#VU8683 Buffer overflow in Cisco IOS - CVE-2017-12240

Vulnerability identifier: #VU8683

Vulnerability risk: High

CVSSv4.0: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber]

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 - 12.2.33, 12.3, 12.4 - 12.4.24 T4, 15.0, 15.1(2.0) - 15.1, 15.2EA - 15.2(5c)E, 15.3S - 15.3, 15.4S - 15.4.2 S, 15.5SN - 15.5.3 S2.9

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External links
https://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.