Critical Gems Takeover Bug Reported in RubyGems Package Manager

The maintainers of the RubyGems package manager have addressed a
critical security flaw that could have been abused to remove gems
and replace them with rogue versions under specific
circumstances.

“Due to a bug in the yank action, it was possible for any
RubyGems.org user to remove and replace certain gems even if that
user was not authorized to do so,” RubyGems said^[1]
in a security advisory published on May 6, 2022.

RubyGems, like npm for JavaScript and pip for Python, is a
package
manager^[2] and a gem hosting
service for the Ruby programming language, offering a repository of
more than 171,500 libraries.

In a nutshell, the flaw in question, tracked as CVE-2022-29176,
enabled anyone to pull certain gems and upload different files with
the same name, same version number, and different platforms.

For this to happen, however, a gem needed to have one or more
dashes in its name, where the word before the dash was the name of
an attacker-controlled gem, and which was created within 30 days or
had no updates for over 100 days.

“For example, the gem ‘something-provider’ could have been taken
over by the owner of the gem ‘something,'” the project owners
explained.

The project maintainers said that there is no evidence that the
vulnerability has been exploited in the wild, adding it didn’t
receive any support emails from gem owners alerting them to the
removal of the libraries without authorization.

“An audit of gem changes for the last 18 months did not find any
examples of this vulnerability being used in a malicious way,” the
maintainers said. “A deeper audit for any possible use of this
exploit is ongoing.”

The disclosure comes as NPM addressed several flaws in its
platform that could have been weaponized to facilitate account
takeover attacks and publish malicious packages.

Chief among them is a supply chain threat called package planting^[3]
that enables malicious actors to pass off rogue libraries as
legitimate simply by assigning them to trusted, popular maintainers
without their knowledge.