Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a6dbf890b61e2ad1…

MALICIOUS

Office (OLE)

37.0 KB Created: 2020-11-27 11:40:42 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: db28751cb7ea319d041df228867c722b SHA-1: 1acb024787a37cdd971f028e8e5c78b04cac3590 SHA-256: a6dbf890b61e2ad1883ef7b6380f4f8e78913369e0b002ca55fddc1124e0cc3b
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 method for executing malicious code upon opening the workbook. The macro sheet contains a reference to 'Auto_Open', suggesting it will automatically run when the file is opened. This is a common technique for delivering secondary payloads.

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) 6968 bytes
SHA-256: 614e3f3dbbe11938144d6dbd18b54394159fe53236ed7a408f83abb01aeb17f7
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 -  izdsTDVkghM
' 0018     20 LABEL : Cell Value, String Constant - afkXa len=0 
' 0018     25 LABEL : Cell Value, String Constant - afShZRqIHL len=0 
' 0018     26 LABEL : Cell Value, String Constant - aGYFlpNWwyo len=0 
' 0018     24 LABEL : Cell Value, String Constant - AlRvkbdUJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H152 
' 0018     20 LABEL : Cell Value, String Constant - avwCm len=0 
' 0018     22 LABEL : Cell Value, String Constant - cMcJykv len=0 
' 0018     26 LABEL : Cell Value, String Constant - dCXCAVQOgsl len=0 
' 0018     23 LABEL : Cell Value, String Constant - DoMSlUpe len=0 
' 0018     20 LABEL : Cell Value, String Constant - eAqoC len=0 
' 0018     22 LABEL : Cell Value, String Constant - FmtIYUb len=0 
' 0018     21 LABEL : Cell Value, String Constant - nVCQmI len=0 
' 0018     22 LABEL : Cell Value, String Constant - qSQeLcW len=0 
' 0018     27 LABEL : Cell Value, String Constant - sztLsylBwiYk len=0 
' 0018     26 LABEL : Cell Value, String Constant - WPzvfNBDJBI len=0 
' 0018     24 LABEL : Cell Value, String Constant - WrwZytvwm len=0 
' 0018     24 LABEL : Cell Value, String Constant - WukiUpktK len=0 
' 0018     24 LABEL : Cell Value, String Constant - xTdEjVAOs len=0 
' 0018     23 LABEL : Cell Value, String Constant - yqUHnKAp len=0 
' 0018     22 LABEL : Cell Value, String Constant - yuFFyaa len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZCUNKHgpRVE 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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