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OpenSSH < 2.9.9 Multiple Key Type ACL Bypass

Medium

Synopsis

Remote users may be able to circumvent system policy.

Description

The remote host is running a version of OpenSSH between 2.5.x and 2.9.x. Depending on the order of the user keys in ~/.ssh/authorized_keys2, sshd might fail to apply the source IP based access control restriction to the correct key. This problem allows users to circumvent the system policy and login from disallowed source IP address.

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 2.9.9 or higher.