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AUSCERT External Security Bulletin Redistribution
ESB-2018.0912.2
Cisco IOS, IOS XE, and IOS XR Software Link Layer Discovery
Protocol Buffer Overflow Vulnerabilities
10 January 2023
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco IOS
Cisco IOS XE
Cisco IOS XR
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Increased Privileges -- Remote/Unauthenticated
Denial of Service -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2018-0175 CVE-2018-0167
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-lldp
Revision History: January 10 2023: Vendor Update
March 29 2018: Initial Release
- --------------------------BEGIN INCLUDED TEXT--------------------
Cisco IOS, IOS XE, and IOS XR Software Link Layer Discovery Protocol Buffer
Overflow Vulnerabilities
Priority: High
Advisory ID: cisco-sa-20180328-lldp
First Published: 2018 March 28 16:00 GMT
Last Updated: 2022 December 15 22:19 GMT
Version 1.2: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCuo17183 CSCvd73487 CSCvd73664
CVE Names: CVE-2018-0167 CVE-2018-0175
CVSS Score:
8.8 AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
Summary
o 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://sec.cloudapps.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 .
Affected Products
o Vulnerable Products
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.
Assessing the LLDP Configuration
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:
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.
Determining the Cisco IOS Software Release
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
.
.
.
For information about the naming and numbering conventions for Cisco IOS
Software releases, see the Cisco IOS and NX-OS Software Reference Guide .
Determining the Cisco IOS XE Software Release
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
.
.
.
For information about the naming and numbering conventions for Cisco IOS XE
Software releases, see the Cisco IOS and NX-OS Software Reference Guide .
Determining the Cisco IOS XR Software Release
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
.
.
.
Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by these
vulnerabilities.
Cisco has confirmed that these vulnerabilities do not affect Cisco NX-OS
Software.
Details
o 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.
Link Layer Discovery Protocol Buffer Overflow Vulnerability
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)
Link Layer Discovery Protocol Format String Vulnerability
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
Workarounds
o There are no workarounds that address these vulnerabilities.
Fixed Software
o 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.
Cisco IOS XR Software
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
Exploitation and Public Announcements
o In March 2022, the Cisco Product Security Incident Response Team (PSIRT)
became aware of additional attempted exploitation of this vulnerability in
the wild. Cisco continues to strongly recommend that customers upgrade to a
fixed software release to remediate this vulnerability.
Source
o These vulnerabilities were found during the resolution of a Cisco TAC
support case.
Cisco Security Vulnerability Policy
o 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.
Subscribe to Cisco Security Notifications
o Subscribe
Related to This Advisory
o Cisco Event Response: March 2018 Semiannual Cisco IOS and IOS XE Software
Security Advisory Bundled Publication
Cisco Security Blog: Cisco IOS and IOS XE Software Bundled Publication
March 2018
URL
o https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-lldp
Revision History
o +---------+------------------------+---------------+--------+-------------+
| Version | Description | Section | Status | Date |
+---------+------------------------+---------------+--------+-------------+
| | Updated exploitation | Exploitation | | |
| 1.2 | information. | and Public | Final | 2022-DEC-15 |
| | | Announcements | | |
+---------+------------------------+---------------+--------+-------------+
| | Updated the metadata | | | |
| | to indicate that | | | |
| 1.1 | multiple legacy Cisco | - | Final | 2018-MAY-02 |
| | IOS Software images | | | |
| | are not vulnerable. | | | |
+---------+------------------------+---------------+--------+-------------+
| 1.0 | Initial public | - | Final | 2018-MAR-28 |
| | release. | | | |
+---------+------------------------+---------------+--------+-------------+
Legal Disclaimer
o THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND
OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT
OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES
THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A standalone copy or paraphrase of the text of this document that omits the
distribution URL is an uncontrolled copy and may lack important information
or contain factual errors. The information in this document is intended for
end users of Cisco products.
- --------------------------END INCLUDED TEXT--------------------
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