CVE-2002-2239 in IOS
Summary
by MITRE
The Cisco Optical Service Module (OSM) for the Catalyst 6500 and 7600 series running Cisco IOS 12.1(8)E through 12.1(13.4)E allows remote attackers to cause a denial of service (hang) via a malformed packet.
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Analysis
by VulDB Data Team • 08/27/2019
The vulnerability identified as CVE-2002-2239 affects the Cisco Optical Service Module OSM operating within Cisco Catalyst 6500 and 7600 series switches running specific versions of Cisco IOS software. This represents a critical denial of service weakness that can be exploited remotely by malicious actors to disrupt network operations. The affected software versions span from 12.1(8)E through 12.1(13.4)E, indicating a substantial release range where network administrators must remain vigilant. The vulnerability specifically targets the packet processing mechanisms within the optical service module, which serves as a crucial component for fiber optic network connectivity and service delivery in enterprise and service provider environments.
The technical flaw manifests through improper handling of malformed packets within the OSM's packet processing pipeline. When a specially crafted malformed packet is transmitted to the affected switch, the system fails to properly validate or process the packet structure, leading to a complete system hang or crash. This vulnerability operates at the network protocol level where the switch's operating system fails to implement adequate input validation mechanisms. The flaw essentially allows an attacker to send packets that contain malformed data structures or unexpected values that cause the switch's packet processing engine to enter an undefined state, resulting in system instability. This type of vulnerability falls under the CWE-129 weakness category, which encompasses issues related to improper validation of input data, specifically concerning buffer overflows and malformed data handling.
The operational impact of this vulnerability extends far beyond simple network disruption, as the Catalyst 6500 and 7600 series switches serve as core infrastructure components in enterprise networks and service provider environments. When these switches experience a denial of service condition due to malformed packet attacks, network traffic flows are interrupted, potentially causing cascading failures throughout the connected network topology. The affected optical service modules are critical for high-speed fiber optic communications, making this vulnerability particularly dangerous in environments where network reliability is paramount. Organizations may experience significant downtime, service degradation, and potential financial losses due to the disruption of critical network services. The remote nature of the attack means that adversaries can exploit this vulnerability from outside the network perimeter, eliminating the need for physical access or insider knowledge of network configurations.
Cisco has released security advisories and patches addressing this vulnerability, emphasizing the importance of immediate software upgrades for affected systems. Network administrators should implement the recommended IOS software versions that contain fixes for this issue, typically involving enhanced packet validation routines and improved error handling mechanisms within the OSM processing modules. The mitigation strategy involves not only software updates but also network monitoring to detect potential exploitation attempts through malformed packet traffic patterns. Organizations should consider implementing network access controls and intrusion detection systems to identify and block suspicious packet flows that could indicate exploitation attempts. This vulnerability aligns with ATT&CK technique T1498, which involves network denial of service attacks, and demonstrates how legacy network infrastructure components can remain vulnerable to exploitation even in well-established enterprise environments where security updates may not be consistently applied.