CVSS 6.8 CVE-2019-6109
CVSS 6.8 CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
An issue was discovered in OpenSSH 7.9. Due to missing character encoding in the progress display, a malicious server (or Man-in-The-Middle attacker) can employ crafted object names to manipulate the client output, e.g., by using ANSI control codes to hide additional files being transferred. This affects refresh_progress_meter() in progressmeter.c.
Test with SSH-MITM
A proof of concept exploit is integrated in ssh-mitm.
This exploit also integrates CVE-2019-6111 to inject additional files.
To inject files during a file transfer from the server to the client you have to start ssh-mitm with following arguments:
$ ssh-mitm server --scp-interface inject_file --scp-inject /path/to/additional/file
The file transfer for the injected file will be hidden because of the described vulnerability and CVE-2019-6110.