Hole in WS_FTP LE FTP client
A buffer overflow has been discovered in WS_FTP Light Edition, a popular free-of-charge FTP Client for Windows. Hackers can use it to gain control of a user's PC. An exploit is already circulating, but no patch has been released as yet.
The error is related to the processing of an FTP server's replies to PASV commands for switching from active to passive FTP. During active FTP, the server opens a connection to the client, which can cause problems with most Firewall configurations. For this reason most people tend to use passive FTP.
A rigged reply from the server to the PASV command allows malicious code to be written onto the stack of the user's PC and launched in the context of the user. For the attack to succeed, the hacker must have an FTP server under his control, although this is not a significant obstacle. The error was confirmed for WS_FTP LE 5.08, and other versions are likely similarly affected. Until an update is released, users should connect only to trusted servers or else use another product.