Headline
CVE-2019-16027: Cisco Security Advisory: Cisco IOS XR Software Intermediate System-to-Intermediate System Denial of Service Vulnerability
A vulnerability in the implementation of the Intermediate System–to–Intermediate System (IS–IS) routing protocol functionality in Cisco IOS XR Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition in the IS–IS process. The vulnerability is due to improper handling of a Simple Network Management Protocol (SNMP) request for specific Object Identifiers (OIDs) by the IS–IS process. An attacker could exploit this vulnerability by sending a crafted SNMP request to the affected device. A successful exploit could allow the attacker to cause a DoS condition in the IS–IS process.
Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.htmlAdditionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC:
https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.htmlCustomers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
Cisco fixed this vulnerability in Cisco IOS XR Software Release 6.6.3. Cisco also plans to fix this vulnerability in Cisco IOS XR Software releases 7.0.2, 7.1.1, and 7.2.1.
Customers are advised to install the appropriate SMU as shown in the following table. Customers who require SMUs for other platforms and releases are advised to contact their support organization.
IOS XR Release
Platform
SMU Name
4.3.2
XR12000
c12k-4.3.2.CSCvr62342
5.2.5
NCS6K
ncs6k-5.2.5.CSCvr62342
6.1.2
ASR9K-PX
asr9k-px-6.1.2.CSCvr62342
6.1.3
ASR9K-PX
asr9k-px-6.1.3.CSCvr62342
6.1.3
NCS5K
ncs5k-6.1.3.CSCvr62342
6.1.3
NCS5500
ncs5500-6.1.3.CSCvr62342
6.1.4
ASR9K-PX
asr9k-px-6.1.4.CSCvr6234
6.1.4
CRS-PX
hfr-px-6.1.4.CSCvr62342
6.1.4
NCS5500
ncs5500-6.1.4.CSCvr62342
6.1.4
NCS5K
ncs5k-6.1.4.CSCvr62342
6.1.4
XRV9K
xrv9k-6.1.4.CSCvr62342
6.2.2
ASR9K-PX
asr9k-px-6.2.2.CSCvr62342
6.2.2
NCS6K
ncs6k-6.2.2.CSCvr62342
6.2.25
NCS5K
ncs5k-6.2.25.CSCvr62342
6.2.25
NCS6K
ncs6k-6.2.25.CSCvr62342
6.2.3
NCS5K
ncs5k-6.2.3.CSCvr62342
6.2.3
ASR9K-PX
asr9k-px-6.2.3.CSCvr62342
6.2.3
ASR9K-X64
asr9k-x64-6.2.3.CSCvr62342
6.2.3
CRS-PX
hfr-px-6.2.3.CSCvr62342
6.2.3
NCS5500
ncs5500-6.2.3.CSCvr62342
6.2.3
XRV9K
xrv9k-6.2.3.CSCvr62342
6.2.3
NCS6K
ncs6k-6.2.3.CSCvr62342
6.3.15
NCS5500
ncs5500-6.3.15.CSCvr62342
6.3.2
ASR9K-PX
asr9k-px-6.3.2.CSCvr62342
6.3.2
ASR9K-X64
asr9k-x64-6.3.2.CSCvr62342
6.3.3
ASR9K-X64
asr9k-x64-6.3.3.CSCvr62342
6.3.3
ASR9K-PX
asr9k-px-6.3.3.CSCvr62342
6.3.3
NCS5K
ncs5k-6.3.3.CSCvr62342
6.3.3
NCS540
ncs540-6.3.3.CSCvr62342
6.3.3
NCS5500
ncs5500-6.3.3.CSCvr62342
6.3.3
NCS6K
ncs6k-6.3.3.CSCvr62342
6.4.2
ASR9K-PX
asr9k-px-6.4.2.CSCvr62342
6.4.2
ASR9K-X64
asr9k-x64-6.4.2.CSCvr62342
6.4.2
CRS-PX
hfr-px-6.4.2.CSCvr62342
6.4.2
NCS5K
ncs5k-6.4.2.CSCvr62342
6.4.2
NCS6K
ncs6k-6.4.2.CSCvr62342
6.4.2
XRV9K
xrv9k-6.4.2.CSCvr62342
6.5.2
ASR9K-PX
asr9k-px-6.5.2.CSCvr62342
6.5.2
ASR9K-X64
asr9k-x64-6.5.2.CSCvr62342
6.5.2
NCS5K
ncs5k-6.5.2.CSCvr62342
6.5.2
NCS5500
ncs5500-6.5.2.CSCvr62342
6.5.3
ASR9K-X64
asr9k-x64-6.5.3.CSCvr62342
6.5.3
NCS5500
ncs5500-6.5.3.CSCvr62342
6.5.3
NCS540
ncs540-6.5.3.CSCvr62342
6.5.3
NCS5K
ncs5k-6.5.3.CSCvr62342
6.5.3
ASR9K-PX
asr9k-px-6.5.3.CSCvr62342
6.5.3
XRV9K
xrv9k-6.5.3.CSCvr62342
6.6.1
NCS5500
ncs5500-6.6.1.CSCvr62342
6.6.2
ASR9K-PX
asr9k-px-6.6.2.CSCvr62342
6.6.2
ASR9K-X64
asr9k-x64-6.6.2.CSCvr62342
6.6.2
XRV9K
xrv9k-6.6.2.CSCvr62342
6.6.25
NCS5500
ncs5500-6.6.25.CSCvr62342
6.6.25
NCS540
ncs540-6.6.25.CSCvr62342
6.6.25
NCS560
ncs560-6.6.25.CSCvr62342
To download the SMUs from the Software Center on Cisco.com, do the following:
- Click Browse All.
- Choose IOS and NX-OS Software > IOS XR > IOS XR Software > Optical Networking or Routers.
- Choose a specific product and model from the right pane of the product selector.
- Choose a release from the left pane of the product page.