#VU8688 Authentication bypass in Cisco IOS XE - CVE-2017-12236

Vulnerability identifier: #VU8688

Vulnerability risk: Low

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-12236

CWE-ID: CWE-284

Exploitation vector: Network

Exploit availability: No

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

Vendor: Cisco Systems, Inc

Description
The vulnerability allows a remote attacker to bypass authentication on the target system.

The weakness exists in the implementation of the Locator/ID Separation Protocol (LISP) in Cisco IOS XE Software due to a logic error introduced via a code regression. A remote attacker can send specific valid map-registration requests, which will be accepted by the MS/MR even if the authentication keys do not match, inject invalid mappings of EIDs to RLOCs in the MS/MR of the affected software and bypass authentication.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Cisco IOS XE: 3.2, 3.3, 3.4, 3.5, 3.6, 3.7E, 3.7, 3.8E, 3.8, 3.9E, 3.9, 3.10S - 3.10, 3.11, 3.12, 3.13, 3.14, 3.15S, 3.15, 3.16S, 3.16, 3.16.1aS, 3.17S, 3.17, 3.18, 16.1.2, 16.2.0 - 16.2.1.25, 16.3.0 - 16.3.1, 16.4.0.37 - 16.4.1

---

External links
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-lisp

---

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.