Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d7fa4b90a5bf9c21…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:42:15 Authoring application: Microsoft Excel First seen: 2021-10-12
MD5: ffdc347e109a894ef1652657e9325a3d SHA-1: 064fea95d8e9ac9df74794e7757ab7118623775e SHA-256: d7fa4b90a5bf9c218e606c97bd4c1761caeb94e867b647cb47fdcac20c729797
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 defined name, which is a critical indicator of malicious intent. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code. The macro sheet likely serves as a loader for a second-stage payload, although the specific download URL or execution command is not directly visible in the provided 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) 6590 bytes
SHA-256: 210e758c7ddda8dcf8c62d8195dafcbaf943d2bab74c96ed3dc48031455ec372
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 -  mNNKsbcv
' 0018     23 LABEL : Cell Value, String Constant - aIABAACC len=0 
' 0018     24 LABEL : Cell Value, String Constant - aNRnUsGCL len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H133 
' 0018     24 LABEL : Cell Value, String Constant - bhGiDrCcL len=0 
' 0018     27 LABEL : Cell Value, String Constant - CFzTXtPwitwN len=0 
' 0018     21 LABEL : Cell Value, String Constant - FpiJUj len=0 
' 0018     22 LABEL : Cell Value, String Constant - GmsvlaF len=0 
' 0018     26 LABEL : Cell Value, String Constant - iLYWaLHkVYY len=0 
' 0018     22 LABEL : Cell Value, String Constant - jiBttOu len=0 
' 0018     26 LABEL : Cell Value, String Constant - kbWFVKYcgUr len=0 
' 0018     22 LABEL : Cell Value, String Constant - kqGkdih len=0 
' 0018     20 LABEL : Cell Value, String Constant - nOBAN len=0 
' 0018     22 LABEL : Cell Value, String Constant - OFIUOfP len=0 
' 0018     23 LABEL : Cell Value, String Constant - OZIkjXTZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - pIuAGDLtvk len=0 
' 0018     26 LABEL : Cell Value, String Constant - shfydWdhxNo len=0 
' 0018     23 LABEL : Cell Value, String Constant - SYBDOlER len=0 
' 0018     27 LABEL : Cell Value, String Constant - uEPcaVFUHVPw len=0 
' 0018     20 LABEL : Cell Value, String Constant - YVnur len=0 
' 0018     24 LABEL : Cell Value, String Constant - zfJIhkkiZ len=0 
' 0018     24 LABEL : Cell Value, String Constant - ziYzjZeNA 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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