CVE intelligence and bounded remediation

CVE-2017-12236 — Cisco Ios Xe security vulnerability

Critical CVSS 9.8

A vulnerability in the implementation of the Locator/ID Separation Protocol (LISP) in Cisco IOS XE 3.2 through 16.5 could allow an unauthenticated, remote attacker using an x tunnel router to bypass authentication checks performed when registering an Endpoint Identifier (EID) to a Routing Locator (RLOC) in the map server/map resolver (MS/MR). The vulnerability is due to a logic error introduced via a code regression for the affected software. An attacker could exploit this vulnerability by sending specific valid map-registration requests, which will be accepted by the MS/MR even if the authentication keys do not match, to the affected software. A successful exploit could allow the attacker to inject invalid mappings of EIDs to RLOCs in the MS/MR of the affected software. This vulnerability affects Cisco devices that are configured with LISP acting as an IPv4 or IPv6 map server. This vulnerability affects Cisco IOS XE Software release trains 3.9E and Everest 16.4. Cisco Bug IDs: CSCvc18008.

Severity
Critical
CVSS
9.8 (3.0)
Published
2017-09-29
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-287

Affected products

  • cisco / ios_xe / 3.2.0ja
  • cisco / ios_xe / 3.9.1e
  • cisco / ios_xe / 16.5.1c

Matched remediation archetype

Authentication bypass and missing authentication

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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