CVE-2014-3322 in IOS XR
Summary
by MITRE
Cisco IOS XR 4.3(.2) and earlier on ASR 9000 devices does not properly perform NetFlow sampling of IP packets, which allows remote attackers to cause a denial of service (chip and card hangs) via malformed (1) IPv4 or (2) IPv6 packets, aka Bug ID CSCuo68417.
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Analysis
by VulDB Data Team • 02/09/2022
Cisco IOS XR software running on ASR 9000 devices contains a critical vulnerability in the NetFlow sampling implementation that can be exploited to cause system-level denial of service conditions. This vulnerability affects versions 4.3.2 and earlier, where the system fails to properly process malformed IPv4 and IPv6 packets during NetFlow sampling operations. The flaw resides in the packet processing pipeline where the device attempts to sample network traffic for flow monitoring purposes, but encounters unexpected packet structures that cause the hardware components to become unresponsive.
The technical implementation of this vulnerability stems from insufficient input validation within the NetFlow sampling module of the IOS XR operating system. When malformed packets are received, the system's packet parser does not adequately handle edge cases or malformed packet headers that could cause the hardware sampling chips to enter an unrecoverable state. This issue specifically impacts the Network Processing Unit (NPU) and associated hardware components responsible for flow data collection. The vulnerability manifests as complete system hangs where the affected cards and chips cease to function properly, requiring manual intervention or device reboot to restore normal operations. The attack vector requires remote access to send specially crafted malformed packets to the vulnerable device, making it particularly dangerous for publicly accessible network equipment.
The operational impact of CVE-2014-3322 represents a severe availability threat to network infrastructure, as successful exploitation can result in complete service disruption across the affected ASR 9000 device. Network administrators may experience extended downtime while system recovery procedures are executed, potentially affecting multiple services dependent on the device's routing capabilities. The vulnerability affects both IPv4 and IPv6 packet types, expanding the attack surface and increasing the likelihood of successful exploitation. Organizations relying on these devices for critical network functions face significant risk of service degradation or complete network outages. This vulnerability aligns with CWE-129, Input Validation, and CWE-248, Uncaught Exception, as the system fails to properly validate incoming packet structures and handle malformed data gracefully. The attack pattern follows ATT&CK technique T1498.001, Direct Network Connection, where adversaries establish network connections to target systems to execute denial of service attacks.
Mitigation strategies for this vulnerability should include immediate implementation of IOS XR software updates to versions 4.3.3 or later, which contain patches addressing the NetFlow sampling flaw. Network administrators should also implement access control measures to limit direct exposure of vulnerable devices to untrusted networks, including firewall rules and network segmentation. Monitoring systems should be configured to detect unusual packet patterns that might indicate exploitation attempts, and baseline network behavior should be established to quickly identify anomalous traffic. Additionally, organizations should consider implementing redundant network paths and failover mechanisms to minimize the impact of potential service disruptions. The vulnerability demonstrates the critical importance of proper input validation and exception handling in network infrastructure software, as highlighted by industry best practices for secure coding and network security hardening.