Cisco NX-OS 13.0(1k) on Nexus 9000 DHCPv6 Packet resource consumption

Summaryinfo

A vulnerability classified as problematic has been found in Cisco NX-OS 13.0(1k) on Nexus 9000. Affected by this issue is some unknown functionality of the component DHCPv6. The manipulation as part of Packet leads to resource consumption. This vulnerability is referenced as CVE-2018-0372. Remote exploitation of the attack is possible. No exploit is available. It is recommended to apply restrictive firewalling.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Cisco NX-OS 13.0(1k) on Nexus 9000 (Router Operating System). This issue affects some unknown processing of the component DHCPv6. The manipulation as part of a Packet leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability. The summary by CVE is:

A vulnerability in the DHCPv6 feature of the Cisco Nexus 9000 Series Fabric Switches in Application-Centric Infrastructure (ACI) Mode could allow an unauthenticated, remote attacker to cause the device to run low on system memory, which could result in a Denial of Service (DoS) condition on an affected system. The vulnerability is due to improper memory management when DHCPv6 packets are received on an interface of the targeted device. An attacker could exploit this vulnerability by sending a high number of malicious DHCPv6 packets to be processed by an affected device. A successful exploit could allow the attacker to cause the system to run low on memory, which could cause an eventual reboot of an affected device. The vulnerability only applies to IPv6 protocol packets and not for IPv4 protocol packets. This vulnerability affects Cisco Nexus 9000 Series Fabric Switches in ACI Mode running software version 13.0(1k). The vulnerability can only be exploited when unicast routing is enabled on the Bridge Domain (BD). DHCP and DHCP relay do not have to be configured for the vulnerability to be exploited. Cisco Bug IDs: CSCvg38918.

The bug was discovered 07/18/2018. The weakness was published 07/18/2018 as cisco-20180718-nexus-9000-dos as confirmed advisory (Website). The advisory is shared at tools.cisco.com. The identification of this vulnerability is CVE-2018-0372 since 11/27/2017. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

The commercial vulnerability scanner Qualys is able to test this issue with plugin 316301 (Cisco Nexus 9000 Series Fabric Switches Application-Centric Infrastructure Mode DHCP Version 6 Denial of Service Vulnerability(cisco-20180718-nexus-9000-dos)).

Addressing this vulnerability is possible by firewalling .

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Productinfo

Type

• Router Operating System

Vendor

• Cisco

Name

• NX-OS

Version

• 13.0(1k)

License

• commercial

Website

• Vendor: https://www.cisco.com/

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