZuWT len=0 
' 0018     24 LABEL : Cell Value, String Constant - vHKZRATjL len=0 
' 0018     24 LABEL : Cell Value, String Constant - wabryjPLd len=0 
' 0018     25 LABEL : Cell Value, String Constant - xTOACQPXJf len=0 
' 0018     24 LABEL : Cell Value, String Constant - yeLeTkBpj 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  
... (truncated)

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