SSH Host Key Sharing Vulnerability in Cloud-init by Canonical

CVE-2018-10896

Summary

A security issue exists in Cloud-init versions 0.6.2 and later due to the default configuration that allows the persistence of SSH host keys across cloned instances. The configuration option 'ssh_deletekeys: 0' prevents the deletion of SSH host keys by cloud-init, which can lead to multiple instances derived from a gold template sharing identical SSH keys. This raises significant security risks, including the potential for instances to impersonate each other and execute man-in-the-middle attacks, thus compromising the integrity and security of communications between instances.

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