Multiple vulnerabilities in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges on an affected device. For more information about these vulnerabilities, see the Details section of this advisory. Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-lldp This advisory is part of the March 28, 2018, release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication, which includes 20 Cisco Security Advisories that describe 22 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: March 2018 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.
Multiple vulnerabilities in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges on an affected device.
For more information about these vulnerabilities, see the Details section of this advisory.
Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-lldp
This advisory is part of the March 28, 2018, release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication, which includes 20 Cisco Security Advisories that describe 22 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: March 2018 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.
These vulnerabilities affect Cisco devices that are running a vulnerable release of Cisco IOS Software, Cisco IOS XE Software, or Cisco IOS XR Software and are configured to use LLDP. The default state of the LLDP feature is platform- and release-dependent.
For information about which Cisco IOS, IOS XE, and IOS XR Software releases are vulnerable, see the Fixed Software section of this advisory.
To determine whether a device is configured to use LLDP, administrators can log in to the device and use the show lldp command in the CLI. If the device is configured to use LLDP, the output of the command will be similar to the following:
Vulmon
Router> show lldp
Global LLDP Information:
Status: ACTIVE
LLDP advertisements are sent every 30 seconds
LLDP hold time advertised is 120 seconds
LLDP interface reinitialisation delay is 2 seconds
If use of LLDP is configured for only specific interfaces of a device, administrators can instead use the show lldp interface command in the CLI to determine which interfaces are configured to use LLDP.
To determine which Cisco IOS Software release is running on a device, administrators can log in to the device, use the show version command in the CLI, and then refer to the system banner that appears. If the device is running Cisco IOS Software, the system banner displays text similar to Cisco Internetwork Operating System Software or Cisco IOS Software. The banner also displays the installed image name in parentheses, followed by the Cisco IOS Software release number and release name. Some Cisco devices do not support the show version command or may provide different output.
The following example shows the output of the command for a device that is running Cisco IOS Software Release 15.5(2)T1 and has an installed image name of C2951-UNIVERSALK9-M:
Router> show version
Cisco IOS Software, C2951 Software (C2951-UNIVERSALK9-M), Version 15.5(2)T1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2015 by Cisco Systems, Inc.
Compiled Mon 22-Jun-15 09:32 by prod_rel_team
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.
.
For information about the naming and numbering conventions for Cisco IOS Software releases, see the Cisco IOS and NX-OS Software Reference Guide.
To determine which Cisco IOS XE Software release is running on a device, administrators can log in to the device, use the show version command in the CLI, and then refer to the system banner that appears. If the device is running Cisco IOS XE Software, the system banner displays Cisco IOS Software, Cisco IOS XE Software, or similar text.
The following example shows the output of the command for a device that is running Cisco IOS XE Software Release 16.2.1 and has an installed image name of CAT3K_CAA-UNIVERSALK9-M:
ios-xe-device# show version
Cisco IOS Software, Catalyst L3 Switch Software (CAT3K_CAA-UNIVERSALK9-M), Version Denali 16.2.1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2016 by Cisco Systems, Inc.
Compiled Sun 27-Mar-16 21:47 by mcpre
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.
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For information about the naming and numbering conventions for Cisco IOS XE Software releases, see the Cisco IOS and NX-OS Software Reference Guide.
To determine which Cisco IOS XR Software release is running on a device, administrators can log in to the device, use the show version command in the CLI, and then refer to the system banner that appears. If the device is running Cisco IOS XR Software, the system banner displays Cisco IOS XR Software or similar text. In addition, the System image file is field displays the location and name of the system image file that is running on the device, followed by the name of the hardware product.
The following example shows the output of the show version command for a device that is running Cisco IOS XR Software Release 5.3.4:
RP/0/RSP0/CPU0:ASR9001# show version
Wed Jan 24 01:32:32.751 EST
Cisco IOS XR Software, Version 5.3.4[Default]
Copyright (c) 2017 by Cisco Systems, Inc.
ROM: System Bootstrap, Version 2.04(20140227:092320) [ASR9K ROMMON],
ASR9001 uptime is 6 hours, 17 minutes
System image file is "bootflash:disk0/asr9k-os-mbi-5.3.4.sp4-1.0.0/0x100000/mbiasr9k-rp.vm"
cisco ASR9K Series (P4040) processor with 8388608K bytes of memory.
P4040 processor at 1500MHz, Revision 2.0
ASR-9001 Chassis
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Two vulnerabilities in the LLDP subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a DoS condition or execute arbitrary code with elevated privileges.
Details about the vulnerabilities are as follows.
A vulnerability in the LLDP subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an adjacent, unauthenticated attacker to cause a DoS condition or execute arbitrary code with elevated privileges.
The vulnerability is due to improper error handling of malformed LLDP messages. An attacker who is connected directly to an interface of an affected device could exploit this vulnerability by submitting an LLDP protocol data unit (PDU) that is designed to trigger the issue. If successful, an exploitable buffer overflow condition may occur that could result in a DoS condition or the attacker gaining the ability to execute arbitrary code with elevated privileges.
The Common Vulnerabilities and Exposures (CVE) ID for this vulnerability is: CVE-2018-0167
The Security Impact Rating (SIR) for this vulnerability is: High
The Cisco bug IDs for this vulnerability are: CSCvd73487 (Cisco IOS and IOS XE Software) and CSCuo17183 (Cisco IOS XR Software)
A vulnerability in the LLDP subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an adjacent, unauthenticated attacker to cause a DoS condition or execute arbitrary code with elevated privileges.
The vulnerability is due to improper handling of certain fields in an LLDP message. An attacker who is connected directly to an interface of an affected device could exploit this vulnerability by submitting an LLDP PDU that is designed to prime the device for exploitation. An attacker must then convince an authenticated user to execute a specific show command in the CLI of the affected device. If successful, the attacker could cause a DoS condition or gain the ability to execute arbitrary code with elevated privileges.
The CVE ID for this vulnerability is: CVE-2018-0175
The SIR for this vulnerability is: High
The Cisco bug ID for this vulnerability is: CSCvd73664
Cisco has released free software updates that address the vulnerabilities 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.html
Additionally, 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.html
Customers 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.
To help customers determine their exposure to vulnerabilities in Cisco IOS and IOS XE Software, Cisco provides a tool, the Cisco IOS Software Checker, that identifies any Cisco Security Advisories that impact a specific software release and the earliest release that fixes the vulnerabilities described in each advisory (“First Fixed”). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities described in all the advisories identified (“Combined First Fixed”).
Customers can use this tool to perform the following tasks:
To determine whether a release is affected by any published Cisco Security Advisory, use the Cisco IOS Software Checker on Cisco.com or enter a Cisco IOS Software or Cisco IOS XE Software release-for example, 15.1(4)M2 or 3.13.8S-in the following field:
For a mapping of Cisco IOS XE Software releases to Cisco IOS Software releases, refer to the Cisco IOS XE 2 Release Notes, Cisco IOS XE 3S Release Notes, or Cisco IOS XE 3SG Release Notes, depending on the Cisco IOS XE Software release.
The following table lists major software release trains of Cisco IOS XR Software, indicates whether a release train is affected by the vulnerabilities described in this advisory and, if applicable, the first minor release that includes the fix for these vulnerabilities. Customers should migrate to an appropriate release as indicated in the following table:
| Software Train |
First Fixed Release |
Recommended Release |
| 4.1 | No fix - migrate |
Migrate to 5.3.4 |
| 4.2 | No fix - migrate |
Migrate to 5.3.4 |
| 4.3 | No fix - migrate |
Migrate to 5.3.4 |
| 5.0 |
No fix - migrate |
Migrate to 5.3.4 |
| 5.1 | 5.1.3 | 5.1.3 |
| 5.2 | Not vulnerable |
Not vulnerable |
| 5.3 |
Not vulnerable |
Not vulnerable |
| 6.0 | Not vulnerable |
Not vulnerable |
| 6.1 | Not vulnerable |
Not vulnerable |
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.
These vulnerabilities were found during the resolution of a Cisco TAC support case.
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.1 | Updated the metadata to indicate that multiple legacy Cisco IOS Software images are not vulnerable. | - | Final | 2018-May-02 |
| 1.0 | Initial public release. | - | Final | 2018-March-28 |
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