CVE-2016-3698 in NetworkManager
Summary
by MITRE
libndp before 1.6, as used in NetworkManager, does not properly validate the origin of Neighbor Discovery Protocol (NDP) messages, which allows remote attackers to conduct man-in-the-middle attacks or cause a denial of service (network connectivity disruption) by advertising a node as a router from a non-local network.
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Analysis
by VulDB Data Team • 10/06/2024
The vulnerability described in CVE-2016-3698 represents a critical flaw in the libndp library version 1.5 and earlier, which is utilized by NetworkManager for handling Neighbor Discovery Protocol messages in IPv6 networks. This issue stems from inadequate validation mechanisms that fail to properly verify the source of NDP advertisements, creating a significant security gap in network infrastructure. The flaw specifically affects systems that rely on libndp for managing IPv6 neighbor discovery processes, particularly in environments where NetworkManager is deployed to handle network configuration and connectivity management.
The technical implementation of this vulnerability occurs at the network protocol level where the libndp library processes incoming NDP messages without sufficient validation of the message origin. When a remote attacker sends forged NDP advertisements claiming to be a router from a non-local network, the vulnerable library accepts these messages without proper authentication or source verification. This allows attackers to manipulate the network routing table and redirect traffic through malicious nodes. The flaw operates at the link-layer protocol level where NDP messages are typically expected to originate from local network devices, but the library fails to enforce this constraint, enabling attackers to inject false routing information.
From an operational impact perspective, this vulnerability creates multiple attack vectors that can severely disrupt network connectivity and enable sophisticated man-in-the-middle attacks. Attackers can leverage this flaw to redirect network traffic through their compromised nodes, potentially intercepting sensitive data or disrupting communication between network endpoints. The denial of service aspect of this vulnerability can cause complete network connectivity disruption when legitimate router advertisements are replaced with malicious ones, leading to network partitions and service outages. This vulnerability affects systems that rely on IPv6 connectivity and are configured to automatically accept router advertisements, which is common in modern network environments.
The security implications of CVE-2016-3698 align with CWE-20, which describes improper input validation, and can be categorized under ATT&CK technique T1566 for initial access through spearphishing attachments or links. This vulnerability demonstrates the importance of validating network protocol messages at multiple layers of the network stack, particularly in systems that handle routing information. Organizations using NetworkManager or systems that depend on libndp for IPv6 management are at risk, especially in environments where network security is not properly segmented or where administrative access controls are insufficient. The vulnerability represents a classic case of insufficient validation that allows privilege escalation through network protocol manipulation.
Mitigation strategies for this vulnerability include upgrading to libndp version 1.6 or later, which contains proper validation mechanisms for NDP message origins. Network administrators should also implement additional security controls such as enabling router advertisement filtering, configuring NetworkManager to ignore router advertisements from non-local sources, and deploying network segmentation controls. The fix addresses the root cause by implementing proper source validation checks that verify the network scope of incoming NDP messages and ensure they originate from appropriate network segments. Organizations should also consider implementing network monitoring solutions that can detect anomalous NDP behavior and alert administrators to potential attacks. This vulnerability highlights the critical need for robust input validation in network protocol implementations and demonstrates how seemingly minor validation flaws can lead to significant security implications in network infrastructure components.