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OpenSSH < 2.1.1 UseLogin Local Privilege Escalation

High

Synopsis

The remote host is vulnerable to a flaw that allows for the bypassing of authentication

Description

The 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.

Solution

Upgrade to OpenSSH 2.1.1 or higher.