Firewall Wizards mailing list archives
FTP Security
From: "Marcelo Barbosa Lima" <marcelo.lima () dcc unicamp br>
Date: Tue, 4 May 1999 13:55:04 -0300
Hi folks, I were reading one paper about security problems in FTP and did not undestand this: "When the data transfers are done in active mode, the attacker guesses the number of the TCP port where the target client will be doing a listen. He or she then repeatedly sends the ftp server to which the client is connected the commands PORT ip,of,client,machine,port,port RETR filename or STOR filename. Using RETR if he wishes to replace data transmitted to the client, and STOR if he is trying to intercept data the client would send to the server. " Do you agree with this? Well, i saw that the client sends his port number across the control connection using the PORT command. How can the atacker send (repeatdly) commands PORT to FTP server if he or she doesn't know TCP sequence numbers of the control connection between client and server? Another question is: how can the atacker know about the control connections in a particular FTP server? Netstat? I like your solutions for these problems! Sorry for my poor english :-). Thanks and Regards! Marcelo B. Lima marcelo.lima () dcc unicamp br
Current thread:
- FTP Security Marcelo Barbosa Lima (May 03)
- <Possible follow-ups>
- Re: FTP Security Bill_Royds (May 04)