Ubuntu 4.10 : openssh information leakage (USN-34-1)
Medium Nessus Plugin ID 20650
SynopsisThe remote Ubuntu host is missing one or more security-related patches.
Description@Mediaservice.net discovered two information leaks in the OpenSSH server. When using password authentication, an attacker could test whether a login name exists by measuring the time between failed login attempts, i. e. the time after which the 'password:' prompt appears again.
A similar issue affects systems which do not allow root logins over ssh ('PermitRootLogin no'). By measuring the time between login attempts an attacker could check whether a given root password is correct. This allowed determining weak root passwords using a brute force attack.
Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpdate the affected packages.