Vulnerability identifier: #VU8683

Vulnerability risk: High

CVSSv3.1: 9.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2017-12240

CWE-ID: CWE-120

Exploitation vector: Network

Exploit availability: No

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

Vendor: Cisco Systems, Inc

Description
The vulnerability allows a remote attacker to cause execute arbitrary code on the target system.

The weakness exists due to a buffer overflow condition in the DHCP relay subsystem of Cisco IOS and Cisco IOS XE Software. A remote attacker can send a specially crafted DHCP Version 4 (DHCPv4) packet, execute arbitrary code and gain full control over the affected system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Cisco IOS: 12.2 - 15.5SN

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-dhcp

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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?

Yes. This vulnerability is being exploited in the wild.