CVE-2014-3270 in IOS XR
Summary
by MITRE
The DHCPv6 implementation in Cisco IOS XR allows remote attackers to cause a denial of service (process hang) via a malformed packet, aka Bug ID CSCul80924.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 06/20/2021
The vulnerability identified as CVE-2014-3270 represents a critical denial of service weakness within Cisco IOS XR operating systems that specifically affects the Dynamic Host Configuration Protocol version 6 implementation. This flaw exists in the network operating system's handling of DHCPv6 packets, creating a scenario where malicious actors can exploit malformed network traffic to disrupt normal service operations. The vulnerability was catalogued under Cisco Bug ID CSCul80924, indicating its classification within the vendor's internal tracking system for security issues. The DHCPv6 protocol serves as a critical component in IPv6 network environments, enabling automated assignment of IP addresses and network configuration parameters to devices, making this vulnerability particularly concerning for network infrastructure operators.
The technical root cause of this vulnerability stems from insufficient input validation within the DHCPv6 processing code of Cisco IOS XR. When the system receives a malformed DHCPv6 packet containing malformed options or incorrect packet structures, the parsing routine fails to properly handle these anomalies, resulting in a process hang condition. This occurs because the software lacks proper error handling mechanisms to gracefully manage malformed data inputs, causing the affected process to become unresponsive and consume system resources without recovery. The vulnerability demonstrates a classic example of inadequate bounds checking and input sanitization, where the system does not adequately validate packet contents before attempting to process them, leading to a denial of service condition that can persist until manual intervention or system restart occurs.
The operational impact of this vulnerability extends beyond simple service disruption, potentially affecting entire network segments that rely on DHCPv6 for IPv6 address allocation and configuration management. Network administrators may experience complete loss of DHCPv6 functionality, preventing new devices from joining the IPv6 network or causing existing devices to lose connectivity. This vulnerability particularly affects service providers and enterprise networks that have deployed Cisco IOS XR routers as core infrastructure components, as these devices often serve as critical network gateways and routing points. The remote nature of the attack vector means that adversaries can exploit this weakness from outside the network perimeter, requiring minimal privileges and technical expertise to execute successful attacks. According to the ATT&CK framework, this vulnerability aligns with the technique of "Network Denial of Service" under the T1498 category, representing a method for disrupting network services through malformed packet injection.
Mitigation strategies for CVE-2014-3270 should prioritize immediate implementation of Cisco's official security patches and software updates that address the input validation flaws in the DHCPv6 processing code. Network administrators should implement access control measures to restrict DHCPv6 traffic to trusted sources only, utilizing firewall rules and access control lists to limit exposure. The deployment of network monitoring solutions capable of detecting malformed DHCPv6 packets can provide early warning of potential exploitation attempts. Additionally, implementing redundant network paths and failover mechanisms can help maintain service availability during exploitation attempts. Organizations should also consider disabling DHCPv6 functionality on affected devices if the service is not critical, while maintaining proper network segmentation to limit the potential impact of successful attacks. The vulnerability aligns with CWE-129, which describes "Improper Validation of Array Index" and CWE-20, which covers "Improper Input Validation," highlighting the need for robust input sanitization and validation controls in network protocol implementations.