12 June 2015
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2015.1528 Cisco Nexus and Cisco Multilayer Director Switches MOTD Telnet Login Reset Vulnerability 12 June 2015 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco Nexus Cisco Multilayer Director Switches Publisher: Cisco Systems Operating System: Cisco Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Mitigation CVE Names: CVE-2015-0775 Original Bulletin: http://tools.cisco.com/security/center/viewAlert.x?alertId=39280 - --------------------------BEGIN INCLUDED TEXT-------------------- Vulnerability Alert Cisco Nexus and Cisco Multilayer Director Switches MOTD Telnet Login Reset Vulnerability Threat Type: CWE-399: Resource Management Errors IntelliShield ID: 39280 Version: 1 First Published: 2015 June 10 19:29 GMT Last Published: 2015 June 10 19:29 GMT Port: Not available CVE: CVE-2015-0775 Urgency: Possible use Credibility: Confirmed Severity: Mild Damage CVSS Base: 5.0 CVSS Version 2.0 CVSS Temporal: 4.8 Version Summary: Cisco Nexus and Cisco Multilayer Director Switches contain a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Software updates are not available. Description A vulnerability in the Message of the Day (MOTD) or banner functionality of the NX-OS Software could allow an unauthenticated, remote attacker to cause the login process to reset. The vulnerability is due to the MOTD display handling when a certain type of terminal session is requested via Telnet. An attacker could exploit this vulnerability by repeatedly issuing a Telnet session to the NX-OS device, causing the login process to reset. An exploit could allow the attacker to cause the login process of the NX-OS device to reset repeatedly. Cisco has confirmed the vulnerability; however, software updates are not available. Warning Indicators The following Cisco Nexus and Cisco Multilayer Director Switches running the following releases of Cisco NX-OS Software are affected. Cisco Nexus 5000 Series Switches running NX-OS Software release 6.0(2)N2(2) Cisco Nexus 7000 Series Switches running NX-OS Software release 6.2(12) Cisco MDS 9000 Series Multilayer Switches running NX-OS Software release 6.2(11) Cisco Nexus 9000 Series Switches running NX-OS Software release 7.0(3) Cisco Nexus 3000 Series Switches running NX-OS Software release 7.2(0)ZN(99.67) Cisco Nexus 4000 Series Switches running NX-OS Software release 4.1(2)E1(1f) Cisco Nexus 1000V Switches running NX-OS Software release 5.2(1)SV3(2.1) IntelliShield Analysis To exploit this vulnerability, an attacker would need to start a Telnet session with the targeted device. This requirement may decrease the likelihood of a successful exploit depending on how the targeted device is configured. Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available. Vendor Announcements Cisco has released bug IDs CSCuo10554, CSCuu75466, CSCuu75471, CSCuu75484, CSCuu75498, CSCuu77182, and CSCuu77170 for registered users, which contain additional details and an up-to-date list of affected product versions. Impact An unauthenticated, remote attacker could exploit this vulnerability to cause the login process on an affected device to reset repeatedly, resulting in a denial of service (DoS) condition. Technical Information The vulnerability is due to improper handling of the MOTD display when a certain type of terminal session is requested via Telnet. An unauthenticated, attacker could exploit this vulnerability by repeatedly issuing a Telnet session to a targeted device. An exploit could allow the attacker to cause the login process of the device to reset repeatedly, resulting in a DoS condition. Safeguards Administrators are advised to contact the vendor regarding future updates and releases. Administrators are advised to allow only trusted users to have network access. Administrators can help protect affected systems from external attacks by using a solid firewall strategy. Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems. Administrators are advised to monitor affected systems. Patches/Software Software updates are not available. Alert History Initial Release Product Sets The security vulnerability applies to the following combinations of products. Primary Products: Cisco Cisco NX-OS Software for Nexus 3000 Series 7.2(0)ZN(99.67) | for Nexus 4000 Series 4.1(2)E1(1f) | for Nexus 5000 Series 6.0(2)N2(2) | for Nexus 7000 Series 6.2(12) | for Nexus 9000 Series 7.0(3) Cisco Cisco MDS 9000 NX-OS Software 6.2 (11) Cisco Cisco Nexus 1000V Switch 5.2(1)SV3(2.1) Base Associated Products: N/A Alerts and bulletins on the Cisco Security Intelligence Operations Portal are highlighted by analysts in the Cisco Threat Operations Center and represent a subset of the comprehensive content that is available through Cisco Security IntelliShield Alert Manager Service. This customizable threat and vulnerability alert service provides security staff with access to timely, accurate, and credible information about threats and vulnerabilities that may affect their environment. 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. - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. 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