CVE-2015-3187 in Subversion
Summary
by MITRE
The svn_repos_trace_node_locations function in Apache Subversion before 1.7.21 and 1.8.x before 1.8.14, when path-based authorization is used, allows remote authenticated users to obtain sensitive path information by reading the history of a node that has been moved from a hidden path.
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Analysis
by VulDB Data Team • 06/07/2022
The vulnerability identified as CVE-2015-3187 affects Apache Subversion versions prior to 1.7.21 and 1.8.x versions before 1.8.14, representing a significant information disclosure flaw within the version control system's authorization mechanisms. This vulnerability specifically targets the svn_repos_trace_node_locations function which handles path-based authorization in Subversion repositories. The flaw enables remote authenticated attackers to bypass access controls and retrieve sensitive path information through a sophisticated technique involving node history traversal. The vulnerability stems from insufficient validation of node location history when path-based authorization is enabled, creating a pathway for unauthorized information disclosure.
The technical exploitation of this vulnerability relies on the manipulation of node history tracking within Subversion's repository structure. When a node is moved from a hidden path to a visible location, the svn_repos_trace_node_locations function fails to properly validate the authorization status of the original path during history tracing. This creates a scenario where authenticated users can access node location information that should remain restricted due to path-based authorization policies. The flaw operates at the repository level where Subversion maintains historical records of node movements, allowing attackers to reconstruct access paths that would normally be hidden from their permissions scope. This represents a classic case of insufficient authorization checking during historical data access operations.
The operational impact of CVE-2015-3187 extends beyond simple information disclosure, as it undermines the fundamental security model of path-based authorization within Subversion repositories. Attackers can potentially map out entire repository structures, identify sensitive directories, and discover access patterns that reveal organizational information architecture. The vulnerability affects organizations that rely on Subversion for source code management and where path-based access controls are implemented to restrict access to specific directories or branches. This could lead to exposure of proprietary code, development paths, or sensitive project information that should remain confidential within the organization's access control framework. The impact is particularly severe in environments where Subversion serves as a critical component of software development infrastructure and where unauthorized access to repository structure information could facilitate further attacks.
Security mitigations for CVE-2015-3187 require immediate patching of affected Subversion installations to versions 1.7.21 or 1.8.14 and later. Organizations should also implement comprehensive access control reviews to ensure that path-based authorization policies are properly configured and monitored. The vulnerability aligns with CWE-200, which addresses improper exposure of sensitive information, and relates to ATT&CK technique T1083, which covers directory and file system discovery. Additionally, this vulnerability demonstrates characteristics of privilege escalation through information gathering, potentially enabling attackers to map repository structures before attempting more targeted attacks. Organizations should consider implementing additional monitoring for unusual access patterns and node history queries that could indicate exploitation attempts. The fix implemented by Apache Subversion addresses the core authorization validation issue in the svn_repos_trace_node_locations function, ensuring that historical node location access respects current authorization policies rather than allowing access based on historical path information.