Vulnerability identifier: #VU7365

Vulnerability risk: Low

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-6731

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco IOS XR
Operating systems & Components / Operating system

Vendor: Cisco Systems, Inc

Description
The vulnerability allows a remote unauthenticated attacker to cause DoS condition.

The weakness exists in Multicast Source Discovery Protocol (MSDP) ingress packet processing for Cisco IOS XR Software due to incorrect error handling of an MSDP packet that contains an error in the packet header. A remote attacker can send a malformed MSDP packet for an established MSDP session and cause the MSDP session to restart.

Successful exploitation of the vulnerability results in denial of service.

Mitigation
The vulnerability is addressed in the following versions:
6.3.1.19i.MCAST, 6.2.3.1i.MCAST, 6.2.2.17i.MCAST, 6.1.4.12i.MCAST.

Vulnerable software versions

Cisco IOS XR: 4.3.2.MCAST - 6.0.2

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170705-iosxr

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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