Cisco Security Advisory
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CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
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A vulnerability in the filesystem of Cisco IOS XE Software could allow an authenticated, local attacker within the IOx Guest Shell to modify the namespace container protections on an affected device.
The vulnerability is due to insufficient file permissions. An attacker could exploit this vulnerability by modifying files that they should not have access to. A successful exploit could allow the attacker to remove container protections and perform file actions outside the namespace of the container.
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://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190925-iox-gs
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Vulnerable Products
At the time of publication, this vulnerability affected Cisco devices that were running a vulnerable release of Cisco IOS XE Software and had IOx Guest Shell enabled.
For information about which Cisco IOS XE Software releases were vulnerable at the time of publication, see the Fixed Software section of this advisory.
Administrators can determine if IOx Guest Shell is enabled by executing the show app-hosting list privileged command. The following command output shows a device with IOx Guest Shell enabled:
Device# show app-hosting list App id State ------------------------------------------------------ guestshell RUNNINGProducts Confirmed Not Vulnerable
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 Software, Cisco IOS XR Software, or Cisco NX-OS Software.
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The IOx Guest Shell is a virtualized, Linux-based environment designed to run custom Linux applications, including Python for automated control and management of Cisco devices. It can also automatically provision systems. This container shell provides a secure environment, decoupled from the host device, in which users can run scripts or install and run software packages.
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There are no workarounds that address this vulnerability.
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For detailed information about affected and fixed software releases, consult the Cisco IOS Software Checker.
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.
Cisco IOS and IOS XE Software
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:
- Initiate a search by choosing one or more releases from a drop-down list or uploading a file from a local system for the tool to parse
- Enter the output of the show version command for the tool to parse
- Create a custom search by including all previously published Cisco Security Advisories, a specific advisory, or all advisories in the most recent bundled publication
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 or IOS XE Software release—for example, 15.1(4)M2 or 3.13.8S—in the following field:
By default, the Cisco IOS Software Checker includes results only for vulnerabilities that have a Critical or High Security Impact Rating (SIR). To include results for Medium SIR vulnerabilities, use the Cisco IOS Software Checker on Cisco.com and check the Medium check box in the Impact Rating drop-down list.
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.
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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.
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This vulnerability was found during internal security testing.
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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.
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Show LessVersion Description Section Status Date 1.0 Initial public release. — Final 2019-September-25
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