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AUSCERT External Security Bulletin Redistribution
ESB-2015.2127
Cisco Nexus Operating System Address Resolution Protocol
Denial of Service Vulnerability
17 August 2015
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AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco NX-OS Software
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Denial of Service -- Remote/Unauthenticated
Resolution: Mitigation
CVE Names: CVE-2015-4323
Original Bulletin:
http://tools.cisco.com/security/center/viewAlert.x?alertId=40469
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Vulnerability Alert
Cisco Nexus Operating System Address Resolution Protocol Denial of Service
Vulnerability
Threat Type: CWE-119: Buffer Errors
IntelliShield ID: 40469
Version: 1
First Published: 2015 August 14 19:25 GMT
Last Published: 2015 August 14 19:25 GMT
Port: Not available
CVE: CVE-2015-4323
Urgency: Unlikely Use
Credibility: Confirmed
Severity: Mild Damage
CVSS Base: 6.1
CVSS Version 2.0
CVSS Temporal: 5.8
Version Summary: Cisco Nexus Operating System Address Resolution Protocol
contains a vulnerability that could allow an unauthenticated, adjacent
attacker to cause a denial of service condition. Updates are unavailable.
Description
A vulnerability in the Address Resolution Protocol (ARP) input packet
processing of the Cisco Nexus Operating System (NX-OS) devices could allow an
unauthenticated, adjacent attacker to cause a denial of service (DoS)
condition.
The vulnerability is due to improper validation of the ARP packet and the
maximum transmission unit (MTU) size, which results in a buffer overflow and
could cause a DoS condition. An attacker could exploit the vulnerability by
sending a crafted ARP packet to the device. An exploit could allow the
attacker to cause the device to become unavailable due to the DoS condition of
the ARP module.
Cisco has confirmed the vulnerability. Software updates are unavailable.
Warning Indicators
Cisco NX-OS Software is vulnerable.
IntelliShield Analysis
An unauthenticated, adjacent attacker could exploit this vulnerability if the
targeted device is set to default configuration settings and running the
affected version of the software.
To exploit this vulnerability, an attacker must be on the same broadcast or
collision domain as the affected device. This access requirement could
decrease the likelihood of a successful exploit.
Vendor Announcements
Cisco has released bug IDs CSCuv71933, CSCuv61341, CSCuv61321, CSCuu78074,
CSCut37060, CSCuv61266, CSCuv61351, CSCuv61358, and CSCuv61366 for registered
users, which contain additional details and up-to-date lists of affected
product versions.
Impact
An unauthenticated, adjacent attacker could exploit this vulnerability to
create a DoS condition on the targeted device.
Technical Information
The vulnerability is due to improper input validation of the ARP packet and
the MTU size on the targeted device.
An unauthenticated, adjacent attacker could exploit this vulnerability by
sending a crafted ARP packet to the targeted device. An exploit could allow
the attacker to cause the device to be unavailable due to a DoS condition in
the ARP module.
Safeguards
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to access local
systems.
Administrators are advised to monitor affected systems.
Administrators may consider using IP-based access control lists (ACLs) to
allow only trusted systems to access the affected systems.
Administrators are advised to lower the configuration of the MTU size.
Patches/Software
Updates are unavailable.
Alert History
Initial Release
Product Sets
The security vulnerability applies to the following combinations of products.
Primary Products:
Cisco Cisco NX-OS Software Cisco Nexus 1000V Switch for VMware vSphere
7.3(0)ZN(0.9) | for Nexus 3000 Series 7.3(0)ZN(0.83), 7.0(3)I2(0.373),
6.0(2)U5(1.41) | for Nexus 4000 Series 4.1(2)E1(1b) | for Nexus 7000 Series
6.2(14)S1 | for Nexus 9000 Series 7.3(0)ZN(0.9)
Cisco Cisco MDS 9000 NX-OS 6.2 (13) | 7.1(0)ZN(91.99) Base
Software
Cisco Cisco MDS SAN-OS 7.1(0)ZN(91.99) Base
Software
Associated Products:
N/A
LEGAL DISCLAIMER
The urgency and severity ratings of this alert are not tailored to individual
users; users may value alerts differently based upon their network
configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED
THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF
GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED
THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION
IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE
TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES
THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.
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