CVE-2018-7164 in Node.js
Summary
by MITRE
Node.js versions 9.7.0 and later and 10.x are vulnerable and the severity is MEDIUM. A bug introduced in 9.7.0 increases the memory consumed when reading from the network into JavaScript using the net.Socket object directly as a stream. An attacker could use this cause a denial of service by sending tiny chunks of data in short succession. This vulnerability was restored by reverting to the prior behaviour.
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Analysis
by VulDB Data Team • 02/19/2020
The vulnerability identified as CVE-2018-7164 represents a memory consumption issue within Node.js runtime environments affecting versions 9.7.0 through 10.x. This flaw emerged from a specific code change introduced in version 9.7.0 that altered how network data is processed when utilizing net.Socket objects as streams. The technical implementation involves the internal handling of data buffering mechanisms that became inefficient when processing rapid successive data chunks over network connections. The vulnerability operates at the intersection of network I/O processing and memory management within the Node.js event loop architecture, creating a scenario where memory allocation patterns become suboptimal for certain data transmission patterns. This represents a classic example of a performance regression that manifests as a security concern due to its potential for resource exhaustion.
The operational impact of this vulnerability extends beyond simple performance degradation to actual denial of service conditions. Attackers can exploit this weakness by sending small data packets in rapid succession through network connections established via net.Socket objects, causing the application to consume excessive memory resources over time. The memory consumption increases progressively as the attacker continues sending these tiny chunks, eventually leading to system resource exhaustion that can cause applications to crash or become unresponsive. This attack vector is particularly concerning because it requires minimal resources from the attacker while potentially causing significant disruption to services, making it an attractive method for denial of service attacks against Node.js applications. The vulnerability was classified as medium severity due to the specific conditions required for exploitation, though the potential impact can be severe in production environments.
The underlying technical flaw stems from changes in how Node.js handles stream buffering and memory allocation when processing network data through net.Socket objects. The implementation introduced a regression where the memory management algorithms became less efficient when dealing with small, frequent data transfers, causing memory to be allocated in a manner that doesn't scale well with the volume of rapid data chunks. This behavior aligns with CWE-1321, which addresses memory allocation and deallocation issues in network applications, and demonstrates how seemingly minor code changes can introduce significant security implications. The vulnerability was addressed by reverting to the previous memory handling behavior, indicating that the fix required a return to established patterns rather than implementing a more sophisticated solution. The remediation process follows standard security practices for regression fixes, where the problematic code change is reversed to restore the previous stable state, though this approach may not address potential underlying architectural issues that could reappear in future modifications.
Organizations running Node.js applications should prioritize updating to versions that contain the fix for CVE-2018-7164, particularly those using versions 9.7.0 through 10.x where the vulnerability exists. The mitigation strategy involves not only applying the necessary version updates but also monitoring network traffic patterns for unusual memory consumption that might indicate exploitation attempts. Security teams should implement network monitoring solutions that can detect anomalous data transmission patterns and memory usage spikes that could indicate this specific vulnerability being targeted. Additionally, developers should review their application code to identify instances where net.Socket objects are used as streams and consider implementing additional safeguards or rate limiting mechanisms to prevent exploitation. The vulnerability demonstrates the importance of thorough regression testing when implementing network I/O improvements and highlights the need for security considerations in performance optimization efforts. This case study reinforces the ATT&CK framework concept of privilege escalation through resource exhaustion, where attackers leverage performance issues to achieve denial of service conditions that can impact system availability and service integrity.