The RubyGems maintainers determined that the reported symlink-following behavior during gem extraction is not a security vulnerability, so no vulnerability exists for this record to describe.

Denial of service when publishing a package on rubygems.org

Rubygems.org is the Ruby community's gem hosting service. A Gem publisher can cause a Remote DoS when publishing a Gem. This is due to how Ruby reads the Manifest of Gem files when using Gem::Specification.from_yaml. from_yaml makes use of SafeYAML.load which allows YAML aliases inside the YAML-based metadata of a gem. YAML aliases allow for Denial of Service attacks with so-called `YAML-bombs` (comparable to Billion laughs attacks). This was patched. There is is no action required by users. This issue is also tracked as GHSL-2024-001 and was discovered by the GitHub security lab.

Unauthorized gem takeover for some gems on rubygems.org

Rubygems is a package registry used to supply software for the Ruby language ecosystem. 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. To be vulnerable, a gem needed: one or more dashes in its name creation within 30 days OR no updates for over 100 days At present, we believe this vulnerability has not been exploited. RubyGems.org sends an email to all gem owners when a gem version is published or yanked. We have not received any support emails from gem owners indicating that their gem has been yanked 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. A deeper audit for any possible use of this exploit is ongoing, and we will update this advisory once it is complete. Using Bundler in --frozen or --deployment mode in CI and during deploys, as the Bundler team has always recommended, will guarantee that your application does not silently switch to versions created using this exploit. To audit your application history for possible past exploits, review your Gemfile.lock and look for gems whose platform changed when the version number did not change. For example, gemname-3.1.2 updating to gemname-3.1.2-java could indicate a possible abuse of this vulnerability. RubyGems.org has been patched and is no longer vulnerable to this issue as of the 5th of May 2022.

RubyGems allows creation of users with arbitrary unverified emails

RubyGems.org is the Ruby community gem host. A bug in password & email change confirmation code allowed an attacker to change their RubyGems.org account's email to an unowned email address. Having access to an account whose email has been changed could enable an attacker to save API keys for that account, and when a legitimate user attempts to create an account with their email (and has to reset password to gain access) and is granted access to other gems, the attacker would then be able to publish and yank versions of those gems. Commit number 90c9e6aac2d91518b479c51d48275c57de492d4d contains a patch for this issue.

Unauthorized takeover for new versions of some platform-specific gems

RubyGems is a package registry used to supply software for the Ruby language ecosystem. An ordering mistake in the code that accepts gem uploads allowed some gems (with platforms ending in numbers, like `arm64-darwin-21`) to be temporarily replaced in the CDN cache by a malicious package. The bug has been patched, and is believed to have never been exploited, based on an extensive review of logs and existing gems by rubygems. The easiest way to ensure that an application has not been exploited by this vulnerability is to verify all downloaded .gems checksums match the checksum recorded in the RubyGems.org database. RubyGems.org has been patched and is no longer vulnerable to this issue.

rubygems: Arbitrary file overwrite due to incorrect validation of specification name

RubyGems version 2.6.12 and earlier fails to validate specification names, allowing a maliciously crafted gem to potentially overwrite any file on the filesystem.

rubygems: Escape sequence in the "summary" field of gemspec

RubyGems version 2.6.12 and earlier is vulnerable to maliciously crafted gem specifications that include terminal escape characters. Printing the gem specification would execute terminal escape sequences.

rubygems: No size limit in summary length of gem spec

RubyGems version 2.6.12 and earlier is vulnerable to maliciously crafted gem specifications to cause a denial of service attack against RubyGems clients who have issued a `query` command.

rubygems: DNS hijacking vulnerability

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.

rubygems: Unsafe object deserialization through YAML formatted gem specifications

RubyGems versions between 2.0.0 and 2.6.13 are vulnerable to a possible remote code execution vulnerability. YAML deserialization of gem specifications can bypass class white lists. Specially crafted serialized objects can possibly be used to escalate to remote code execution.

rubygems: incomplete fix for CVE-2015-3900

RubyGems 2.0.x before 2.0.17, 2.2.x before 2.2.5, and 2.4.x before 2.4.8 does not validate the hostname when fetching gems or making API requests, which allows remote attackers to redirect requests to arbitrary domains via a crafted DNS SRV record with a domain that is suffixed with the original domain name, aka a "DNS hijack attack." NOTE: this vulnerability exists because to an incomplete fix for CVE-2015-3900.

rubygems: DNS hijacking vulnerability in api_endpoint()

RubyGems 2.0.x before 2.0.16, 2.2.x before 2.2.4, and 2.4.x before 2.4.7 does not validate the hostname when fetching gems or making API requests, which allows remote attackers to redirect requests to arbitrary domains via a crafted DNS SRV record, aka a "DNS hijack attack."

rubygems: Two security fixes in v1.8.23

RubyGems before 1.8.23 can redirect HTTPS connections to HTTP, which makes it easier for remote attackers to observe or modify a gem during installation via a man-in-the-middle attack.

rubygems: Two security fixes in v1.8.23

RubyGems before 1.8.23 does not verify an SSL certificate, which allows remote attackers to modify a gem during installation via a man-in-the-middle attack.

rubygems: version regex algorithmic complexity vulnerability

Algorithmic complexity vulnerability in Gem::Version::VERSION_PATTERN in lib/rubygems/version.rb in RubyGems before 1.8.23.1, 1.8.24 through 1.8.25, 2.0.x before 2.0.8, and 2.1.x before 2.1.0, as used in Ruby 1.9.0 through 2.0.0p247, allows remote attackers to cause a denial of service (CPU consumption) via a crafted gem version that triggers a large amount of backtracking in a regular expression.

rubygems: version regex algorithmic complexity vulnerability, incomplete CVE-2013-4287 fix

Algorithmic complexity vulnerability in Gem::Version::ANCHORED_VERSION_PATTERN in lib/rubygems/version.rb in RubyGems before 1.8.23.2, 1.8.24 through 1.8.26, 2.0.x before 2.0.10, and 2.1.x before 2.1.5, as used in Ruby 1.9.0 through 2.0.0p247, allows remote attackers to cause a denial of service (CPU consumption) via a crafted gem version that triggers a large amount of backtracking in a regular expression. NOTE: this issue is due to an incomplete fix for CVE-2013-4287.

rubygems.org MFA Bypass through password reset function could allow account takeover

Rubygems.org is the Ruby community's gem hosting service. Rubygems.org users with MFA enabled would normally be protected from account takeover in the case of email account takeover. However, a workaround on the forgotten password form allows an attacker to bypass the MFA requirement and takeover the account. This vulnerability has been patched in commit 0b3272a.

Unauthorized gem replacement for full names ending in numbers on rubygems.org

rubygems.org is the Ruby community's primary gem (library) hosting service. Insufficient input validation allowed malicious actors to replace any uploaded gem version that had a platform, version number, or gem name matching `/-\d/`, permanently replacing the legitimate upload in the canonical gem storage bucket, and triggering an immediate CDN purge so that the malicious gem would be served immediately. The maintainers have checked all gems matching the `/-\d/` pattern and can confirm that no unexpected `.gem`s were found. As a result, we believe this vulnerability was _not_ exploited. The easiest way to ensure that a user's applications were not exploited by this vulnerability is to check that all of your downloaded .gems have a checksum that matches the checksum recorded in the RubyGems.org database. RubyGems contributor Maciej Mensfeld wrote a tool to automatically check that all downloaded .gem files match the checksums recorded in the RubyGems.org database. You can use it by running: `bundle add bundler-integrity` followed by `bundle exec bundler-integrity`. Neither this tool nor anything else can prove you were not exploited, but the can assist your investigation by quickly comparing RubyGems API-provided checksums with the checksums of files on your disk. The issue has been patched with improved input validation and the changes are live. No action is required on the part of the user. Users are advised to validate their local gems.

rubygems: Escape sequence injection vulnerability in errors

An issue was discovered in RubyGems 2.6 and later through 3.0.2. Since Gem::CommandManager#run calls alert_error without escaping, escape sequence injection is possible. (There are many ways to cause an error.)

rubygems: Installing a malicious gem may lead to arbitrary code execution

An issue was discovered in RubyGems 2.6 and later through 3.0.2. A crafted gem with a multi-line name is not handled correctly. Therefore, an attacker could inject arbitrary code to the stub line of gemspec, which is eval-ed by code in ensure_loadable_spec during the preinstall check.