Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4065a4387559aeff…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:29:20 Authoring application: Microsoft Excel First seen: 2021-09-16
MD5: 9294246b55ebabb10590cd12dd6c2452 SHA-1: 220d114608e0595e0fde4bea9ee21044449ba4eb SHA-256: 4065a4387559aeffa5bd139f30b6767675761471caddb69b5b83c9870059b4ab
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. Critical heuristics indicate the presence of an Auto_Open defined name and the use of dangerous formula APIs, specifically the RUN function. This suggests the macro is designed to execute automatically and likely download or run a secondary 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) 6557 bytes
SHA-256: 9828e98d1781acf130838094c214a417ebf581091d806d2cc332763f8632a3d3
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  qEafeGjZH
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E177 
' 0018     27 LABEL : Cell Value, String Constant - DlFvLDmfscfL len=0 
' 0018     21 LABEL : Cell Value, String Constant - FtyUGi len=0 
' 0018     24 LABEL : Cell Value, String Constant - GAWOuednH len=0 
' 0018     23 LABEL : Cell Value, String Constant - gAyrPRnL len=0 
' 0018     24 LABEL : Cell Value, String Constant - GrhPRiwMz len=0 
' 0018     24 LABEL : Cell Value, String Constant - JFufekxvu len=0 
' 0018     27 LABEL : Cell Value, String Constant - KSwuYfuVqStg len=0 
' 0018     25 LABEL : Cell Value, String Constant - lONydnpeZR len=0 
' 0018     21 LABEL : Cell Value, String Constant - LtbWbf len=0 
' 0018     21 LABEL : Cell Value, String Constant - NGsjzS len=0 
' 0018     27 LABEL : Cell Value, String Constant - pSSkZaOtqsyr len=0 
' 0018     23 LABEL : Cell Value, String Constant - QiBaXtSZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - RgPIYSgW len=0 
' 0018     21 LABEL : Cell Value, String Constant - rocJhf len=0 
' 0018     26 LABEL : Cell Value, String Constant - swmczTkPuhP len=0 
' 0018     20 LABEL : Cell Value, String Constant - ulsga len=0 
' 0018     21 LABEL : Cell Value, String Constant - vaiEtj len=0 
' 0018     23 LABEL : Cell Value, String Constant - vHmatmBQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - WBZieFn len=0 
' 0018     22 LABEL : Cell Value, String Constant - xZTBDBx 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     1
... (truncated)

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