Arch Linux Security Advisory ASA-202107-25 ========================================== Severity: High Date : 2021-07-14 CVE-ID : CVE-2021-31799 CVE-2021-31810 CVE-2021-32066 Package : ruby2.6 Type : multiple issues Remote : Yes Link : https://security.archlinux.org/AVG-2140 Summary ======= The package ruby2.6 before version 2.6.8-1 is vulnerable to multiple issues including silent downgrade, arbitrary command execution and information disclosure. Resolution ========== Upgrade to 2.6.8-1. # pacman -Syu "ruby2.6>=2.6.8-1" The problems have been fixed upstream in version 2.6.8. Workaround ========== None. Description =========== - CVE-2021-31799 (arbitrary command execution) RDoc before version 6.3.1, as bundled with Ruby before version 2.7.4 and 2.6.8 as well as GitLab before version 14.0.2, used to call Kernel#open to open a local file. If a Ruby project has a file whose name starts with "|" and ends with "tags", the command following the pipe character is executed. A malicious Ruby project could exploit it to run an arbitrary command execution against a user who attempts to run the rdoc command. - CVE-2021-31810 (information disclosure) A security issue has been discovered in Ruby before versions 3.0.2, 2.7.4 and 2.6.8. A malicious FTP server can use the PASV response to trick Net::FTP into connecting back to a given IP address and port. This potentially makes Net::FTP extract information about services that are otherwise private and not disclosed (e.g., the attacker can conduct port scans and service banner extractions). - CVE-2021-32066 (silent downgrade) A security issue has been discovered in Ruby before versions 3.0.2, 2.7.4 and 2.6.8. Net::IMAP does not raise an exception when StartTLS fails with an unknown response, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a “StartTLS stripping attack”. Impact ====== A remote man-in-the-middle attacker could strip StartTLS encryption from IMAP connections to disclose authentication credentials and emails. Furthermore, a malicious FTP server could induce connections to an arbitrary IP address and port on a client, leading to potential information disclosure. References ========== https://www.ruby-lang.org/en/news/2021/05/02/os-command-injection-in-rdoc/ https://github.com/ruby/rdoc/commit/a7f5d6ab88632b3b482fe10611382ff73d14eed7 https://github.com/ruby/ruby/commit/483f303d02e768b69e476e0b9be4ab2f26389522 https://github.com/ruby/ruby/commit/fe3c49c9baeeab58304ede915b7edd18ecf360fc https://www.ruby-lang.org/en/news/2021/07/07/trusting-pasv-responses-in-net-... https://hackerone.com/reports/1145454 https://github.com/ruby/net-ftp/commit/5709ece67cf57a94655e34532f8a7899b28d4... https://www.ruby-lang.org/en/news/2021/07/07/starttls-stripping-in-net-imap/ https://hackerone.com/reports/1178562 https://github.com/ruby/net-imap/commit/adba6f0c3e5c5607c4822b9120322eb7e9a7... https://security.archlinux.org/CVE-2021-31799 https://security.archlinux.org/CVE-2021-31810 https://security.archlinux.org/CVE-2021-32066