Ruby before 2.4.3 allows Net::FTP command injection. Net::FTP#get, getbinaryfile, gettextfile, put, putbinaryfile, and puttextfile use Kernel#open to open a local file. If the localfile argument starts with the “|” pipe character, the command following the pipe character is executed. The default value of localfile is File.basename(remotefile), so malicious FTP servers could cause arbitrary command execution.
www.securityfocus.com/bid/102204
www.securitytracker.com/id/1042004
access.redhat.com/errata/RHSA-2018:0378
access.redhat.com/errata/RHSA-2018:0583
access.redhat.com/errata/RHSA-2018:0584
access.redhat.com/errata/RHSA-2018:0585
access.redhat.com/errata/RHSA-2019:2806
lists.debian.org/debian-lts-announce/2017/12/msg00024.html
lists.debian.org/debian-lts-announce/2017/12/msg00025.html
lists.debian.org/debian-lts-announce/2018/07/msg00012.html
www.debian.org/security/2018/dsa-4259
www.exploit-db.com/exploits/43381/
www.ruby-lang.org/en/news/2017/12/14/net-ftp-command-injection-cve-2017-17405/
www.ruby-lang.org/en/news/2017/12/14/ruby-2-4-3-released/