RubyGems version 2.6.12 and earlier is vulnerable to a DNS hijacking vulnerability that allows a MITM attacker to force the RubyGems client to download and install gems from a server that the attacker controls.
The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Rubygems | Rubygems | * | 2.6.12 (including) |
| Red Hat Enterprise Linux 7 | RedHat | ruby-0:2.0.0.648-33.el7_4 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | RedHat | rh-ruby24-ruby-0:2.4.2-86.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | RedHat | rh-ruby22-ruby-0:2.2.9-19.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | RedHat | rh-ruby23-ruby-0:2.3.6-67.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS | RedHat | rh-ruby24-ruby-0:2.4.2-86.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS | RedHat | rh-ruby22-ruby-0:2.2.9-19.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS | RedHat | rh-ruby23-ruby-0:2.3.6-67.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-ruby24-ruby-0:2.4.2-86.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-ruby22-ruby-0:2.2.9-19.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-ruby23-ruby-0:2.3.6-67.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS | RedHat | rh-ruby24-ruby-0:2.4.2-86.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS | RedHat | rh-ruby22-ruby-0:2.2.9-19.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS | RedHat | rh-ruby23-ruby-0:2.3.6-67.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | rh-ruby24-ruby-0:2.4.2-86.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | rh-ruby22-ruby-0:2.2.9-19.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | rh-ruby23-ruby-0:2.3.6-67.el7 | * |
| Jruby | Ubuntu | artful | * |
| Jruby | Ubuntu | bionic | * |
| Jruby | Ubuntu | cosmic | * |
| Jruby | Ubuntu | disco | * |
| Jruby | Ubuntu | eoan | * |
| Jruby | Ubuntu | esm-apps/bionic | * |
| Jruby | Ubuntu | esm-apps/focal | * |
| Jruby | Ubuntu | esm-apps/xenial | * |
| Jruby | Ubuntu | focal | * |
| Jruby | Ubuntu | groovy | * |
| Jruby | Ubuntu | hirsute | * |
| Jruby | Ubuntu | impish | * |
| Jruby | Ubuntu | lunar | * |
| Jruby | Ubuntu | mantic | * |
| Jruby | Ubuntu | trusty | * |
| Jruby | Ubuntu | trusty/esm | * |
| Jruby | Ubuntu | xenial | * |
| Jruby | Ubuntu | zesty | * |
| Ruby2.0 | Ubuntu | trusty | * |
| Ruby2.3 | Ubuntu | artful | * |
| Ruby2.3 | Ubuntu | xenial | * |
| Ruby2.3 | Ubuntu | zesty | * |
Since DNS names can be easily spoofed or misreported, and it may be difficult for the product to detect if a trusted DNS server has been compromised, DNS names do not constitute a valid authentication mechanism. When the product performs a reverse DNS resolution for an IP address, if an attacker controls the DNS server for that IP address, then the attacker can cause the server to return an arbitrary hostname. As a result, the attacker may be able to bypass authentication, cause the wrong hostname to be recorded in log files to hide activities, or perform other attacks. Attackers can spoof DNS names by either (1) compromising a DNS server and modifying its records (sometimes called DNS cache poisoning), or (2) having legitimate control over a DNS server associated with their IP address.