A vulnerability in the IOx application environment of multiple Cisco platforms could allow an unauthenticated, remote attacker to cause the IOx web server to stop processing HTTPS requests, resulting in a denial of service (DoS) condition. The vulnerability is due to a Transport Layer Security (TLS) implementation issue. An attacker could exploit this vulnerability by sending crafted TLS packets to the IOx web server on an affected device. A successful exploit could allow the attacker to cause the IOx web server to stop processing HTTPS requests, resulting in a DoS condition. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190925-iox This advisory is part of the September 25, 2019, release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication, which includes 12 Cisco Security Advisories that describe 13 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: September 2019 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.
A vulnerability in the IOx application environment of multiple Cisco platforms could allow an unauthenticated, remote attacker to cause the IOx web server to stop processing HTTPS requests, resulting in a denial of service (DoS) condition.
The vulnerability is due to a Transport Layer Security (TLS) implementation issue. An attacker could exploit this vulnerability by sending crafted TLS packets to the IOx web server on an affected device. A successful exploit could allow the attacker to cause the IOx web server to stop processing HTTPS requests, resulting in a DoS condition.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190925-iox
This advisory is part of the September 25, 2019, release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication, which includes 12 Cisco Security Advisories that describe 13 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: September 2019 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.
This vulnerability affects the following Cisco products if they are configured with the Cisco IOx application environment and are running a software release earlier than the first fixed release for that device:
For more information about which software releases are vulnerable, see the Fixed Software section of this advisory.
Administrators can see the status of IOx functionality by examining the device in Cisco IoT Field Network Director or by accessing the IOx (Linux) terminal and using the monit summary CLI command, as shown in the following example:
Vulmon
#monit summary
If the output contains Process ‘caf’ Running, as shown in the following example, the device is vulnerable:
Process 'caf' Running
Administrators can see the status of IOx functionality by using the show iox host list detail | include IOX Server is running CLI command, as shown in the following example:
CGR1000#show iox host list detail | include IOX Server is running
IOX Server is running. Process ID: 305
CGR1000#
On the Cisco IC3000, IOx functionality is enabled by default. Administrators can see the status of IOx functionality by using the show iox summary CLI command, as shown in the following example:
ic3k#show iox summary
IOx Infrastructure Summary:
---------------------------
eid: IC3000-2C2F-K9+FOC2227Y304
pfm: IC3000-2C2F-K9
s/n: FOC2227Y304
images: Lnx: 1.0.1., IOx: 1.7.0:r/1.7.0.0:fc6e9cf
boot: 2018-09-17 17:37:55
time: 2018-09-18 18:07:28
load: 18:07:28 up 1 day, 29 min, 0 users, load average: 0.32, 0.11, 0.02
memory: ok, used: 481/7854 (6%)
disk: ok, used: /:270305/338869 (79%), /software:57272/87462892 (0%)
process: warning, running: 4/5, failed: sshd
networking: ok
logs: ok, errors: caf (0)
apps: ok,
Administrators can see the status of IOx functionality by using the show iox detail command, as shown in the following example:
switch#show iox detail
IOx InfrastructureSummary:
---------------------------
Services State : OK
NetworkingConfigured: : OK
IOSNetworkReachable : OK
HostInfrastructureState: OK
.
.
.
IOx Processes State:
--------------------
caf : Running
ioxhad : Running
libvirtd : Running
monit : Running
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect Cisco IOS XE Software, Cisco IOS XR Software, or Cisco NX-OS Software.
There are no workarounds that address this vulnerability.
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.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 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 fixed this vulnerability in the following releases:
Cisco expects to fix this vulnerability in the following releases:
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
This vulnerability was found during internal security testing.
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 |
|---|---|---|---|---|
| 1.0 | Initial public release. | - | Final | 2019-September-25 |
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