CVE-2008-4963 in CatOS
Summary
by MITRE
Unspecified vulnerability in the VLAN Trunking Protocol (VTP) implementation on Cisco IOS and CatOS, when the VTP operating mode is not transparent, allows remote attackers to cause a denial of service (device reload or hang) via a crafted VTP packet sent to a switch interface configured as a trunk port.
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Analysis
by VulDB Data Team • 08/20/2019
The vulnerability described in CVE-2008-4963 represents a critical flaw in Cisco's VLAN Trunking Protocol implementation across both IOS and CatOS operating systems. This issue specifically affects network switches where VTP is configured in non-transparent modes, creating a significant attack surface that remote adversaries can exploit to disrupt network operations. The vulnerability stems from insufficient input validation within the VTP packet processing mechanism, allowing malicious actors to craft specially formatted packets that trigger unexpected behavior in the switch's operating system.
The technical exploitation of this vulnerability occurs through the manipulation of VTP packets transmitted to switch interfaces configured as trunk ports. When a switch receives a crafted VTP packet, the malformed data causes the device to enter an unstable state that ultimately results in either a complete device reload or system hang. This behavior demonstrates a classic buffer overflow or input validation failure pattern where the system fails to properly handle unexpected packet structures. The vulnerability affects the core network infrastructure by potentially rendering switches inoperable, thereby disrupting network connectivity and service availability for all devices relying on those network segments.
From an operational impact perspective, this vulnerability poses severe risks to enterprise network stability and availability. Network administrators face the potential for unplanned outages when attackers exploit this weakness, as the denial of service can affect entire network segments depending on the compromised switch's role in the network topology. The remote nature of the attack means that adversaries do not require physical access to network equipment, making the vulnerability particularly dangerous in environments where network switches are accessible from external networks. This weakness directly impacts the availability component of the CIA triad and can be classified under CWE-121, which addresses buffer overflow conditions that lead to system instability and potential denial of service scenarios.
The exploitation of this vulnerability aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to denial of service attacks and network infrastructure manipulation. Attackers can leverage this weakness to perform network disruption campaigns without requiring sophisticated tools or extensive network access privileges. The vulnerability also demonstrates characteristics consistent with network protocol exploitation techniques where malformed packets are used to trigger system instability. Organizations implementing network security measures should consider this vulnerability when developing their security posture and incident response plans, as it represents a fundamental weakness in network infrastructure that can be exploited to cause widespread service disruption.
Effective mitigation strategies for this vulnerability include implementing proper network segmentation to limit exposure of switches to untrusted networks, configuring VTP in transparent mode where appropriate to reduce attack surface, and applying the relevant Cisco security patches and updates. Network administrators should also consider implementing network access controls and monitoring for unusual VTP packet patterns that might indicate exploitation attempts. The vulnerability highlights the importance of regular security assessments and patch management programs to address known weaknesses in network infrastructure components. Additionally, implementing network intrusion detection systems that can identify malformed VTP packets may provide early warning capabilities for potential exploitation attempts.