CVE-2017-14849 in Node.js
Summary
by MITRE
Node.js 8.5.0 before 8.6.0 allows remote attackers to access unintended files, because a change to ".." handling was incompatible with the pathname validation used by unspecified community modules.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 11/20/2019
The vulnerability identified as CVE-2017-14849 represents a critical path traversal issue within Node.js version 8.5.0 that was subsequently addressed in version 8.6.0. This security flaw emerged from a modification in how the Node.js runtime handled ".." directory traversal sequences within file paths, creating an inconsistency between the core path validation mechanisms and those implemented by third-party community modules. The issue specifically affects the interaction between Node.js's internal file system operations and community-developed libraries that perform their own pathname validation, leading to potential unauthorized access to files outside the intended directory scope.
The technical root cause of this vulnerability lies in the incompatible handling of parent directory references within file paths. When Node.js processes file operations, it employs specific validation routines to prevent access to files outside designated directories. However, the update in version 8.5.0 introduced changes to how the ".." sequence was interpreted and validated, which conflicted with the validation approaches used by community modules. This incompatibility created a scenario where malicious actors could craft file paths that would bypass security checks implemented by these third-party libraries, potentially allowing access to sensitive files that should have been restricted.
The operational impact of CVE-2017-14849 extends beyond simple file access violations, as it represents a fundamental breakdown in the security model of Node.js applications. Attackers exploiting this vulnerability could potentially read files from locations outside the intended application scope, including system configuration files, database credentials, or other sensitive data. The vulnerability is particularly concerning because it affects community modules that are widely used in production environments, meaning that applications relying on these libraries could be compromised even if the core Node.js installation was updated. This creates a cascading security risk where a single update to the core framework may not be sufficient to protect against exploitation.
Security researchers have classified this vulnerability under the CWE-22 category, which specifically addresses path traversal attacks, and it aligns with ATT&CK technique T1083, which involves discovering files and directories. The vulnerability demonstrates how seemingly minor changes in core framework behavior can create significant security implications when interacting with community-developed components. Organizations using Node.js applications should prioritize updating to version 8.6.0 or later to address this vulnerability, while also reviewing their dependency management practices to ensure that community modules are compatible with the updated path validation mechanisms. Additionally, implementing proper input validation and access control measures at the application level can provide additional defense-in-depth protection against similar path traversal scenarios that may arise from other sources.