CVE-2016-0735 in Ranger
Summary
by MITRE
Apache Ranger 0.5.x before 0.5.2 allows remote authenticated users to bypass intended parent resource-level access restrictions by leveraging mishandling of a resource-level exclude policy.
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Analysis
by VulDB Data Team • 10/03/2018
Apache Ranger represents a comprehensive security framework designed to provide centralized data security for Hadoop ecosystems, offering fine-grained access control and audit capabilities across various data storage and processing components. The vulnerability identified in CVE-2016-0735 specifically targets the access control mechanisms within Ranger version 0.5.x prior to 0.5.2, creating a significant security gap that could allow authenticated attackers to escalate their privileges and access resources they should not be permitted to reach. This flaw manifests in the improper handling of resource-level exclude policies, which are intended to define specific exclusions from broader access control rules, but instead create unexpected access pathways through the system's policy evaluation logic.
The technical flaw stems from how Ranger processes and evaluates resource-level policies when exclude conditions are present in the access control configuration. When administrators define exclude policies to restrict access to certain resources or resource hierarchies, the system fails to properly validate or enforce these restrictions during the access evaluation process. This misimplementation allows authenticated users to craft access requests that bypass the intended exclusion rules, effectively granting them access to parent resources or broader data sets that should be restricted based on the exclude policy configuration. The vulnerability operates at the policy evaluation layer, where the system's logic for determining access permissions becomes inconsistent when dealing with overlapping or conflicting policy rules, particularly those involving exclusion criteria.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it undermines the fundamental security model that Ranger is designed to enforce within Hadoop environments. Organizations relying on Ranger for data protection may find that their access control policies are being circumvented, potentially exposing sensitive data to unauthorized users who have legitimate authentication credentials but should be restricted from accessing specific resources. This issue particularly affects environments where administrators implement complex hierarchical access controls using parent-child resource relationships, as the bypass allows attackers to traverse these relationships in unintended ways. The vulnerability could lead to data breaches, compliance violations, and significant operational risks when sensitive datasets are accessed by unauthorized personnel, as the system's audit trails may not properly capture these unauthorized access attempts due to the policy bypass mechanism.
Organizations should immediately upgrade to Apache Ranger 0.5.2 or later versions to address this vulnerability, as the fix resolves the underlying policy evaluation logic that was allowing the bypass. Security teams should conduct thorough audits of existing Ranger configurations to identify any policies that might be susceptible to this bypass, particularly those involving complex resource hierarchies and exclusion rules. The vulnerability aligns with CWE-284, which addresses improper access control in software systems, and represents a specific implementation weakness in access control policy evaluation. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques where attackers leverage configuration flaws to gain access to restricted resources, potentially leading to data exfiltration and further system compromise. Organizations should also implement additional monitoring and logging controls to detect unusual access patterns that might indicate exploitation attempts, as the bypass may not always be immediately apparent in standard audit trails.