CVE-2010-3093 in Drupal
Summary
by MITRE
The comment module in Drupal 5.x before 5.23 and 6.x before 6.18 allows remote authenticated users with certain privileges to bypass intended access restrictions and reinstate removed comments via a crafted URL, related to an "unpublishing bypass" issue.
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Analysis
by VulDB Data Team • 09/25/2021
The vulnerability identified as CVE-2010-3093 represents a critical access control flaw within Drupal's comment module that affects versions prior to 5.23 and 6.18. This issue stems from a design flaw in how the system handles comment status transitions, specifically when comments are unpublished and subsequently re-published. The vulnerability allows authenticated users who possess certain privileges to manipulate URL parameters and effectively bypass the intended access controls that should prevent them from viewing or interacting with comments they should not have access to. The flaw operates through a path traversal mechanism where the system fails to properly validate the state of comments during the unpublishing process, creating a window where previously removed content can be reinstated without proper authorization. This type of vulnerability falls under CWE-284 which specifically addresses improper access control mechanisms, and it aligns with ATT&CK technique T1078 which covers valid accounts and credential access through privilege escalation.
The technical implementation of this vulnerability exploits a weakness in the comment module's URL handling logic where the system does not properly validate whether a user has the necessary permissions to access a comment that has been removed or unpublished. When an administrator removes a comment, the system should ensure that the comment cannot be accessed through direct URL manipulation or by exploiting the unpublishing process. However, the flaw allows authenticated users to craft specific URLs that bypass these security checks, effectively reinstating access to comments that should have been completely removed from public view. The vulnerability is particularly dangerous because it operates within the existing authentication framework rather than requiring additional credentials, making it easier to exploit in real-world scenarios.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to access sensitive information that was intended to be removed from the system. This includes potentially confidential discussions, private communications, or content that was deliberately unpublished for security or privacy reasons. The vulnerability creates a persistent backdoor that remains active until the system is patched, allowing attackers to repeatedly access removed content without detection. Organizations using vulnerable Drupal installations face significant risks including data leakage, compliance violations, and potential reputational damage when sensitive information is exposed through this bypass mechanism. The vulnerability also undermines the integrity of the content management system's access control policies, potentially leading to cascading security issues within the broader application framework.
Mitigation strategies for CVE-2010-3093 require immediate patching of affected Drupal installations to versions 5.23 or 6.18 where the vulnerability has been addressed through proper input validation and access control enforcement. Organizations should also implement network segmentation to limit access to administrative functions, regularly audit comment access logs to detect potential exploitation attempts, and consider implementing additional monitoring for unusual URL patterns that might indicate exploitation of this vulnerability. The fix implemented in the patched versions ensures that the comment module properly validates user permissions during all comment state transitions, preventing unauthorized access to content that has been removed or unpublished. Security teams should also conduct comprehensive vulnerability assessments to identify any other potential access control bypasses within their Drupal installations and implement proper security monitoring to detect similar issues in other components of their web applications.