CVE-2021-29435 in trestle-auth
Summary
by MITRE • 04/14/2021
trestle-auth is an authentication plugin for the Trestle admin framework. A vulnerability in trestle-auth versions 0.4.0 and 0.4.1 allows an attacker to create a form that will bypass Rails' built-in CSRF protection when submitted by a victim with a trestle-auth admin session. This potentially allows an attacker to alter protected data, including admin account credentials. The vulnerability has been fixed in trestle-auth 0.4.2 released to RubyGems.
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Analysis
by VulDB Data Team • 04/17/2021
The vulnerability identified as CVE-2021-29435 affects trestle-auth, an authentication plugin designed for the Trestle admin framework that provides administrative interfaces for web applications. This authentication component serves as a critical security control within the framework, managing user sessions and access permissions for administrative functions. The flaw exists specifically in versions 0.4.0 and 0.4.1 of the plugin, creating a significant security weakness that could be exploited by malicious actors to compromise administrative access and data integrity.
The technical flaw stems from a failure in the plugin's implementation of Rails' built-in Cross-Site Request Forgery (CSRF) protection mechanisms. CSRF protection is a fundamental web security feature designed to prevent unauthorized commands from being executed on behalf of authenticated users. When an attacker crafts a malicious form that bypasses this protection, they can exploit the vulnerability to submit requests that appear to originate from a legitimate authenticated session. This occurs because the plugin does not properly validate or enforce CSRF tokens for certain administrative operations, allowing crafted requests to be processed without proper authentication verification.
The operational impact of this vulnerability is substantial as it enables attackers to manipulate protected administrative data without requiring valid credentials for the target account. The most serious consequence involves the potential modification of admin account credentials, which could lead to complete compromise of administrative access to the application. Additionally, attackers could potentially alter other protected data within the Trestle admin framework, including user accounts, configuration settings, or content management elements. This vulnerability essentially allows privilege escalation from a regular user to an administrator level, creating a severe security risk for applications relying on this authentication plugin.
The vulnerability has been addressed through the release of trestle-auth version 0.4.2, which properly implements CSRF protection mechanisms and validates requests according to Rails security standards. Organizations using affected versions should immediately upgrade to the patched version to mitigate the risk. Security practitioners should also conduct thorough assessments of their Trestle admin frameworks to identify any potential exploitation attempts and ensure proper security configurations are in place. This vulnerability aligns with CWE-352, which specifically addresses Cross-Site Request Forgery, and represents a typical example of how authentication plugins can introduce security weaknesses when not properly implementing standard web security controls.
From a threat modeling perspective, this vulnerability demonstrates the importance of proper security controls in authentication systems and the potential for seemingly minor implementation flaws to create significant security risks. The attack vector relies on social engineering or session hijacking techniques to deliver malicious forms to victims, making it particularly dangerous in environments where users may encounter untrusted content. Security teams should implement monitoring for suspicious administrative activities and ensure that all authentication components properly enforce CSRF protections as specified in OWASP security guidelines and the NIST Cybersecurity Framework. The fix in version 0.4.2 represents a standard remediation approach that restores proper token validation and session management controls necessary to prevent unauthorized administrative actions.