The most effective defense is upgrading to a modern version of OpenSSH (v9.0 or later). Recent versions use SFTP by default for file transfers, which does not suffer from these legacy RCP/SCP vulnerabilities.
Penetration testers targeting a server running OpenSSH 7.9p1 do not use a single magic script. They use a chain. openssh 7.9p1 exploit
So why does everyone search for this? Because OpenSSH has had terrifying bugs. CVE-2016-6210 (memory exhaustion). CVE-2018-15473 (user enum). But 7.9p1 sits in a sweet spot of "old enough to be vulnerable, new enough to have killed the low-hanging fruit." The most effective defense is upgrading to a
An attacker can overwrite critical files like .ssh/authorized_keys to gain persistent remote access to the client machine. They use a chain
To protect systems against these exploits, administrators should prioritize the following actions:
The OpenSSH project responded swiftly to the discovery of the vulnerability by releasing a patch, OpenSSH 7.9p1, which addresses the issue. System administrators and users are strongly advised to upgrade to the latest version of OpenSSH as soon as possible.