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).

An issue was discovered in the Amazon Linux packages of OpenSSH 7.4 for Amazon Linux 1 and 2, because of an incomplete fix for CVE-2019-6111 within these specific packages. The fix had only covered cases where an absolute path is passed to scp. When a relative path is used, there is no verification that the name of a file received by the client matches the file requested. Fixed packages are available with numbers 7.4p1-22.78.amzn1 and 7.4p1-22.amzn2.0.2.

An issue was discovered in rcp in MIT krb5-appl through 1.0.3. Due to the rcp implementation being derived from 1983 rcp, the server chooses which files/directories are sent to the client. However, the rcp client only performs cursory validation of the object name returned (only directory traversal attacks are prevented). A malicious rcp server (or Man-in-The-Middle attacker) can overwrite arbitrary files in the rcp 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). This issue is similar to CVE-2019-6111 and CVE-2019-7283. NOTE: MIT krb5-appl is not supported upstream but is shipped by a few Linux distributions. The affected code was removed from the supported MIT Kerberos 5 (aka krb5) product many years ago, at version 1.8.

An issue was discovered in rcp in NetKit through 0.17. For an rcp operation, the server chooses which files/directories are sent to the client. However, the rcp client only performs cursory validation of the object name returned. A malicious rsh server (or Man-in-The-Middle attacker) can overwrite arbitrary files in a directory on the rcp client machine. This is similar to CVE-2019-6111.