An issue was discovered in OpenSSH 7.9. Due to the scp implementation being derived from 1983 rcp, the server chooses which files/directories are sent to the client. However, the scp client only performs cursory validation of the object name returned (only directory traversal attacks are prevented). A malicious scp server (or Man-in-The-Middle attacker) can overwrite arbitrary files in the scp client target directory. If recursive operation (-r) is performed, the server can manipulate subdirectories as well (for example, to overwrite the .ssh/authorized_keys file).

Like many other SSH implementations, Apache MINA SSHD suffered from the issue that is more widely known as CVE-2023-48795. An attacker that can intercept traffic between client and server could drop certain packets from the stream, potentially causing client and server to consequently end up with a connection for which some security features have been downgraded or disabled, aka a Terrapin attack The mitigations to prevent this type of attack were implemented in Apache MINA SSHD 2.12.0, both client and server side. Users are recommended to upgrade to at least this version. Note that both the client and the server implementation must have mitigations applied against this issue, otherwise the connection may still be affected.