source: https://www.securityfocus.com/bid/5822/info

SafeTP is a freely available, open source secure ftp client-server software package. It is available for Unix, Linux, and Microsoft Operating Systems.

It has been reported that under some circumstances, the SafeTP server may reveal sensitive network information. When a passive session is initiated in a specific manner, SafeTP may return the address of a system serving files that is behind at NAT firewall.

220-SafeTP: Negotiating FTP connection...
220-safetp.nowhere.com X2 WS_FTP Server 3.1.0 (1506847632)
220-Changed to Protect the Innocent
220-safetp.nowhere.com X2 WS_FTP Server 3.1.0 (1506847632)
220-*** This server can accept secure (encrypted) connections. ***
220-*** See http://safetp.cs.berkeley.edu for info. ***
220 SafeTP: Control channel secure: X-SafeTP1. Data channel secure. PBSZ=32801b
Connected to safetp.nowhere.com.
User: SomeUser
331 Password required
Password: *********
230-user logged in
230-Hello Some User. Welcome to the SafeTP File Transfer System!
230 user logged in
ftp> ls
200 PORT command ok.
Timed out waiting for connection from server.
ftp> passive
Passive mode On .
ftp> ls
425 Failed to connect to 192.168.3.162, port 3303: connect: Connection timed out (code 10060)
ftp> passive
Draining: 510 Assertion failed: ftpd reply: 150 Opening ASCII data connection for directory listing
Draining: 227 Entering Passive Mode (10,7,34,85,5,133).
Passive mode Off .
ftp> put tendot.txt
227 Entering passive mode (169,229,60,94,156,186).
150 Opening ASCII data connection for tendot.txt
226 transfer complete
ftp: 1094 bytes sent in 0.98Seconds 1.09Kbytes/sec.
ftp> quit
221-Good-Bye
221-Goodbye Some User. Thank you for visiting the SafeTP File Transfer System!
221 Good-Bye