OpenSSH < 2.1.1 UseLogin Local Privilege Escalation
High Nessus Network Monitor Plugin ID 1991
SynopsisThe remote host is vulnerable to a flaw that allows for the bypassing of authentication
DescriptionThe remote host is running a version of OpenSSH which is older than 2.1.1. If the UseLogin option is enabled, then sshd does not switch to the uid of the user logging in. Instead, sshd relies on login(1) to do the job. However, if the user specifies a command for remote execution, login(1) cannot be used and sshd fails to set the correct user id, so the command is run with the same privileges as sshd (usually root privileges).
Note: PVS has solely relied on the banner of the SSH client to perform this check. Any backported patches or workarounds such as recompiling or edited configurations are not observable through the banner.
SolutionUpgrade to OpenSSH 2.1.1 or higher.