Denial of service in Cisco FXOS, IOS XR and NX-OS

1) Integer overflow

EUVDB-ID: #VU49026

Risk: Low

CVSSv4.0: 4.9 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-3120

CWE-ID: CWE-190 - Integer overflow

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to integer overflow in the Cisco Discovery Protocol implementation. A remote attacker on the local network can send a specially crafted Cisco Discovery Protocol packet, trigger integer overflow and cause a denial of service condition on the target system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Cisco FXOS: - - 2.7

Cisco IOS XR: 5.2.5 - 7.0.1

Cisco NX-OS: - - 14.2

Cisco MDS 9000 Series Multilayer Switches: 6.2.1 - 8.4.2.9

Cisco IOS XRv 9000 Router: All versions

Cisco Firepower 9300 Security Appliance: 2.4.200.10

Cisco Firepower 4100 Series Next-Generation Firewall: All versions

Cisco Carrier Routing System: All versions

Cisco ASR 9000 Series Aggregation Services Routers: 6.1.3

Cisco Network Convergence System 6000 Series Routers: All versions

Network Convergence System 5500 Series: All versions

Cisco Network Convergence System 5000 Series: All versions

Cisco Network Convergence System 1000 Series: All versions

Cisco Network Convergence System 560 Series Routers: All versions

Cisco Network Convergence System 540 Series Routers: All versions

Cisco Nexus 9000 Series Switches NX-OS Mode: All versions

Cisco Nexus 9000 Series Switches in ACI Mode: All versions

Cisco Nexus 7000 Series Switches: All versions

Cisco Nexus 6000 Series Switches: All versions

Nexus 5600 Platform Switches: All versions

Nexus 5500 Platform Switches: All versions

Cisco Nexus 3000 Series Switches: All versions

Nexus 1000V Switch for VMware vSphere: 5.2.1 SV5.1.2

Nexus 1000V Switch for Microsoft Hyper-V: All versions

Nexus 1000 Virtual Edge for VMware vSphere: All versions

UCS 6400 Series Fabric Interconnects: - - 4.0

UCS 6300 Series Fabric Interconnects: - - 4.0

UCS 6200 Series Fabric Interconnects: - - 4.0

CPE2.3

• cpe:2.3:o:cisco_systems:cisco_fxos:*:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_fxos:2.2:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_fxos:2.3:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_ios_xr:5.2.5:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_ios_xr:6.4.2:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_ios_xr:6.5.3:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_ios_xr:6.6:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_ios_xr:6.6.12:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_ios_xr:6.6.25:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_ios_xr:7.0:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_nx-os:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_mds_9000_series_multilayer_switches:6.2.1:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_ios_xrv_9000_router:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_firepower_9300_security_appliance:2.4.200.10:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_firepower_4100_series_next-generation_firewall:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_carrier_routing_system:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_asr_9000_series_aggregation_services_routers:6.1.3:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_network_convergence_system_6000_series_routers:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:network_convergence_system_5500_series:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_network_convergence_system_5000_series:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_network_convergence_system_1000_series:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_network_convergence_system_560_series_routers:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_network_convergence_system_540_series_routers:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_nexus_9000_series_switches_nx-os_mode:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_nexus_9000_series_switches_in_aci_mode:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_nexus_7000_series_switches:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_nexus_6000_series_switches:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:nexus_5600_platform_switches:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:nexus_5500_platform_switches:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_nexus_3000_series_switches:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:nexus_1000v_switch_for_vmware_vsphere:5.2.1 SV5.1.2:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:nexus_1000v_switch_for_microsoft_hyper-v:*:*:*:*:*:*:*:*
• cpe:2.3:a:cisco_systems:nexus_1000_virtual_edge_for_vmware_vsphere:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:ucs_6400_series_fabric_interconnects:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:ucs_6300_series_fabric_interconnects:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:ucs_6200_series_fabric_interconnects:*:*:*:*:*:*:*:*

External links

https://packetstormsecurity.com/files/156203/Cisco-Discovery-Protocol-CDP-Remote-Device-Takeover.html
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200205-fxnxos-iosxr-cdp-dos

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.