Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 99371d0f5ccf1c0a…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:44:13 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 08108a44be159912092f8bb2156daa33 SHA-1: 53639ade49234a4dff8c7dd5f36c28b7a46929fc SHA-256: 99371d0f5ccf1c0aedefd3ec6e35e6cae33357ed42e5f4a02be63a1da1d8d7e7
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-enabled workbook containing an Auto_Open function, which is a known technique for executing malicious code upon opening. The heuristics indicate the use of dangerous formula APIs within the macro, suggesting it is designed to download and execute a secondary payload. No specific family could be identified.

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) 6565 bytes
SHA-256: 6cf5080e40b2527042d9afbad89f5ea80ac8380961d511947269a6c9f25960cf
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  ukwpPCH
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E135 
' 0018     25 LABEL : Cell Value, String Constant - AwMoxLwUwg len=0 
' 0018     20 LABEL : Cell Value, String Constant - bXeyr len=0 
' 0018     24 LABEL : Cell Value, String Constant - CWhqvYbXt len=0 
' 0018     21 LABEL : Cell Value, String Constant - drAFDP len=0 
' 0018     22 LABEL : Cell Value, String Constant - graYmed len=0 
' 0018     25 LABEL : Cell Value, String Constant - HhcsaqpXNS len=0 
' 0018     25 LABEL : Cell Value, String Constant - hRUZTaTHJX len=0 
' 0018     26 LABEL : Cell Value, String Constant - HtGlkkoQwUH len=0 
' 0018     25 LABEL : Cell Value, String Constant - jYjhAzXAqK len=0 
' 0018     25 LABEL : Cell Value, String Constant - maeGZXFehn len=0 
' 0018     23 LABEL : Cell Value, String Constant - pRqRZlSD len=0 
' 0018     21 LABEL : Cell Value, String Constant - qYcofp len=0 
' 0018     25 LABEL : Cell Value, String Constant - sQapQECVXf len=0 
' 0018     24 LABEL : Cell Value, String Constant - SWfazVXGR len=0 
' 0018     24 LABEL : Cell Value, String Constant - TfYFdubMs len=0 
' 0018     27 LABEL : Cell Value, String Constant - TkNbwcWIDwqH len=0 
' 0018     21 LABEL : Cell Value, String Constant - uSkzom len=0 
' 0018     21 LABEL : Cell Value, String Constant - WeXoEq len=0 
' 0018     22 LABEL : Cell Value, String Constant - woxIvvj len=0 
' 0018     23 LABEL : Cell Value, String Constant - xPKzqtRw 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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