CVE-2022-36073 in RubyGems.org
Summary
by MITRE • 09/08/2022
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.
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Analysis
by VulDB Data Team • 10/14/2022
The vulnerability identified as CVE-2022-36073 represents a critical authorization flaw within RubyGems.org, the primary gem hosting platform for the ruby community. This security weakness stems from inadequate validation during the email address change confirmation process, creating a pathway for malicious actors to manipulate account ownership. The flaw specifically affects the confirmation code mechanism that should verify email ownership before allowing changes to account email addresses. When an attacker successfully exploits this vulnerability, they can redirect their account's email to an email address that does not yet exist in the system, effectively gaining unauthorized control over the account's associated privileges.
The technical implementation of this vulnerability lies in the insufficient verification logic that governs email address changes within the RubyGems.org platform. According to CWE-284, this represents an improper access control issue where the system fails to properly validate that the new email address is properly owned and verified before committing the change. The confirmation code mechanism, which should serve as a security barrier, contains a logical flaw that allows attackers to bypass the standard verification process. This weakness enables attackers to manipulate the email confirmation workflow and effectively take control of accounts through unauthorized email address changes.
The operational impact of this vulnerability extends far beyond simple account takeover, creating a multi-layered attack vector that can compromise the entire gem ecosystem. Once an attacker has successfully changed an account's email address, they can proceed to save API keys associated with that account, which provides them with elevated privileges within the RubyGems.org platform. When legitimate users attempt to create accounts using the compromised email addresses, they inadvertently gain access to other gems and associated administrative privileges. This creates a scenario where attackers can publish malicious versions of popular gems or yank legitimate versions, potentially causing widespread disruption across the ruby community. The attack chain follows ATT&CK technique T1078.004, which involves legitimate credentials gained through account manipulation, enabling persistent access to the platform's resources.
The security implications of this vulnerability are particularly severe due to the nature of gem distribution in the ruby ecosystem, where developers trust packages published by verified accounts. The patch referenced in commit 90c9e6aac2d91518b479c51d48275c57de492d4d addresses the core issue by implementing proper validation checks that ensure email addresses are verified before any account modifications are committed. This fix aligns with security best practices for maintaining account integrity and preventing unauthorized access to sensitive platform resources. The remediation process demonstrates the importance of proper input validation and confirmation mechanisms in preventing account takeover scenarios, particularly in environments where credential compromise can lead to supply chain attacks through package manipulation. Organizations maintaining similar platforms should implement similar validation controls to prevent analogous vulnerabilities in their systems.