CVE-2015-7748 in Junos
Summary
by MITRE
Juniper chassis with Trio (Trinity) chipset line cards and Junos OS 13.3 before 13.3R8, 14.1 before 14.1R6, 14.2 before 14.2R5, and 15.1 before 15.1R2 allow remote attackers to cause a denial of service (MPC line card crash) via a crafted uBFD packet.
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Analysis
by VulDB Data Team • 06/22/2022
The vulnerability identified as CVE-2015-7748 affects Juniper Networks devices utilizing the Trio (Trinity) chipset architecture in their chassis-based networking equipment. This flaw specifically impacts Junos OS versions running on MPC (Multi-Processing Card) line cards where the Trio chipset is employed. The vulnerability resides in the processing of uBFD (unified Bidirectional Forwarding Detection) packets, which are critical components in network monitoring and failure detection protocols. The affected versions include specific releases of Junos OS 13.3, 14.1, 14.2, and 15.1, with the issue being resolved in the indicated patch releases. This vulnerability represents a significant concern for network infrastructure security as it allows remote attackers to exploit a weakness in the packet processing mechanism.
The technical flaw manifests when the system receives a crafted uBFD packet that triggers an improper memory handling condition within the Trio chipset's processing routines. This malformed packet causes the MPC line card to crash and restart, resulting in a denial of service condition that disrupts network connectivity and potentially impacts critical infrastructure operations. The vulnerability stems from insufficient input validation and memory management within the uBFD packet processing code, where the system fails to properly handle malformed packet structures that exceed expected parameters or contain unexpected data sequences. This type of vulnerability falls under CWE-129, which addresses insufficient input validation, and specifically relates to improper handling of input boundaries in network protocol processing. The attack vector is particularly concerning as it requires no authentication or local access, making it a remote code execution or denial of service vulnerability that can be exploited from outside the network perimeter.
The operational impact of CVE-2015-7748 extends beyond simple service disruption as it affects the reliability and availability of critical network infrastructure components. When MPC line cards crash due to this vulnerability, network traffic may be interrupted or rerouted through alternative paths, potentially causing performance degradation or complete connectivity loss in affected network segments. The vulnerability affects devices that rely heavily on BFD for rapid detection of forwarding path failures, which are fundamental to maintaining network stability and redundancy. Network administrators face the challenge of identifying affected devices and applying patches without disrupting ongoing operations, particularly in large-scale deployments where multiple chassis-based systems may be impacted. This vulnerability aligns with ATT&CK technique T1499.002, which describes network denial of service attacks, and represents a specific implementation weakness in network protocol handling that could be leveraged by adversaries to create persistent service disruption.
Mitigation strategies for CVE-2015-7748 require immediate patching of affected Junos OS versions with the vendor-released security updates. Organizations should prioritize updating their Trio chipset-based devices to the patched versions, specifically targeting releases 13.3R8, 14.1R6, 14.2R5, and 15.1R2. Network administrators should also implement network segmentation and monitoring to detect unusual packet patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation in network protocol implementations and highlights the need for comprehensive security testing of network infrastructure components. Organizations should conduct thorough inventory assessments to identify all affected devices and establish a coordinated patching schedule that minimizes operational impact while maintaining security posture. Additional defensive measures include implementing network access controls to limit exposure of vulnerable devices and monitoring for abnormal MPC line card behavior or frequent restart events that could indicate exploitation attempts.