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AUSCERT External Security Bulletin Redistribution
Cisco Nexus Operating System Devices Command Line Interface
Local Privilege Escalation Vulnerability
2 July 2015
AusCERT Security Bulletin Summary
Product: Cisco NX-OS Software
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Increased Privileges -- Existing Account
CVE Names: CVE-2015-4237
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Cisco Nexus Operating System Devices Command Line Interface Local Privilege
Threat Type: CWE-264: Permissions, Privileges, and Access Control
IntelliShield ID: 39583
First Published: 2015 July 01 20:38 GMT
Last Published: 2015 July 01 20:38 GMT
Port: Not available
Urgency: Unlikely Use
Severity: Mild Damage
CVSS Base: 4.3
CVSS Version 2.0
CVSS Temporal: 4.1
Version Summary: Cisco Nexus devices contain a vulnerability that could allow
an authenticated, local attacker to gain elevated privileges on a targeted
system. Updates are not available.
A vulnerability in the Command Line Interface (CLI) parser of Cisco Nexus
Operating System (NX-OS) devices could allow an authenticated, local attacker
to perform a privilege escalation.
The vulnerability is due to improper input validation of special characters
within filenames. An attacker could exploit this vulnerability by
authenticating at the local shell and writing a file to disk with certain
special characters. The attacker could then use that file with other CLI
commands to obtain a shell prompt at their current privilege level. An exploit
could allow the attacker to read and write files and perform other privileged
Cisco has confirmed the vulnerability; however, software updates are not
At the time this alert was first published, Cisco Nexus devices running the
following Cisco NX-OS Software releases were vulnerable:
Cisco NX-OS Software release 9.1(1)SV1(3.1.8)
Cisco NX-OS Software release 7.2(0)ZZ(99.1)
Cisco NX-OS Software release 7.2(0)ZZ(99.3)
Cisco NX-OS Software release 4.1(2)E1(1)
Cisco NX-OS Software release 6.2(12)
Cisco NX-OS Software release 6.2(11b)
Later releases of Cisco NX-OS Software may also be vulnerable.
To exploit this vulnerability, an attacker must have local access and be able
to authenticate to the targeted device. These requirements could limit the
possibility of a successful exploit.
Cisco would like to thank Jens Krabbenhoeft for discovering and reporting this
Cisco has released bug IDs CSCuv08491, CSCuv08443, CSCuv08480, CSCuv08448,
CSCuu99291, CSCuv08434, and CSCuv08436 for registered users, which contains
additional details and an up-to-date list of affected product versions.
An authenticated, local attacker could exploit this vulnerability to gain
elevated privileges on an affected device. A successful exploit could be used
to conduct further attacks.
The vulnerability is due to insufficient validation of user input within
filenames by an affected device.
An attacker could exploit this vulnerability by authenticating at the local
shell on a targeted device and writing a file to disk with certain special
characters. An exploit could allow the attacker to perform other privileged
commands, which could be leveraged to conduct further attacks.
Administrators are advised to contact the vendor regarding future updates and
Administrators are advised to allow only trusted users to access local
Administrators are advised to allow only privileged users to access
administration or management systems.
Administrators are advised to monitor affected systems.
Software updates are not available.
The security vulnerability applies to the following combinations of products.
Cisco Cisco NX-OS Software for Nexus 3000 Series 7.2(0)ZZ(99.1) | for Nexus
4000 Series 4.1(2)E1(1) | for Nexus 5000 Series 7.2(0)ZZ(99.1) | for Nexus
7000 Series 6.2(12) | for Nexus 9000 Series 7.2(0)ZZ(99.3)
Cisco Cisco MDS 9000 NX-OS Software 6.2 (11b)
Cisco Cisco Nexus 1000V Switch 9.1(1)SV1(3.1.8) Base
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The urgency and severity ratings of this alert are not tailored to individual
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THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF
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TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES
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