Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 55b7d672532a443d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:39:27 Authoring application: Microsoft Excel First seen: 2021-10-11
MD5: d98145837ea5f1a6ab48f9efb4f65f51 SHA-1: 9b591277a43fd819eb22d7bba61bc157adec72de SHA-256: 55b7d672532a443dabb17f5ae3e7b1205c4b9308f9b7e838b0fff8478aa97362
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, which is a known technique for executing malicious code. The macro sheet contains a call to a dangerous function (RUN=0), suggesting it is designed to execute a payload. No specific family could be identified, but the technique is common for initial execution.

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) 6687 bytes
SHA-256: be2dffbcf516233d7052e8c8d75ac22ce079431871b780f14f8e0caa733b8c97
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  iAsujYwUWbj
' 0018     22 LABEL : Cell Value, String Constant - aAtJzLB len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A161 
' 0018     20 LABEL : Cell Value, String Constant - czrRl len=0 
' 0018     23 LABEL : Cell Value, String Constant - ETbJxlqQ len=0 
' 0018     26 LABEL : Cell Value, String Constant - gcsBQxOgKWd len=0 
' 0018     22 LABEL : Cell Value, String Constant - gLoUHzp len=0 
' 0018     21 LABEL : Cell Value, String Constant - GUiAyO len=0 
' 0018     26 LABEL : Cell Value, String Constant - hVyakPLZCzW len=0 
' 0018     22 LABEL : Cell Value, String Constant - KEfirIY len=0 
' 0018     26 LABEL : Cell Value, String Constant - NkoHPDHdtTl len=0 
' 0018     24 LABEL : Cell Value, String Constant - oRPNZiDrp len=0 
' 0018     27 LABEL : Cell Value, String Constant - qiRtoakmKrsV len=0 
' 0018     22 LABEL : Cell Value, String Constant - QzRytDk len=0 
' 0018     27 LABEL : Cell Value, String Constant - rRNGDlJUKJcx len=0 
' 0018     21 LABEL : Cell Value, String Constant - SBnDQM len=0 
' 0018     25 LABEL : Cell Value, String Constant - SxIrRywUsG len=0 
' 0018     24 LABEL : Cell Value, String Constant - uttvAxHYW len=0 
' 0018     27 LABEL : Cell Value, String Constant - WfLvFaGohBit len=0 
' 0018     20 LABEL : Cell Value, String Constant - yDgXs len=0 
' 0018     20 LABEL : Cell Value, String Constant - YtqYe len=0 
' 0018     21 LABEL : Cell Value, String Constant - zdosvJ 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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