CVE-2017-7676 in Ranger
Summary
by MITRE
Policy resource matcher in Apache Ranger before 0.7.1 ignores characters after '*' wildcard character - like my*test, test*.txt. This can result in unintended behavior.
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Analysis
by VulDB Data Team • 12/28/2020
The vulnerability identified as CVE-2017-7676 resides within Apache Ranger's policy resource matcher component, which serves as a critical access control mechanism for managing permissions across various data resources. This flaw affects Apache Ranger versions prior to 0.7.1 and represents a significant security weakness in the system's authorization framework. The issue manifests when wildcard characters are used within resource patterns, specifically the asterisk symbol that should theoretically match any sequence of characters. The vulnerability stems from improper handling of wildcard matching logic where the system fails to correctly process patterns containing wildcard characters in the middle or at the end of resource names, creating potential bypass opportunities for unauthorized access.
The technical implementation flaw occurs in how Apache Ranger processes resource patterns containing the asterisk wildcard character. When users define resource policies using patterns such as mytest or test.txt, the system's resource matcher incorrectly interprets these patterns, leading to inconsistent matching behavior. This improper wildcard handling allows attackers to craft resource names that bypass intended access controls, as the system may match against partial patterns rather than complete resource specifications. The vulnerability specifically impacts the policy evaluation engine's ability to accurately determine whether a requested resource matches the defined policy patterns, creating a scenario where legitimate access controls are circumvented.
The operational impact of this vulnerability extends beyond simple access control bypasses, potentially enabling unauthorized data access and privilege escalation within systems protected by Apache Ranger. Attackers could exploit this weakness to gain access to resources that should be restricted based on their policy definitions, particularly in environments where fine-grained access control is essential for data protection. The vulnerability's implications are particularly severe in data governance scenarios where Ranger is used to enforce strict access controls over sensitive datasets, as it could allow unauthorized users to access restricted files, databases, or other resources that should be protected by specific policy rules. This weakness essentially undermines the integrity of the access control mechanism, creating potential data leakage and compliance violations.
Organizations using Apache Ranger should immediately implement mitigation strategies including upgrading to version 0.7.1 or later, which contains the patched resource matcher implementation. Security administrators should conduct thorough audits of existing Ranger policies to identify and remediate any resource patterns that might be susceptible to this wildcard matching issue. The mitigation approach should include reviewing all policy definitions that utilize wildcard characters, particularly those with patterns containing asterisks in the middle or at the end of resource names. Additionally, organizations should implement monitoring and logging mechanisms to detect anomalous access patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-254 in the Common Weakness Enumeration, which addresses "Security Features" and specifically targets weaknesses in access control mechanisms. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and initial access through weak access control implementations, potentially enabling adversaries to move laterally within systems where Ranger is deployed. The security community recognizes this as a critical access control bypass vulnerability that requires immediate attention to maintain the integrity of data protection frameworks.