Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a1e5063367c19638…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:45:25 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 110827a1cfdf88c4325f5b066e249fd2 SHA-1: 83fb8035a739f0e3006b45394a619fdf99fca947 SHA-256: a1e5063367c19638a5b4ff3a6f9c1a834ed0f4f94e71bdd0f7d19def29f9af8d
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 (XLM) macros. A critical heuristic identified an Auto_Open defined name, indicating that the macro will execute automatically when the workbook is opened. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code, likely to download and run a second-stage payload.

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) 6624 bytes
SHA-256: 5a9656f1e9caa7b16600899ef86c1d8fb01d743bc85685d94beb94319f282ccf
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Nvuli
' 0018     20 LABEL : Cell Value, String Constant - acUQw len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A154 
' 0018     21 LABEL : Cell Value, String Constant - cukfcw len=0 
' 0018     21 LABEL : Cell Value, String Constant - dJkRVx len=0 
' 0018     23 LABEL : Cell Value, String Constant - jDGBbouL len=0 
' 0018     25 LABEL : Cell Value, String Constant - KikpbiXeBe len=0 
' 0018     26 LABEL : Cell Value, String Constant - kRyjjMPJbmd len=0 
' 0018     27 LABEL : Cell Value, String Constant - mJdWvbWhWzgo len=0 
' 0018     26 LABEL : Cell Value, String Constant - mjzpVNJaMLZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - NkdoQWMkXX len=0 
' 0018     23 LABEL : Cell Value, String Constant - nmBaDUNB len=0 
' 0018     26 LABEL : Cell Value, String Constant - OFkaPbwlHvq len=0 
' 0018     25 LABEL : Cell Value, String Constant - rNehVyecAE len=0 
' 0018     22 LABEL : Cell Value, String Constant - RsZZIIJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - skbaZi len=0 
' 0018     23 LABEL : Cell Value, String Constant - TpLzlKEG len=0 
' 0018     20 LABEL : Cell Value, String Constant - tYzkz len=0 
' 0018     20 LABEL : Cell Value, String Constant - UNEpS len=0 
' 0018     24 LABEL : Cell Value, String Constant - XLjhctaAZ len=0 
' 0018     26 LABEL : Cell Value, String Constant - zBKylIfOnBc len=0 
' 0018     27 LABEL : Cell Value, String Constant - zCjcTlAltRlV 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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