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ComSndFTP v1.3.7 Beta USER Format String (Write4) Vulnerability

This module exploits the ComSndFTP FTP Server version 1.3.7 beta by sending a specially crafted format string specifier as a username. The crafted username is sent to the server to overwrite the hardcoded function pointer from Ws2_32.dll!WSACleanup. Once this function pointer is triggered, the code bypasses dep and then repairs the pointer to execute arbitrary code. The SEH exit function is preferred so that the administrators are not left with an unhandled exception message. When using the meterpreter payload, the process will never die, allowing for continuous exploitation.

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Module Name



  • ChaoYi Huang <ChaoYi.Huang [at]>
  • rick2600 <rick2600 [at]>
  • mr_me <mr_me [at]>
  • corelanc0d3r < [at]>



  • Automatic
  • Windows XP SP3 - English
  • Windows Server 2003 - English


  • windows


  • x86



Module Options

To display the available options, load the module within the Metasploit console and run the commands 'show options' or 'show advanced':

msf > use exploit/windows/ftp/comsnd_ftpd_fmtstr msf exploit(comsnd_ftpd_fmtstr) > show targets ...targets... msf exploit(comsnd_ftpd_fmtstr) > set TARGET <target-id> msf exploit(comsnd_ftpd_fmtstr) > show options and set options... msf exploit(comsnd_ftpd_fmtstr) > exploit