CVE-2018-0418 in ASR 9000
Summary
by MITRE
A vulnerability in the Local Packet Transport Services (LPTS) feature set of Cisco ASR 9000 Series Aggregation Services Router Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a lack of input and validation checking on certain Precision Time Protocol (PTP) ingress traffic to an affected device. An attacker could exploit this vulnerability by injecting malformed traffic into an affected device. A successful exploit could allow the attacker to cause services on the device to become unresponsive, resulting in a DoS condition. Cisco Bug IDs: CSCvj22858.
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Analysis
by VulDB Data Team • 05/02/2023
The vulnerability identified as CVE-2018-0418 affects Cisco ASR 9000 Series Aggregation Services Routers and resides within the Local Packet Transport Services feature set. This particular weakness stems from insufficient validation mechanisms applied to Precision Time Protocol (PTP) traffic entering the device through ingress points. The flaw represents a critical security gap in the router's traffic processing pipeline where incoming PTP packets are not properly sanitized or validated before being processed by the system's core services.
The technical implementation of this vulnerability demonstrates a classic input validation failure that aligns with CWE-20, which encompasses weaknesses related to improper input validation. Attackers can exploit this condition by crafting and injecting malformed PTP traffic directly into the network path of an affected router. The absence of proper validation checks means that malformed packets can traverse the normal processing flow and potentially trigger unexpected behavior within the router's operational systems. This type of attack vector falls under the ATT&CK technique T1498, specifically targeting network denial of service conditions through manipulation of network services.
The operational impact of this vulnerability extends beyond simple service disruption, as it can render critical network infrastructure completely unresponsive to legitimate traffic. When exploited successfully, the malformed PTP traffic can cause the router's services to become unresponsive, leading to complete denial of service conditions that can affect entire network segments depending on the router's role in the infrastructure. This vulnerability particularly affects network availability and reliability, as the affected device may require manual intervention or reboot to restore normal operations, potentially causing cascading failures in larger network deployments where multiple routers depend on synchronized timing protocols.
Mitigation strategies for CVE-2018-0418 should prioritize immediate implementation of network access control measures to restrict ingress PTP traffic to trusted sources only. Network administrators should consider implementing ingress filtering mechanisms that validate packet headers and content before allowing PTP traffic to reach the router's processing engines. The vulnerability also underscores the importance of regular firmware updates and security patches as recommended by Cisco's security advisories. Additionally, implementing monitoring solutions that can detect anomalous PTP traffic patterns may help identify exploitation attempts before they cause significant service disruption, while network segmentation strategies can limit the potential impact of successful attacks on critical infrastructure components.