CVE-2024-27090 in Decidim
Summary
by MITRE • 07/10/2024
Decidim is a participatory democracy framework, written in Ruby on Rails, originally developed for the Barcelona City government online and offline participation website. If an attacker can infer the slug or URL of an unpublished or private resource, and this resource can be embbeded (such as a Participatory Process, an Assembly, a Proposal, a Result, etc), then some data of this resource could be accessed. This vulnerability is fixed in 0.27.6.
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Analysis
by VulDB Data Team • 07/11/2024
The vulnerability described in CVE-2024-27090 affects Decidim, a participatory democracy framework built on Ruby on Rails that serves as the foundation for citizen engagement platforms including the Barcelona City government's online participation website. This security flaw represents a significant information disclosure issue that undermines the privacy controls designed to protect unpublished or private content within the platform. The vulnerability specifically targets the access control mechanisms that should prevent unauthorized users from viewing sensitive data associated with various participatory democracy resources including processes, assemblies, proposals, and results.
The technical implementation of this vulnerability stems from insufficient access controls within the application's URL routing and resource handling logic. When resources are marked as unpublished or private, the system should enforce strict access restrictions that prevent unauthorized users from accessing these materials through direct URL manipulation. However, the flaw allows attackers to exploit predictable slugs or URLs to gain unauthorized access to embedded resources that should remain hidden from public view. This represents a classic case of inadequate input validation and access control enforcement, where the system fails to properly verify user permissions before serving content. The vulnerability manifests when attackers can infer or guess the URL structure of private resources and subsequently access embedded data that should be restricted to authorized users only.
The operational impact of this vulnerability extends beyond simple data exposure to potentially compromise the integrity of participatory democracy processes. When unauthorized individuals can access unpublished proposals, assembly discussions, or process results, it undermines the trust and security that participants expect in these democratic platforms. The affected resources could contain sensitive information about citizen opinions, policy discussions, or strategic planning that should remain confidential until appropriate publication times. This exposure could lead to manipulation of public discourse, unauthorized influence on decision-making processes, or potential harassment of participants who shared private information within these platforms. The vulnerability particularly affects the core functionality of Decidim's participatory democracy framework, as it directly undermines the fundamental principle that private or unpublished content should remain inaccessible to unauthorized users.
Security mitigations for this vulnerability should focus on implementing robust access control mechanisms that enforce proper authorization checks at multiple levels within the application. The fix implemented in version 0.27.6 likely includes enhanced URL validation, stricter permission checks for resource access, and improved handling of embedded content that prevents unauthorized access based on resource status. Organizations using Decidim should immediately upgrade to version 0.27.6 or later to address this vulnerability. Additional protective measures include implementing comprehensive logging of access attempts to private resources, conducting regular security audits of URL routing logic, and ensuring that all embedded content properly enforces access controls. This vulnerability aligns with CWE-284 Access Control Issues, specifically addressing improper access control mechanisms that allow unauthorized access to protected resources. The attack pattern corresponds to techniques described in MITRE ATT&CK framework under T1213 Data from Information Repositories, where adversaries seek unauthorized access to sensitive data within information systems. Organizations should also consider implementing web application firewalls and access control policies that monitor for suspicious URL patterns and unauthorized access attempts to private resources.