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AUSCERT External Security Bulletin Redistribution
30 November 2017
AusCERT Security Bulletin Summary
Product: Cisco MDS Multilayer Director Switches
Cisco Nexus 7000 Series Switches
Cisco Nexus 7700 Series Switches
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Execute Arbitrary Code/Commands -- Existing Account
CVE Names: CVE-2017-12340
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2017 November 29 16:00 GMT
No workarounds available
Cisco Bug IDs:
A vulnerability in Cisco NX-OS System Software running on Cisco MDS
Multilayer Director Switches, Cisco Nexus 7000 Series Switches, and
Cisco Nexus 7700 Series Switches could allow an authenticated, local
attacker to access the Bash shell of an affected device's operating
system, even if the Bash shell is disabled on the system.
The vulnerability is due to insufficient sanitization of user-supplied
parameters that are passed to certain functions of the Python
scripting sandbox of the affected system. An attacker could exploit
this vulnerability to escape the scripting sandbox and enter the Bash
shell of the operating system with the privileges of the authenticated
user for the affected system. To exploit this vulnerability, the
attacker must have local access to the affected system and be
authenticated to the affected system with administrative or Python
There are no workarounds that address this vulnerability.
This advisory is available at the following link:
This vulnerability affects the following Cisco products if they are
running a vulnerable release of Cisco NX-OS System Software:
MDS Multilayer Director Switches
Nexus 7000 Series Switches
Nexus 7700 Series Switches
For information about affected software releases, consult the Cisco
bug ID(s) at the top of this advisory.
Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by this
Cisco has confirmed that this vulnerability does not affect the
following Cisco products:
Firepower 2100 Series Next-Generation Firewalls
Firepower 4100 Series Next-Generation Firewalls
Firepower 9300 Security Appliances
Nexus 1000V Series Switches
Nexus 2000 Series Fabric Extenders
Nexus 3000 Series Switches
Nexus 3500 Platform Switches
Nexus 5000 Series Switches
Nexus 5500 Platform Switches
Nexus 5600 Platform Switches
Nexus 6000 Series Switches
Nexus 9000 Series Fabric Switches in Application Centric
Infrastructure (ACI) mode
Nexus 9000 Series Switches in standalone NX-OS mode
Nexus 9500 R-Series Line Cards and Fabric Modules
Unified Computing System Manager
There are no workarounds that address this vulnerability.
For information about fixed software releases, consult the Cisco bug
ID(s) at the top of this advisory.
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.
Exploitation and Public Announcements
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.
Cisco Security Vulnerability Policy
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.
Related to This Advisory
Cisco Nexus 7000 Series NX-OS Programmability Guide
Version Description Section Status Date
1.0 Initial public release. Final 2017-November-29
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.
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