Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b144b3901dc8db9a…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:45:58 Authoring application: Microsoft Excel First seen: 2021-09-22
MD5: 190419b7c8d5e2f51c1197cb83ccaec2 SHA-1: c8e07652d6919bf2014d5b696a364c064ec551c1 SHA-256: b144b3901dc8db9a2ad470aed3aac93488f95e21eb272f00b721ca80bfa1284d
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a critical finding. The presence of dangerous formula APIs like RUN indicates the macro is designed to execute arbitrary code. While the exact payload is not visible, the structure strongly suggests it's a downloader for a secondary stage.

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) 6322 bytes
SHA-256: 2b746d3c91e09da008f2649cc8aad6a0e8cdcca2dea873f1c0637305bc0e25c8
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 -  XFg
' 0018     26 LABEL : Cell Value, String Constant - aJQOjVZKdng len=0 
' 0018     20 LABEL : Cell Value, String Constant - aqkKn len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A138 
' 0018     23 LABEL : Cell Value, String Constant - CDqmNSnF len=0 
' 0018     24 LABEL : Cell Value, String Constant - CrXoXINEg len=0 
' 0018     21 LABEL : Cell Value, String Constant - CVhGsg len=0 
' 0018     20 LABEL : Cell Value, String Constant - EYepB len=0 
' 0018     24 LABEL : Cell Value, String Constant - fQZWfUqIK len=0 
' 0018     20 LABEL : Cell Value, String Constant - GqkNi len=0 
' 0018     22 LABEL : Cell Value, String Constant - gXsNpag len=0 
' 0018     20 LABEL : Cell Value, String Constant - hlpqq len=0 
' 0018     24 LABEL : Cell Value, String Constant - hYlOEoxSM len=0 
' 0018     22 LABEL : Cell Value, String Constant - JKqPntK len=0 
' 0018     25 LABEL : Cell Value, String Constant - KjgvklyNtY len=0 
' 0018     27 LABEL : Cell Value, String Constant - MzakRHQHcVlA len=0 
' 0018     23 LABEL : Cell Value, String Constant - NqyNfZdi len=0 
' 0018     25 LABEL : Cell Value, String Constant - SbwjwNGOfP len=0 
' 0018     20 LABEL : Cell Value, String Constant - scyCm len=0 
' 0018     22 LABEL : Cell Value, String Constant - WEMvfiH len=0 
' 0018     25 LABEL : Cell Value, String Constant - wyuXjxWYIF len=0 
' 0018     20 LABEL : Cell Value, String Constant - YkItk 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 
... (truncated)

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