CVE-2020-15012 in Nexus Repository Manager
Summary
by MITRE • 10/13/2020
A Directory Traversal issue was discovered in Sonatype Nexus Repository Manager 2.x before 2.14.19. A user that requests a crafted path can traverse up the file system to get access to content on disk (that the user running nxrm also has access to).
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Analysis
by VulDB Data Team • 11/18/2020
The vulnerability identified as CVE-2020-15012 represents a critical directory traversal flaw within Sonatype Nexus Repository Manager version 2.x prior to 2.14.19. This issue stems from inadequate input validation and path sanitization mechanisms that fail to properly restrict file system access when processing user-supplied paths. The flaw allows authenticated users to exploit malformed URI requests that contain directory traversal sequences such as ../ or ..\ to navigate outside the intended repository boundaries and access arbitrary files on the underlying file system. The vulnerability is classified under CWE-22 - Improper Limitation of a Pathname to a Restricted Directory and aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: PowerShell, as it enables unauthorized file access that could potentially lead to further exploitation. The affected system operates on a principle where the repository manager processes user requests without sufficient validation of the requested paths, creating a direct pathway for privilege escalation through file system traversal.
The technical implementation of this vulnerability occurs when the Nexus Repository Manager processes requests containing crafted paths that include directory traversal sequences. The application fails to properly sanitize or validate user inputs before using them in file system operations, allowing maliciously constructed paths to bypass normal access controls. When a user submits a request with a path containing traversal sequences, the system processes these paths without adequate restrictions, resulting in the application attempting to access files in parent directories of the intended repository location. This flaw specifically affects the file system access mechanisms within the repository manager, where the application does not enforce proper path validation or canonicalization before executing file operations. The vulnerability is particularly dangerous because it operates at the file system level, meaning that any file accessible to the user account running the Nexus process becomes potentially accessible to authenticated users of the repository manager. The issue exists in the core file handling logic of the application and is not limited to specific repository types or formats.
The operational impact of CVE-2020-15012 extends beyond simple unauthorized file access to potentially compromise the entire repository infrastructure and underlying system security. An attacker with access to the repository manager can traverse to sensitive files such as configuration files, credential stores, log files, or even system binaries that may contain sensitive information. This vulnerability could enable attackers to extract database connection strings, administrative credentials, or other sensitive configuration data that would otherwise be protected within the repository environment. The access granted through this vulnerability could facilitate further attacks including privilege escalation, data exfiltration, or even system compromise if the repository manager process has elevated privileges. The vulnerability affects the integrity and confidentiality of the repository environment, potentially exposing the entire organization's artifact storage to unauthorized access. Organizations using vulnerable versions of Nexus Repository Manager face significant risk of data breaches and regulatory compliance violations, particularly in environments where sensitive or proprietary software artifacts are stored.
Mitigation strategies for CVE-2020-15012 primarily focus on immediate remediation through version updates and implementation of additional security controls. The most effective solution is to upgrade to Nexus Repository Manager 2.14.19 or later versions where the directory traversal vulnerability has been patched. Organizations should also implement network segmentation and access controls to limit exposure of the repository manager to untrusted networks and users. Additional mitigations include implementing web application firewalls with path traversal detection capabilities, enforcing strict input validation at all application entry points, and regularly auditing file system permissions for the repository manager process. Security teams should conduct comprehensive vulnerability assessments to identify any potential exploitation attempts and implement monitoring solutions that can detect unusual file access patterns. The remediation process should also include reviewing and updating access control policies to ensure that only authorized personnel have access to the repository manager, and that access is granted based on the principle of least privilege. Organizations should also consider implementing file integrity monitoring solutions to detect unauthorized changes to critical repository files and configuration data.