Medium [CVE-2020-15778] scp in OpenSSH through 8.3p1 allows command injection in the scp.c toremote function, as demonstrated by backtick characters in the destination argument

scp in OpenSSH through 8.3p1 allows command injection in the scp.c toremote function, as demonstrated by backtick characters in the destination argument.

NOTE: the vendor reportedly has stated that they intentionally omit validation of "anomalous argument transfers" because that could "stand a great chance of breaking existing workflows." A flaw was found in the scp program shipped with the openssh-clients package.

An attacker having the ability to scp files to a remote server, could execute arbitrary commands on the remote server by including the command as a part of the filename being copied on the server. This command is run with the permissions of user with which the files were copied on the remote server.

The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability depending on the default system umask and selinux policy/enforcement. This security flaw lies in the way scp command parses its command line arguments.

The SSH protocol or any other applications shipped as a part of openssh-clients packages are not vulnerable. In order to exploit this flaw, the attacker needs to social engineer or manipulate a system administrator (who has root access on the remote server) to run scp with a malicious command line parameter.