CVE-2009-2189 in Time Capsule
Summary
by MITRE
The ICMPv6 implementation on the Apple Time Capsule, AirPort Extreme Base Station, and AirPort Express Base Station with firmware before 7.5.2 does not limit the rate of (1) Router Advertisement and (2) Neighbor Discovery packets, which allows remote attackers to cause a denial of service (resource consumption and device restart) by sending many packets.
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Analysis
by VulDB Data Team • 10/07/2021
The vulnerability described in CVE-2009-2189 represents a critical flaw in the network stack implementation of Apple's wireless networking hardware, specifically affecting Time Capsule, AirPort Extreme Base Station, and AirPort Express Base Station devices running firmware versions prior to 7.5.2. This issue stems from inadequate rate limiting mechanisms within the Internet Control Message Protocol version 6 (ICMPv6) implementation, which is fundamental to IPv6 network operations and device communication. The flaw manifests in two primary areas: Router Advertisement and Neighbor Discovery packet handling, both of which are essential components of IPv6 network configuration and device discovery processes.
The technical implementation flaw involves the absence of proper packet rate limiting controls within the ICMPv6 processing subsystem of these networking devices. Router Advertisement messages are used by routers to broadcast information about network topology and configuration parameters to hosts on the network, while Neighbor Discovery packets facilitate address resolution and network connectivity maintenance. Without rate limiting, these packets can be sent in massive quantities from remote attackers, leading to excessive resource consumption within the device's processing capabilities. This vulnerability aligns with CWE-770, which describes inadequate resource management where an application fails to properly limit resource consumption, and represents a classic example of a resource exhaustion attack pattern.
The operational impact of this vulnerability is severe and directly translates to a denial of service condition that can completely disrupt network services. When an attacker floods the affected devices with excessive Router Advertisement and Neighbor Discovery packets, the hardware's processing capabilities become overwhelmed, leading to resource exhaustion and subsequent device restarts. This creates a persistent disruption of network services for all connected devices, effectively rendering the wireless access point unusable until manual intervention or device reboot occurs. The vulnerability demonstrates how seemingly benign network protocols can be weaponized to create significant operational disruption, particularly in enterprise environments where wireless infrastructure reliability is paramount.
The attack vector for this vulnerability is particularly concerning as it requires no authentication or specialized access privileges, making it accessible to any remote attacker capable of sending ICMPv6 packets to the affected devices. This characteristic places the vulnerability in the ATT&CK framework under the T1499.004 technique for "Network Denial of Service" and aligns with the broader category of "Resource Exhaustion" attacks. Organizations using affected Apple networking hardware should immediately implement firmware updates to version 7.5.2 or later, which includes proper rate limiting controls for ICMPv6 packet processing. Additional mitigations may include network-level filtering of ICMPv6 traffic, implementation of intrusion detection systems to monitor for anomalous packet patterns, and network segmentation to limit the attack surface of these vulnerable devices. The vulnerability also highlights the importance of regular firmware updates and proper network monitoring to identify and remediate similar implementation flaws in network infrastructure components.