CVE-2018-15464 in ASR 900
Summary
by MITRE
A vulnerability in Cisco 900 Series Aggregation Services Router (ASR) software could allow an unauthenticated, remote attacker to cause a partial denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient handling of certain broadcast packets ingress to the device. An attacker could exploit this vulnerability by sending large streams of broadcast packets to an affected device. If successful, an exploit could allow an attacker to impact services running on the device, resulting in a partial DoS condition.
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Analysis
by VulDB Data Team • 06/26/2023
The vulnerability identified as CVE-2018-15464 affects Cisco 900 Series Aggregation Services Routers (ASR) and represents a significant security flaw in network infrastructure equipment. This issue resides within the software implementation of these routers, specifically in their handling of incoming broadcast traffic. The vulnerability is classified as a remote attack vector that does not require authentication, making it particularly dangerous as any external attacker can potentially exploit it without needing valid credentials or network access. The affected devices operate as critical network components that typically handle substantial traffic loads and serve as aggregation points for multiple network segments.
The technical root cause of this vulnerability stems from inadequate processing mechanisms for broadcast packets entering the affected Cisco ASR devices. When these routers receive large streams of broadcast packets, their software fails to properly manage the ingress traffic, leading to resource exhaustion or operational instability. This insufficient handling creates a condition where the device's normal operations become disrupted, resulting in partial denial of service. The flaw specifically manifests during the packet processing phase, where the router's ingress filtering and traffic management systems cannot adequately cope with the volume or characteristics of malicious broadcast traffic. This weakness aligns with common software design patterns that fail to implement proper input validation and resource allocation controls for network traffic processing.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise network reliability and availability. When exploited successfully, the vulnerability can cause partial denial of service conditions that may affect routing services, network connectivity, and overall device performance. Network administrators may observe degraded performance, intermittent connectivity issues, or selective service failures on affected routers. The partial nature of the DoS condition suggests that while complete device failure might not occur, critical network functions could be impaired, potentially affecting business operations and network infrastructure reliability. This vulnerability particularly impacts organizations that rely heavily on Cisco ASR 900 Series routers for their network backbone infrastructure, as these devices often serve as critical aggregation points for enterprise or service provider networks.
Mitigation strategies for this vulnerability should focus on implementing network-level protections and firmware updates. Cisco has released patches and software updates to address this specific flaw, and organizations should prioritize applying these updates to affected devices. Network administrators can also implement traffic filtering mechanisms to limit broadcast packet ingress, particularly from untrusted sources. The implementation of ingress filtering and rate limiting on affected routers can help reduce the impact of potential attacks by controlling the volume of broadcast traffic entering the device. Additionally, monitoring network traffic for unusual patterns of broadcast activity can provide early detection of potential exploitation attempts. This vulnerability demonstrates the importance of proper input validation and resource management in network infrastructure software, aligning with CWE categories related to insufficient input validation and resource exhaustion. From an ATT&CK framework perspective, this vulnerability maps to techniques involving denial of service and network infrastructure manipulation, emphasizing the need for robust network device security controls and regular vulnerability management processes.