CVE-2018-0165 in IOS XE
Summary
by MITRE
A vulnerability in the Internet Group Management Protocol (IGMP) packet-processing functionality of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to exhaust buffers on an affected device, resulting in a denial of service (DoS) condition, aka a Memory Leak. The vulnerability is due to the affected software insufficiently processing IGMP Membership Query packets that are sent to an affected device. An attacker could exploit this vulnerability by sending a large number of IGMP Membership Query packets, which contain certain values, to an affected device. A successful exploit could allow the attacker to exhaust buffers on the affected device, resulting in a DoS condition that requires the device to be reloaded manually. This vulnerability affects: Cisco Catalyst 4500 Switches with Supervisor Engine 8-E, if they are running Cisco IOS XE Software Release 3.x.x.E and IP multicast routing is configured; Cisco devices that are running Cisco IOS XE Software Release 16.x, if IP multicast routing is configured. Cisco Bug IDs: CSCuw09295, CSCve94496.
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Analysis
by VulDB Data Team • 02/06/2021
The vulnerability described in CVE-2018-0165 represents a critical memory exhaustion issue within Cisco IOS XE Software that specifically targets the Internet Group Management Protocol implementation. This flaw manifests in the improper handling of IGMP Membership Query packets, which are fundamental components of multicast routing operations in network infrastructure devices. The vulnerability affects Cisco Catalyst 4500 Switches equipped with Supervisor Engine 8-E running IOS XE Software releases 3.x.x.E and devices operating on IOS XE Software Release 16.x, provided that IP multicast routing is enabled. The root cause lies in the insufficient validation and processing mechanisms within the IGMP packet handling code, creating a memory leak condition that can be exploited through crafted packet sequences.
The technical exploitation of this vulnerability requires an adjacent attacker who can send a high volume of specially crafted IGMP Membership Query packets to the target device. These packets contain specific values that trigger the flawed buffer management logic within the IOS XE software stack. When the affected device processes these malformed packets, the insufficient input validation causes the system to allocate memory buffers without proper cleanup mechanisms, leading to progressive memory consumption. The vulnerability operates at the network protocol level, specifically targeting the multicast routing functionality that relies heavily on IGMP for managing group membership in multicast networks. This type of attack falls under the category of resource exhaustion attacks and can be classified as a CWE-400 vulnerability, specifically related to unspecified memory errors in protocol implementations.
The operational impact of CVE-2018-0165 is severe and directly affects network availability through denial of service conditions. Once successfully exploited, the vulnerability causes the target device to consume all available buffer resources, forcing the system into a degraded state where legitimate multicast traffic cannot be processed. Network administrators must manually reload the affected devices to restore normal operation, creating significant downtime and potential service disruption for multicast-dependent applications. The vulnerability's impact is particularly concerning in enterprise network environments where multicast routing is commonly used for streaming media, voice over IP services, and other time-sensitive applications. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 (Endpoint Denial of Service) and T1595.001 (Network Denial of Service), representing a sophisticated attack vector that leverages protocol implementation flaws to achieve system compromise.
Mitigation strategies for this vulnerability require immediate patching of affected Cisco IOS XE Software versions through official Cisco security advisories and software updates. Network administrators should also implement access control measures to restrict physical or network access to devices running affected software, as the vulnerability requires adjacent network access for exploitation. Monitoring network traffic for unusual patterns of IGMP Membership Query packets can help detect potential exploitation attempts. Cisco has provided specific bug IDs CSCuw09295 and CSCve94496 that document the exact nature of the memory leak and associated fixes. Organizations should also consider implementing network segmentation strategies to isolate critical multicast services and reduce the attack surface. The vulnerability demonstrates the importance of proper input validation in protocol implementations and highlights the need for comprehensive security testing of network infrastructure software, particularly in areas related to multicast routing and group management protocols.