Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4dcefeb867ff4e30…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:33:28 Authoring application: Microsoft Excel First seen: 2021-10-12
MD5: 9ca099221e6e169057dfca4ca06fd608 SHA-1: 23111897841c231d8c5ff8c75511cb0eb51739dd SHA-256: 4dcefeb867ff4e30893ff5bf8b8727f8a57e2981b9b4b42d697629437d3314ca
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 method for executing malicious code upon opening the workbook. The critical heuristics indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting an attempt to run arbitrary commands or download further payloads. No specific IOCs 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) 6356 bytes
SHA-256: 60703c3bcfbc30ed952a8ff45315154f04d579bed3cf8f9e580e9735e5508e56
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 -  eOQ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C173 
' 0018     24 LABEL : Cell Value, String Constant - cCFYAwuJI len=0 
' 0018     26 LABEL : Cell Value, String Constant - duzuEHslcpM len=0 
' 0018     26 LABEL : Cell Value, String Constant - FWLLwCcXsPw len=0 
' 0018     21 LABEL : Cell Value, String Constant - gfWgNp len=0 
' 0018     24 LABEL : Cell Value, String Constant - IklRbphya len=0 
' 0018     23 LABEL : Cell Value, String Constant - irqXfmwy len=0 
' 0018     22 LABEL : Cell Value, String Constant - IwinXDF len=0 
' 0018     25 LABEL : Cell Value, String Constant - kOPhgVORnu len=0 
' 0018     22 LABEL : Cell Value, String Constant - lCeiNqR len=0 
' 0018     20 LABEL : Cell Value, String Constant - njRSQ len=0 
' 0018     27 LABEL : Cell Value, String Constant - osyXomXPJpil len=0 
' 0018     21 LABEL : Cell Value, String Constant - OvgJdQ len=0 
' 0018     24 LABEL : Cell Value, String Constant - PqCWPtdGv len=0 
' 0018     24 LABEL : Cell Value, String Constant - QeGSNwuNi len=0 
' 0018     23 LABEL : Cell Value, String Constant - QoUdSoFs len=0 
' 0018     21 LABEL : Cell Value, String Constant - SPKWuP len=0 
' 0018     20 LABEL : Cell Value, String Constant - TIwjA len=0 
' 0018     20 LABEL : Cell Value, String Constant - VaQsK len=0 
' 0018     24 LABEL : Cell Value, String Constant - WTwrQVJwv len=0 
' 0018     23 LABEL : Cell Value, String Constant - zLyEQKHt 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 
... (truncated)

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