Denial of service in Cisco Network Convergence System 5500 Series

1) Denial of service

EUVDB-ID: #VU6987

Risk: Low

CVSSv3.1: 5.2 [CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-6666

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows local authenticated attacker to cause DoS condition on the target system.

The weakness exists in the forwarding component of Cisco IOS XR Software for Cisco Network Convergence System (NCS) 5500 Series Routers due to adjacency information for a Traffic Engineering (TE) tunnel's physical source interface is not propagated to hardware after the adjacency is lost. A local attacker can log in to the router's CLI with administrator privileges, issue the clear arp-cache command and cause the router to stop forwarding data traffic across Traffic Engineering (TE) tunnels.

Successful exploitation of the vulnerability results in denial of service.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Network Convergence System 5500 Series: 6.2.11.BASE

External links

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170607-ncs

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected device in order to exploit this vulnerability.

The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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