CVE-2017-6627 remediation guide
Cisco IOS and IOS XE Software
A vulnerability in the UDP processing code of Cisco IOS 15.1, 15.2, and 15.4 and IOS XE 3.14 through 3.18 could allow an unauthenticated, remote attacker to cause the input queue of an affected system to hold UDP packets, causing an interface queue wedge and a denial of service (DoS) condition. The vulnerability is due to Cisco IOS Software application changes that create UDP sockets and leave the sockets idle without closing them. An attacker could exploit this vulnerability by sending UDP packets with a destination port of 0 to an affected device. A successful exploit could allow the atta...
A verified fixed-version field is not available. Use the linked NVD and supporting references, then confirm the vendor-supported path before changing production systems.
Identify the affected asset
Confirm whether Cisco IOS and IOS XE Software is installed, record the deployed version and installation path, and identify exposed interfaces.
- Record the product name, package or appliance identifier, and installed version.
- Identify internet-facing, administrative, API, and internal access paths.
- Preserve the pre-change configuration and relevant service logs.
Validate the affected-version match
Compare the deployed version with the affected range: Cisco IOS and Cisco IOS XE, 15.1(2)gc, 15.1(2)gc1, 15.1(2)gc2, 15.1(4)gc, 15.1(4)gc1, 15.1(4)gc2, 15.2(1)gc, 15.2(1)gc1, 15.2(1)gc2, 15.2(2)gc, 15.2(3)gc, 15.2(3)gc1, 15.2(3r)gca, 15.2(4)gc, 15.2(4)gc1, 15.2(4)gc2, 15.2(4)gc3, 15.4(1)t, 15.4(1)t1. Treat incomplete inventory results as unresolved.
Prioritize with independent signals
CISA has listed this vulnerability in the Known Exploited Vulnerabilities catalog. Combine this signal with asset criticality, exposure, compensating controls, and business impact.
Apply supported remediation
Apply updates per vendor instructions.
Verify the result
Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.
- Confirm the expected version and package state.
- Run a functional health check for critical service paths.
- Review authentication, error, application, and security monitoring logs.
- Reassess exposure if the supported fix cannot be applied.
Operational boundary
This page does not replace the vendor advisory, support contract, change-management process, or recovery plan. Do not infer that an asset is unaffected from an incomplete inventory query or a missing fixed-version field.