Access Bypass Vulnerabilities Patched in Drupal 8

A Drupal 8 security update released on Wednesday addresses several access bypass vulnerabilities affecting components such as views, the REST API and the entity access system.

The most severe of the flaws patched by Drupal 8.3.7 is CVE-2017-6925, a critical issue affecting the entity access system. The weakness can be exploited to view, create, delete or update entities. According to Drupal developers, only entities that don’t have UUIDs and ones that have different access restrictions on different revisions of the same entity are impacted.

Another access bypass vulnerability patched in the latest version of Drupal is CVE-2017-6924, which involves the REST API being able to bypass comment approval.

“When using the REST API, users without the correct permission can post comments via REST that are approved even if the user does not have permission to post approved comments,” Drupal said in its advisory.

This issue has been classified as moderately critical as only sites that have the RESTful Web Services module and the comment entity REST resource enabled are affected. Furthermore, the attacker needs access to a user account that is allowed to post comments, or the targeted website needs to allow comments from anonymous users.

Another moderately critical flaw is CVE-2017-6923, which affects the “views” component. While this vulnerability does not affect the Drupal 7 core, it does impact the Drupal 7 Views module, for which an update has been made available.

“When creating a view, you can optionally use Ajax to update the displayed data via filter parameters. The views subsystem/module did not restrict access to the Ajax endpoint to only views configured to use Ajax. This is mitigated if you have access restrictions on the view,” Drupal said. “It is best practice to always include some form of access restrictions on all views, even if you are using another module to display them.”

Earlier this summer, Drupal updated versions 7 and 8 to address a vulnerability that had been exploited in spam campaigns since October 2016. The developers of the open source content management system (CMS) initially advised users to ensure that their websites are properly configured and later introduced a protection designed to prevent exploitation.

Related: Flaw in Drupal Module Exposes 120,000 Sites to Attacks

Related: Drupal Patches Critical Access Bypass Flaw

Related: Several Vulnerabilities Patched in Drupal 8

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Eduard Kovacs is an international correspondent for SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

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