Vulnerability identifier: #VU12067

Vulnerability risk: Medium

CVSSv3.1: 7.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-0239

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco ASR 5000 Series
Hardware solutions / Firmware

Vendor: Cisco Systems, Inc

Description
The vulnerability allows a remote unauthenticated attacker to cause DoS condition on the target system.

The weakness exists in the egress packet processing functionality due to the failure to properly check that the length of a packet to transmit does not exceed the maximum supported length of the network interface card (NIC). A remote attacker can send a specially crafted IP packet or a series of specially crafted IP fragments through an interface, cause the network interface to cease forwarding packets by either IPv4 or IPv6 network traffic.

Mitigation
Update to versions 21.4.M0.67801, 21.4.M0.67798, 21.4.M0.67671, 21.4.D0.67805, 21.4.D0.67675, 21.4.C0.68000, 21.4.0.68051, 21.4.0, 21.3.1.67739, 21.3.1, 21.1.v6.67740, 21.1.v6, 21.0.v4.67670 or 21.0.v4.

Vulnerable software versions

Cisco ASR 5000 Series: 21.0.V0.65819 - 21.4.0

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180418-staros

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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.