CVE-2022-45047: Apache MINA SSHD: Java unsafe deserialization vulnerability

[Thomas Wolf <twolf () apache org>]

Severity: important

Description:

Class org.apache.sshd.server.keyprovider.SimpleGeneratorHostKeyProvider in Apache MINA SSHD <= 2.9.1 uses Java 
deserialization to load a serialized java.security.PrivateKey. The class is one of several implementations that an 
implementor using Apache MINA SSHD can choose for loading the host keys of an SSH server.

Mitigation:

For Apache MINA SSHD <= 2.9.1, do not use org.apache.sshd.server.keyprovider.SimpleGeneratorHostKeyProvider to generate 
and later load your server's host key. Use separately generated host key files, for instance in OpenSSH format, and 
load them via a org.apache.sshd.common.keyprovider.FileKeyPairProvider instead. Or use a custom implementation instead 
of SimpleGeneratorHostKeyProvider that uses the OpenSSH format for storing and loading the host key (via classes 
OpenSSHKeyPairResourceWriter and OpenSSHKeyPairResourceParser).

The issue was fixed in Apache MINA SSHD 2.9.2. 

Credit:

The Apache MINA SSHD team would like to thank Zhang Zewei, NOFOCUS, for reporting this issue.