CERN Accelerating science

Abstract

Off-site telnet access to CERN will be blocked on Tuesday 28th January 2003.

To reduce the number of regular break-ins on CERN machines due to passwords exposed on the network in clear text, OFF-SITE TELNET ACCESS TO CERN WILL BE BLOCKED in the CERN firewall from

Tuesday 28th January 2003

Users are recommended to install and use SSH (Secure SHell) as an alternative to both telnet and ftp as soon as possible for off and on site access. Further details are at:

http://cern.ch/security/ssh

In addition, please note the following:

• FTP also exposes passwords in clear text and is planned to be closed at a later date when alternatives are available for all services (e.g. NICE file servers and central web servers still require ftp). SSH (scp or sftp) provides similar file transfer functionality to ftp and is a recommended alternative where this is possible. It is more secure and with compression can also be more efficient.

• You are recommended to change passwords which could have been exposed by telnet and ftp as soon as you convert to SSH.

• ACB and VPN access are considered as if on site and are not affected by this telnet block. You are however strongly recommended to use SSH to access CERN systems for all connections, whether on or off site.