Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a04329ae761397b2…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:45:42 Authoring application: Microsoft Excel First seen: 2021-05-26
MD5: bc7bfae85db7607560e04d8ccd8958b2 SHA-1: a60af7647afe8d22a38057855465f4a3129df398 SHA-256: a04329ae761397b23d88548ccded2fb0168ccb64fa56695fb1291da1c347eb2a
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro sheet containing an Auto_Open function, which is a critical indicator of malicious intent. This function is designed to execute arbitrary code upon opening the workbook. The presence of dangerous formula APIs like RUN further confirms its malicious nature, suggesting it's used to download and execute 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) 6571 bytes
SHA-256: 6ac08b6e05ff9f5a601556079fd724f9401a4f9ce09313c620336cc086329a0d
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  TKZWoTfDYo
' 0018     27 LABEL : Cell Value, String Constant - afOpVLYwMhao len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E137 
' 0018     23 LABEL : Cell Value, String Constant - BrUQjMgD len=0 
' 0018     22 LABEL : Cell Value, String Constant - cPKOBpQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - DUUGZPK len=0 
' 0018     25 LABEL : Cell Value, String Constant - FpbFQIQGKe len=0 
' 0018     22 LABEL : Cell Value, String Constant - GlEnOKb len=0 
' 0018     25 LABEL : Cell Value, String Constant - iflcSLNbYa len=0 
' 0018     23 LABEL : Cell Value, String Constant - ljUixrMB len=0 
' 0018     21 LABEL : Cell Value, String Constant - muAJEq len=0 
' 0018     26 LABEL : Cell Value, String Constant - ngsgylCOTCS len=0 
' 0018     26 LABEL : Cell Value, String Constant - PhVoiLVrJjf len=0 
' 0018     23 LABEL : Cell Value, String Constant - TBnzPWoy len=0 
' 0018     22 LABEL : Cell Value, String Constant - tVSDpWO len=0 
' 0018     27 LABEL : Cell Value, String Constant - uuQGWedVjghG len=0 
' 0018     22 LABEL : Cell Value, String Constant - WUZGqpe len=0 
' 0018     20 LABEL : Cell Value, String Constant - xbEjA len=0 
' 0018     21 LABEL : Cell Value, String Constant - XLzlXn len=0 
' 0018     20 LABEL : Cell Value, String Constant - xsidH len=0 
' 0018     21 LABEL : Cell Value, String Constant - YFfTnr len=0 
' 0018     26 LABEL : Cell Value, String Constant - zfpyAQetGVM 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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