CVE-2019-0056 in Junos
Summary
by MITRE
This issue only affects devices with three (3) or more MPC10's installed in a single chassis with OSPF enabled and configured on the device. An Insufficient Resource Pool weakness allows an attacker to cause the device's Open Shortest Path First (OSPF) states to transition to Down, resulting in a Denial of Service (DoS) attack. This attack requires a relatively large number of specific Internet Mixed (IMIXed) types of genuine and valid IPv6 packets to be transferred by the attacker in a relatively short period of time, across three or more PFE's on the device at the same time. Continued receipt of the traffic sent by the attacker will continue to cause OSPF to remain in the Down starting state, or flap between other states and then again to Down, causing a persistent Denial of Service. This attack will affect all IPv4, and IPv6 traffic served by the OSPF routes once the OSPF states transition to Down. This issue affects: Juniper Networks Junos OS on MX480, MX960, MX2008, MX2010, MX2020: 18.1 versions prior to 18.1R2-S4, 18.1R3-S5; 18.1X75 version 18.1X75-D10 and later versions; 18.2 versions prior to 18.2R1-S5, 18.2R2-S3, 18.2R3; 18.2X75 versions prior to 18.2X75-D50; 18.3 versions prior to 18.3R1-S4, 18.3R2, 18.3R3; 18.4 versions prior to 18.4R1-S2, 18.4R2.
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Analysis
by VulDB Data Team • 01/05/2024
This vulnerability represents a sophisticated denial of service weakness affecting juniper networks mx series routers with specific hardware and software configurations. The issue manifests when devices contain three or more mpc10 line cards installed in a single chassis while operating with ospf protocol enabled and configured. The root cause lies in an insufficient resource pool allocation that becomes overwhelmed during specific network traffic patterns, leading to ospf state transitions to down. This represents a classic resource exhaustion attack vector where legitimate network operations are disrupted through careful manipulation of protocol states rather than simple traffic flooding.
The attack requires a specific and substantial traffic pattern involving imixed types of genuine and valid ipv6 packets transmitted across multiple packet forwarding engines simultaneously. This requirement demonstrates the attack's sophistication and the need for precise coordination across multiple hardware components within the same chassis. The attacker must maintain sustained traffic flow across three or more pfe's to maintain the persistent denial of service condition, indicating the vulnerability's dependence on multi-path traffic manipulation rather than single point attacks.
The operational impact of this vulnerability extends beyond simple service disruption to encompass complete routing protocol failure across both ipv4 and ipv6 traffic streams. Once ospf states transition to down, all routing information becomes stale and traffic destined through ospf routes fails completely. This creates cascading effects throughout the network infrastructure as routing decisions become impossible, effectively cutting off communication paths that depend on the affected ospf configurations. The persistent nature of the attack means that once initiated, the service disruption continues until manual intervention or system reboot occurs.
This vulnerability aligns with cwe-400 resource exhaustion weakness classification and maps to attack techniques involving protocol manipulation and state machine exploitation. The attack pattern follows established methods for disrupting routing protocols through resource exhaustion, similar to other ospf-based attacks documented in cybersecurity literature. The specific requirement for multiple pfe's and imixed packet types indicates this vulnerability exploits design limitations in how the juniper operating system handles concurrent routing protocol states across multiple hardware components. Network administrators must understand that this attack does not require malicious packet content but rather specific timing and volume patterns that overwhelm internal resource pools.
Mitigation strategies should focus on implementing proper traffic rate limiting and monitoring for unusual packet patterns across multiple pfe's simultaneously. The most effective immediate solution involves upgrading to patched versions of junos os as specified in the advisory, which addresses the underlying resource pool allocation issues. Additionally, network segmentation and ospf configuration changes can reduce attack surface by limiting the number of mpc10 cards or disabling ospf on non-critical paths. The vulnerability demonstrates the importance of understanding how hardware configurations interact with software protocol implementations, particularly in high-end networking equipment where complex multi-chassis architectures create unique attack vectors.